Immune support and respiratory infection care
Use of drugs and supplements for «immune boosting», prevention, and non-specific treatment of acute respiratory infections, influenza, and COVID-19. Covers immunomodulators and homeopathic agents for respiratory infections, hydroxychloroquine and colchicine for COVID, nebulized inhaled corticosteroids for adult acute respiratory infections, and supplements for post-COVID syndrome. Evidence base is limited or absent.
65 drugs
Also known as: immune boosting, respiratory infection prevention, immunostimulants, Immune support, Immune strengthening
Marketing claims without evidence base
The drug is promoted for these uses outside international guidelines. Each entry below is analyzed against AEMPS, FDA, EMA, Cochrane and major RCTs.
- DAlloferon (Allokin-alfa)Not recommended · Immunomodulators, antivirals (local classification). Russian development.Allokin-alpha is used off-label in Russia as an immunomodulator for frequently ill people. International clinical guidelines (WHO, NICE, CDC, IDSA) do not include the drug; the FDA, EMA, and AEMPS have not approved it. No independent international clinical studies exist. If allokin-alpha was recommended, consider seeking a second opinion.
- DAminodihydrophthalazinedione sodiumNot recommended · Immunomodulators (local classification). Russian development.Galavit is marketed in Russia as a universal immunomodulator across a broad range of infections, inflammation, and postoperative rehabilitation. International clinical guidelines (WHO, NICE, IDSA) do not include the drug; the FDA, EMA, and AEMPS have not approved it. No independent international clinical studies exist. Galavit does not replace evidence-based treatment of bacterial complications of a cold. If it has already been prescribed, discuss options with proven efficacy with your doctor.
- DAnaferon (anti-human interferon gamma antibodies in homeopathic dilutions)Not recommended · Homeopathic medicinesAnaferon is a tablet containing antibodies to human gamma-interferon at homeopathic dilutions, marketed to support immunity and help with colds and flu. Studies have not shown convincing benefit for this use: international guidelines and good-quality RCTs do not list it as an agent with proven effect. Colds ease with rest, fluids and symptom relief; for influenza in at-risk patients a doctor may prescribe oseltamivir. Do not take it in place of treatment with proven benefit.
- DAndrographis paniculataNot recommended · Plant immunomodulator, supplement. In EU – traditional herbal medicinal product (EMA HMPC monograph 2013)Andrographis is sold as «immunity boosting and URI prophylaxis». The Hu 2017 systematic review in a prophylaxis subgroup showed moderate cold frequency reduction with long-term (3-month) intake in adults, but the number and quality of these trials are limited. EMA HMPC 2013 recognises «short-term traditional use for common cold», not long-term prophylaxis. EFSA approved no «immunity» health claim for andrographis. For URI prevention international guidelines list hand hygiene, influenza and pneumococcal vaccination in risk groups; herbal supplements are not in recommendations. Long-term andrographis intake (>8 weeks) is associated with hepatotoxicity and allergic reaction risk.
- DAstragalus root (Astragalus membranaceus; Huang Qi in traditional Chinese medicine)Not recommended · Root of the perennial legume Astragalus membranaceus and its extracts. In traditional Chinese medicine, Huang Qi is used to «tonify Qi»; modern marketing sells it as an «immune modulator», a «longevity and telomere supplement», and supportive care in oncology. Neither AEMPS nor EMA registers it as a medicine; the EMA HMPC has not published a dedicated monograph on astragalus. AESAN classifies it as a complemento alimenticio. FDA has issued no approval.Astragalus is marketed as a «natural immune modulator» and a cold prevention agent. In animal models astragalus polysaccharides increase T- and B-cell proliferation. In humans, no high-quality RCTs with hard endpoints (lab-confirmed cold rates, symptom duration, hospitalisations) have been done. Cochrane has not published a systematic review on astragalus in cold or flu. NCCIH states that available data are too weak to recommend astragalus for immunity or infection prevention. Evidence-based seasonal measures are influenza and COVID-19 vaccination, hand hygiene, masking at peaks, control of chronic disease (diabetes, COPD), sleep, and adequate dietary protein. In patients on active immunosuppression (transplant, biological therapy for autoimmune disease), astragalus theoretically interferes with the immunosuppressive regimen and is not recommended.
- DAzoximer bromideNot recommended · Other immunostimulants (local classification)Polyoxidonium (azoximer bromide), marketed by Petrovax, is positioned as a universal immunomodulator across a broad range of infections, allergies, and postoperative settings. The FDA, EMA, and AEMPS have not approved the drug; international clinical guidelines (WHO, NICE, IDSA) do not include it. No independent high-quality studies confirm benefit: the available international publications are mostly sponsor-funded, open-label, or retrospective, without reliable clinical endpoints. If Polyoxidonium was recommended, consider seeking a second opinion.
- DBeta-1,3/1,6-D-glucan (yeast or oat)Not recommended · Polysaccharide immunomodulator. Oat beta-glucan is a dietary fibre with EFSA-approved cholesterol health claim. Yeast beta-glucan (Wellmune) is a supplement with immunity marketing without EFSA approvalYeast beta-glucan (Wellmune, Saccharomyces cerevisiae) is widely sold as a «natural immunomodulator» promising URI frequency reduction and cold symptom relief. Small RCTs Talbott 2009 in 75 post-marathon athletes and Auinger 2013 in 100 healthy volunteers showed moderate URI frequency and severity reduction with Wellmune 250 mg/day × 12 weeks. Evidence quality is limited by small samples, single-centre design and potential conflict of interest (sponsored by manufacturer). EFSA 2013 reviewed the «yeast beta-glucan helps to maintain body's defence against pathogens» claim and rejected it due to insufficient data. EFSA 2014 rejected again. AAFP 2019 and SEIMC 2020 for the common cold list symptomatic therapy first-line; beta-glucan is not in international guidelines. Oat beta-glucan as dietary fibre is not related to immune claims.
- DBifidobacterium longumNot recommended · Probiotic, Bifidobacterium genus bacteria. Supplement in Russia and Spain; marketing segment of «psychobiotics» promising gut-brain axis effects. AEMPS does not register it as a medicineBifidobacterium longum is a probiotic bacterium added to supplements and marketed to strengthen immunity and prevent colds and flu. Convincing benefit for this use has not been shown: there is no evidence base confirming that taking this strain leads to fewer respiratory infections or makes them milder. For a cold, rest, plenty of fluids and treating symptoms help, and for the flu a doctor may prescribe antivirals when indicated. The bacterium is harmless in this role, but do not rely on it instead of treatment with proven benefit, since that can mean missing the care you actually need.
- DBlack seed (Nigella sativa)Not recommended · Botanical supplement, black seed oil (Nigella sativa, thymoquinone); no EMA HMPC monographBlack seed is marketed as an «immune booster», especially in halal and ayurvedic shops, and intensively after the COVID-19 pandemic as «natural protection against viruses». The evidence base is weak. Reviews by Tavakkoli 2017 and later summaries describe thymoquinone effects in vitro and in animal models of influenza, asthma, and COVID-19, but few high-quality human RCTs with hard endpoints (lab-confirmed infection rates, hospitalisation, symptom duration) exist, and those are methodologically weak: small samples, varied source material, open-label designs. Cochrane has not published a systematic review on Nigella sativa for cold or flu prevention or treatment. The WHO Living Guidelines for COVID-19 (2023) and the Spanish SEIMC do not recommend black seed. Evidence-based seasonal measures are influenza and COVID-19 vaccination, hand hygiene, masking at peaks, sleep, and adequate dietary protein. If the product was bought «for immunity», consider seeking a second opinion – frequent infections, night sweats, or weight loss warrant assessment for haematological disease, HIV, or immunodeficiency rather than seed oil.
- DChlorophyll (chlorophyllin copper-sodium complex)Not recommended · Plant pigment; in supplements as natural chlorophyll (E140) and the water-soluble copper-sodium complex chlorophyllin (E141). In the European Union it is registered as a food colourant under Regulation (EC) 1333/2008. On iHerb, Amazon and in Spanish herbolarios «liquid chlorophyll» is sold as detox, a source of «liquid sunshine», anti-age, and an acne remedy. AEMPS does not register it as a medicine; AESAN classifies it as a complemento alimenticio without therapeutic indication. FDA has a single OTC-approved use – internal deodorant for ostomy, ileostomy, and incontinence (21 CFR 357.850, Derifil 100 mg)Sodium copper chlorophyllin (often sold as "liquid chlorophyll") is marketed as a supplement that supports immunity and helps you recover faster from colds and other respiratory infections. There is no convincing evidence that it shortens a cold, eases symptoms, or lowers how often people get sick: the evidence base for this use has not been established. For a respiratory infection, supportive care helps (fluids, rest, fever reducers when needed), and for influenza with risk factors a doctor may prescribe antivirals with proven benefit. Chlorophyll is harmless in this role, but do not take it instead of treatment with proven benefit, or you risk missing the right care.
- DCod liver oilNot recommended · Cod liver oil: EPA and DHA combined with retinol (vitamin A) and cholecalciferol (vitamin D3); registered as a medicine in SpainCod liver oil supplies omega-3 fatty acids and vitamins A and D, and it's promoted to strengthen immunity and ward off colds and respiratory infections. So far studies haven't shown a convincing benefit for this use: the supplement doesn't cut how often you catch seasonal infections or how long they last. The oil itself is safe in this role. To prevent respiratory infections, other measures work – flu vaccination, hand hygiene and enough sleep, and a vitamin D deficit is worth correcting only after a blood test.
- DCordyceps (Cordyceps sinensis, Cordyceps militaris)Not recommended · Medicinal mushroom of Tibetan and Chinese medicine, supplement. AEMPS does not register as medicineCordyceps refers to the fungi Cordyceps sinensis and Cordyceps militaris, sold as a supplement for immune support and help with colds and respiratory infections. The benefit for this use has not been shown: there is no solid evidence that it prevents infections or eases their course. The substance itself is harmless in this role. For a cold the basics help most – rest, fluids, fever reducers as needed – and flu vaccination is what actually lowers infection risk.
- DElderberry (Sambucus nigra)Not recommended · Plant immunomodulator, supplement. In EU – traditional herbal medicinal product (EMA HMPC monograph on flowers, berries classified as food)Black elderberry is sold as an «immunity booster» promising URI prophylaxis. The Tiralongo 2016 RCT in 312 air-travellers showed moderate reduction in cold duration and severity with elderberry taken 10 days before and during the flight, but no reduction in incidence. EMA HMPC 2013 recognises elder flowers as a traditional herbal medicinal product, not a prophylactic. EFSA approved no «immunity» health claim for elderberry. For influenza prevention CDC and ECDC recommend annual vaccination in all aged ≥6 months; elderberry is not in international prophylaxis guidelines. If elderberry was recommended as a vaccination substitute or in an immunocompromised patient, consider seeking a second opinion.
- DEleutherococcus senticosus («Siberian ginseng»)Not recommended · Plant adaptogen, supplement. In EU – traditional herbal medicinal product (EMA HMPC); OTC tincture in RussiaEleuthero (Siberian ginseng) is a herbal product marketed as an adaptogen to boost immunity and prevent colds and flu. There is no convincing evidence that it lowers how often you get respiratory infections or helps you recover faster. What actually works against these infections: vaccination (flu, COVID-19), hand hygiene, and good sleep; for the symptoms themselves, rest and plenty of fluids.
- DErgoferon (antibodies to γ-interferon, CD4, and histamine in homeopathic dilutions)Not recommended · Homeopathic preparation marketed as an immunomodulator (local classification)Ergoferon contains antibodies to gamma-interferon, CD4 and histamine in homeopathic dilutions, and it is marketed to support immunity and ease the common cold. Convincing benefit for this use has not been shown: there is no evidence base confirming any effect on the course of a cold or flu. For acute respiratory infections, rest, fluids and fever reducers when needed help, and in flu at-risk groups a clinician may prescribe antivirals with proven efficacy. Do not use Ergoferon in place of treatment with proven benefit, since that risks missing the care you actually need.
- DHoly basil, tulsi (Ocimum sanctum, Ocimum tenuiflorum)Not recommended · Plant adaptogen from Ayurvedic medicine, supplement. Not registered as medicine in EU or AEMPSHoly basil (tulsi) is an Ayurvedic herb whose supplement extracts are promoted to strengthen immunity and prevent colds and flu. There is no convincing evidence that tulsi lowers how often people catch respiratory infections or how severe they get; the available studies are few and of low quality. A common cold gets better with rest, fluids and time, vaccination protects against flu, and a doctor may prescribe antivirals for people at higher risk. At usual doses tulsi is well tolerated, but its benefit for immunity has not been confirmed
- DKagocelNot recommended · Other antivirals (local classification)Kagocel is an antiviral marketed in Russia to prevent and treat colds and flu and to support immunity. Independent evidence has not shown convincing benefit for this use. For colds and flu, rest, fluids, and fever relief as needed help most, the annual flu shot gives real protection, and for severe flu a doctor may prescribe drugs with proven effect.
- DLactoferrinNot recommended · Bovine colostrum and human-milk glycoprotein supplement marketed as «immune modulator», «iron support» and «antiviral»Lactoferrin is a protein found in milk and other body fluids; in supplements it gets promoted for boosting immunity and preventing colds and respiratory infections. Reliable evidence for this use is missing – good studies have not shown that taking lactoferrin makes colds less frequent or milder. The substance itself is harmless in this role. To catch fewer respiratory infections, seasonal flu vaccination, hand washing, and enough sleep have far better support.
- DMonolaurin (glycerol monolaurate)Not recommended · Lauric acid derivative, supplement. No medicinal status in EU or Russia. AEMPS and AESAN do not register monolaurin as a medicineMonolaurin is a monoglyceride of lauric acid, sold as a supplement to support immunity and help with respiratory infections. There is no convincing evidence for this use: nothing reliably shows that monolaurin prevents colds or eases their course. For a respiratory infection, rest, fluids and time do the work, while flu vaccination and, when indicated, antivirals with proven benefit are what actually shorten or soften symptoms. Do not take monolaurin in place of treatment with proven benefit, since that can mean missing the care you need.
- DOlive leaf extract (Olea europaea, oleuropein)Not recommended · Plant antioxidant, supplement. In EU – traditional herbal medicinal product (EMA HMPC monograph 2014)Olive leaf extract (Olea europaea), whose active component is oleuropein, is marketed as a supplement for immune support and for preventing colds and other respiratory infections. There is no convincing evidence for this use: good-quality clinical trials showing an effect on how often people catch a respiratory infection or how it runs have not been done. For a cold, rest, fluids, and symptom relief are what actually help, and the main protection against flu is vaccination. The substance itself is harmless in normal dietary amounts, but do not use it instead of treatment with proven benefit, since that can mean missing the care you need.
- DPanax ginseng (Korean/Chinese ginseng)Not recommended · Plant adaptogen, supplement. In EU – traditional herbal medicinal product (EMA HMPC); OTC tincture in RussiaGinseng is sold for «immunity boosting» and «cold prevention». No Cochrane systematic review on ginseng for the common cold. Several small RCTs with CVT-E002 extract (Cold-fX, Panax quinquefolius) showed moderate cold frequency reduction in adults; data in the elderly are conflicting. EMA HMPC 2014 recognises «traditional use», not proven efficacy. AAFP and SEIMC for the common cold recommend symptomatic therapy (paracetamol for fever, fluids, rest); ginseng supplements are not in international guidelines.
- DProteolytic enzyme complex (bromelain, papain, pancreatin, trypsin, chymotrypsin, rutoside)Not recommended · Combined enzyme preparations, systemic enzyme therapy (local classification)A combination of proteolytic enzymes (bromelain, papain, pancreatin, trypsin, chymotrypsin) with rutoside. Manufacturers promote such products to boost immunity and ease the course of colds and flu-like infections. Studies have not shown convincing benefit for this use: there is no quality evidence that the combination prevents respiratory infections or speeds up recovery. For a common cold, rest, fluids, and symptom relief are usually enough, and a severe or prolonged course needs a doctor's assessment. The enzyme combination is harmless in this role, but it should not be taken instead of treatment with proven benefit, since that risks missing the care you actually need.
- DQuercetinNot recommended · Dietary supplements, flavonoids (local classification). Also registered in Russia as an angioprotective agent.Quercetin is a plant flavonoid found in onions, apples and capers, sold as a supplement for immunity and for preventing colds and respiratory infections. For this use there is no convincing benefit: the data come from small, low-quality trials. For an acute respiratory infection, rest, fluids and symptom relief help, and prevention rests on flu vaccination and hand hygiene. The compound itself is safe at typical dietary and supplement amounts.
- DReishi (Ganoderma lucidum, lingzhi)Not recommended · Medicinal mushroom of traditional Chinese medicine, supplement. AEMPS does not register as medicineReishi is Asia's top-selling medicinal mushroom with a 2000-year tradition as the «mushroom of immortality». In modern marketing – a «natural immunomodulator». Evidence base in healthy people for cold and respiratory viral infection prevention is weak: small RCTs recorded cytokine profile and NK cell activity changes without confirmed clinically meaningful frequency reduction. AAFP and SEIMC for the common cold recommend symptomatic therapy (paracetamol for fever, fluids, rest); reishi is not in international guidelines.
- DTurkey tail (Trametes versicolor, Coriolus versicolor)Not recommended · Medicinal mushroom. In Japan PSK (Krestin) approved as chemotherapy adjuvant for gastric cancer since 1977. In EU and AEMPS not registered as medicine; sold as supplementTrametes versicolor is sold for «immunity boosting» via T and NK cell stimulation. In healthy people for cold and respiratory viral infection prevention no quality RCTs with frequency or symptom duration endpoints. AAFP and SEIMC for the common cold recommend symptomatic therapy; turkey tail is not in international guidelines.
- Dα-Glutamyl-L-tryptophanNot recommended · Other immunostimulants (synthetic peptides, local classification)Thymogen is marketed as an immunoregulator for frequently ill adults and children as injection solution, spray, and ointment. International clinical guidelines (WHO, NICE, IDSA) do not include the drug; the FDA, EMA, and AEMPS have not approved it. No independent international clinical studies exist. If Thymogen was recommended, consider seeking a second opinion.
- FAciclovirNot recommended · Antiviral – nucleoside analogueAciclovir is an antiviral drug active against herpesviruses (HSV-1, HSV-2, VZV). It is prescribed for infections caused by these viruses – genital and orolabial herpes, chickenpox, and shingles (AEMPS Ficha Técnica). For common colds or flu, aciclovir does not work – respiratory virus pathogens (rhinoviruses, adenoviruses, coronaviruses, influenza) are not susceptible to this drug. Taking aciclovir at the first signs of a cold is not justified. The drug can cause nausea, headache, and acute kidney injury with intravenous administration. If aciclovir was prescribed for a cold, consider seeking a second opinion.
- FAmbroxolNot recommended · Mucolytic agentAmbroxol is a mucolytic that thins sputum. It is prescribed for chronic respiratory diseases with thick sputum – COPD, cystic fibrosis. For acute viral upper respiratory infections in children and adults, ambroxol is widely used for cold prevention and at the first signs of a cold. Ambroxol offers no benefit for immunity or cold prevention: it is a mucolytic, not an immunomodulator. The drug does carry documented risks. The 2015 EMA/PRAC referral on ambroxol and bromhexine confirmed a small risk of severe allergic and cutaneous reactions, including erythema multiforme and Stevens-Johnson syndrome, and of anaphylaxis; the benefit-risk balance for approved uses stayed positive and the product information was updated. If ambroxol was prescribed to a child for a cold without marked thick sputum, consider seeking a second opinion.
- FBacterial lysates OM-85Not recommended · Other immunostimulantsBronchomunal (OM-85, lyophilized bacterial lysate) is promoted by the manufacturer as an immunostimulant for recurrent respiratory tract infections in frequently ill children and adults. Meta-analyses (Schaad 2010 and newer work) show modest reductions in respiratory infection frequency in children with recurrent colds, with modest and heterogeneous effects. International clinical guidelines include the drug to a limited extent (AEMPS Ficha Técnica supports use in patients with recurrent respiratory tract infections); the FDA has not approved it. In healthy children and adults without recurrent infections, prophylactic use is not justified. If OM-85 was recommended without confirmed recurrent respiratory tract infections, consider seeking a second opinion.
- FBeclomethasone dipropionateNot recommended · Inhaled corticosteroids (ICS)Beclomethasone is an inhaled or nasal corticosteroid. It is prescribed for asthma (inhaled) and allergic rhinitis (nasal). In Russia and the CIS, beclomethasone is regularly nebulized to adults and children for acute respiratory infections outside an asthma indication. No clinical studies of nebulization use for colds exist. The drug causes oropharyngeal candidiasis, hoarseness, and with systemic absorption at high doses adrenal suppression. If beclomethasone was prescribed via nebulizer for a cold, consider seeking a second opinion.
- FBilastineNot recommended · Second-generation antihistamineBilastine is a second-generation antihistamine. It is prescribed for seasonal and perennial allergic rhinitis and urticaria (EAACI 2024, AEMPS Ficha Técnica). Bilastine is taken for colds and for immunity with the expectation that the antihistamine effect will relieve runny nose and congestion in respiratory infections. The Cochrane review by De Sutter 2015 (16 RCTs) in people with common colds did not confirm benefit of antihistamines as monotherapy. Second-generation antihistamines (bilastine, cetirizine, loratadine, and others) cause virtually no drowsiness – a marketing advantage – but also no cold-relieving effect. If bilastine was prescribed for a cold without confirmed allergic rhinitis, consider seeking a second opinion.
- FBromhexineNot recommended · Mucolytic agentBromhexine is a mucolytic. It is prescribed for chronic respiratory diseases with thick sputum. For acute viral infections, bromhexine is widely recommended for sputum thinning in colds and for immune support. The Cochrane review by Chalumeau 2013 does not recommend mucolytics in children under 4. The drug carries specific risks: allergic reactions, with cases of severe skin reactions described. For ordinary colds without marked thick sputum, mucolytics are not justified – treatment is based on rest, humidified air, plenty of fluids, and symptomatic agents (paracetamol for fever). If bromhexine was prescribed for an ordinary cold, consider seeking a second opinion.
- FBudesonide/formoterolNot recommended · Inhaled corticosteroid (ICS) plus long-acting β2-agonist (LABA) combination with rapid onsetBudesonide/formoterol is a fixed combination of an inhaled corticosteroid (ICS) and a long-acting β2-agonist. It is prescribed for asthma and COPD (GINA 2024, GOLD 2024, AEMPS Ficha Técnica). Budesonide/formoterol is used for cold prevention and enhanced breathing outside an asthma or COPD indication. No clinical studies of prophylactic use in this setting exist. The drug causes hoarseness, oropharyngeal candidiasis, and with long-term high-dose use systemic corticosteroid effects (adrenal insufficiency, osteoporosis, cataract). If budesonide/formoterol was prescribed outside confirmed asthma or COPD, consider seeking a second opinion.
- FCarbocisteineNot recommended · Mucolytic agentCarbocisteine is a mucolytic. It is prescribed for chronic respiratory diseases with thick sputum. For acute viral infections in children, carbocisteine is prescribed at the first signs of a cold and to enhance the immune response. The Cochrane review by Chalumeau 2013 and the EMA PRAC restricted carbocisteine use in children under 2 due to risk of paradoxical worsening of breathing. The drug carries specific risks: allergic reactions and GI disturbances. If carbocisteine was prescribed to a child for an ordinary cold, consider seeking a second opinion.
- FCetylpyridiniumNot recommended · Cationic quaternary ammonium antiseptic for topical use in the mouth and throatThe second marketing line for antiseptic lozenges is «immune support and cold prevention in autumn». Cetylpyridinium does nothing to immunity: it is a surfactant that destroys microbial membranes where it lands and is washed away by saliva in 20 to 30 minutes. There are no prevention studies in which regular lozenge use lowered the rate of respiratory infections, and the AEMPS ficha técnica limits use to seven days and only for throat irritation already present. Continuous use of a topical antiseptic is not harmless: the ficha names sensitization and mucosal burning. The number of respiratory infections falls with enough sleep, hand washing and influenza vaccination. If antiseptic lozenges were offered as a course «for prevention», consider seeking a second opinion.
- FChaga (Inonotus obliquus)Not recommended · Medicinal mushroom parasitising birch. In Russia OTC «Befungin» registered, in the West – supplement. AEMPS does not register as medicineChaga is sold for «immunity boosting» and «cold prevention». No Cochrane systematic review on chaga for colds or respiratory viral infections. No quality international RCTs with frequency and symptom duration endpoints. AAFP and SEIMC for the common cold recommend symptomatic therapy; chaga is not in international guidelines.
- FColchicineNot recommended · Antigout agentsColchicine is an anti-inflammatory drug that inhibits microtubule polymerization. It is prescribed for acute gout, familial Mediterranean fever, pericarditis, and Behçet's disease (EULAR 2023, AEMPS Ficha Técnica). Colchicine is positioned as a drug to suppress cytokine storm in colds and flu. The COLCORONA trial (Tardif 2021) in outpatient COVID-19 did not meet the primary endpoint; international clinical guidelines (WHO Living Guideline 2023, NIH COVID-19 Guidelines 2024) do not include colchicine for COVID-19 or common colds. The drug has a narrow therapeutic index: overdose causes severe diarrhea, vomiting, myelosuppression, neuropathy, myopathy, and multi-organ failure; fatalities have been described at doses from 7 mg. If colchicine was recommended for an ordinary cold or respiratory infection, consider seeking a second opinion.
- FDesloratadineNot recommended · Second-generation antihistamineDesloratadine is a second-generation antihistamine and the active metabolite of loratadine. It is prescribed for seasonal and perennial allergic rhinitis and urticaria (EAACI 2024, AEMPS Ficha Técnica). Desloratadine is recommended for viral runny nose and for general immunity, conflating the common cold with allergic rhinitis. The Cochrane review by De Sutter 2015 in people with ordinary colds did not confirm significant effect of antihistamines as monotherapy. If desloratadine was prescribed for a cold without confirmed allergic rhinitis, consider seeking a second opinion.
- FEbastineNot recommended · Second-generation antihistamineEbastine is a second-generation antihistamine. It is prescribed for seasonal and perennial allergic rhinitis and urticaria (EAACI 2024, AEMPS Ficha Técnica). Ebastine is used in seasonal colds and viral congestion as a universal anti-allergic agent. AAAAI 2024 and the Cochrane review by De Sutter 2015 did not confirm significant benefit of antihistamines in the common cold. If ebastine was prescribed for a cold without confirmed allergic rhinitis, consider seeking a second opinion.
- FEchinacea purpurea (juice/extract)Not recommended · Herbal immunomodulators (local classification)Echinacea is one of the most heavily marketed herbal supplements for immunity in retail pharmacies. Cochrane systematic reviews (Karsch-Volk 2014, 24 RCTs) in people with colds showed heterogeneous and overall modest effects: some echinacea preparations may slightly reduce cold risk or duration (by 10–20%), but evidence quality is low and different echinacea preparations differ in composition and standardization. International clinical guidelines do not include echinacea. The supplement is relatively safe but can cause allergic reactions in people allergic to Asteraceae plants. If echinacea was recommended, consider seeking a second opinion; any immunity effect is small.
- FFexofenadineNot recommended · Second-generation antihistamineFexofenadine is a second-generation antihistamine. It is prescribed for seasonal and perennial allergic rhinitis and urticaria (EAACI 2024). Fexofenadine is taken at the first signs of a cold and for immunity, expecting a systemic anti-allergic effect. The Cochrane review by De Sutter 2015 did not confirm significant benefit of antihistamines in the common cold. If fexofenadine was prescribed for a cold without confirmed allergic rhinitis, consider seeking a second opinion.
- FFluconazoleNot recommended · Antifungals, triazole derivativesFluconazole is a triazole antifungal. It is prescribed for mucosal and cutaneous candidiasis, invasive candidiasis, and prophylaxis in immunocompromised patients (IDSA 2024). Fluconazole is prescribed for prophylaxis in patients on antibiotics and for intestinal dysbiosis in immunocompetent adults and children. The concept of post-antibiotic intestinal dysbiosis lacks a clear definition in international medicine; routine antifungal prophylaxis with antibiotics in immunocompetent people is not indicated (IDSA 2024). The drug can cause hepatotoxicity, QT prolongation, and drug interactions via CYP3A4. If fluconazole was prescribed after antibiotics or for dysbiosis, consider seeking a second opinion.
- FFluticasone furoate (nasal)Not recommended · Intranasal corticosteroidNasal fluticasone furoate is used in children and adults for cold prevention and as nasal mucosal protection outside an allergic rhinitis or nasal polyps indication (approved indications: AEMPS Ficha Técnica, EAACI 2024). No clinical studies of prophylactic use for colds exist. The drug can cause nosebleeds, nasal septum perforation on long-term use, hoarseness, and with systemic absorption at high doses HPA axis suppression. If nasal fluticasone furoate was prescribed for cold prevention, consider seeking a second opinion.
- FFluticasone propionateNot recommended · Inhaled corticosteroids (ICS)Fluticasone propionate is an inhaled or nasal corticosteroid. It is prescribed for asthma (inhaled) and allergic rhinitis or nasal polyps (nasal) (GINA 2024, EAACI 2024). In Russia and the CIS, fluticasone propionate is nebulized to children and adults for acute respiratory infections, bronchitis, and laryngitis outside an asthma indication. No clinical studies of nebulization use for colds exist; this practice is dangerous – the drug causes oropharyngeal candidiasis, hoarseness, and with systemic absorption in children HPA axis suppression. If fluticasone propionate was prescribed via nebulizer for a cold, consider seeking a second opinion.
- FFluvoxamineNot recommended · SSRIFluvoxamine is an SSRI antidepressant. It is prescribed for obsessive-compulsive disorder and major depression (AEMPS Ficha Técnica). In 2021–2022, fluvoxamine was actively promoted for treatment and prevention of mild COVID-19 as a sigma-1 agonist with anti-inflammatory action in biohacker and alt circles, citing the TOGETHER trial (Reis 2021) with Brazilian participants and placebo control. WHO Living Guideline 2023 and NIH COVID-19 Guidelines 2024 do not recommend fluvoxamine for COVID-19 – the evidence base is limited to one trial with methodological constraints. The drug has standard antidepressant risks: nausea, sexual dysfunction, discontinuation syndrome, and serotonin syndrome when combined with other serotonergic drugs. If fluvoxamine was prescribed for colds or COVID-19 without confirmed depression or OCD, consider seeking a second opinion.
- FGlucosaminyl muramyl dipeptideNot recommended · Other immunostimulants (local classification)Likopid is marketed as an immunomodulator for correction of secondary immunodeficiencies in frequently ill children and adults. The FDA, EMA, and AEMPS have not approved the drug; international clinical guidelines (WHO, NICE, IDSA, CDC) do not include it. Secondary immunodeficiency in frequently ill people is not recognized as an independent diagnosis in international medicine – this is often a normal cold frequency in children or social-contact factors. No independent international clinical studies exist. If Likopid was recommended, consider seeking a second opinion.
- FHydroxychloroquineNot recommended · Antimalarials, aminoquinolinesHydroxychloroquine is an antimalarial and disease-modifying antirheumatic drug. It is prescribed for systemic lupus erythematosus, rheumatoid arthritis, discoid lupus erythematosus, and for malaria prevention and treatment (EULAR 2023, ACR 2020). In 2020 hydroxychloroquine was actively promoted as a COVID-19 treatment and prophylaxis. The RECOVERY (NEJM 2020) and Solidarity (WHO 2020) trials in tens of thousands of patients showed no benefit and a signal of increased mortality in hospitalized COVID-19 patients. WHO Living Guideline 2023 and NIH COVID-19 Guidelines 2024 strongly advise against hydroxychloroquine for COVID-19. The drug has serious risks on long-term use: irreversible retinopathy with vision-loss risk, QT prolongation, and cardiomyopathy. If hydroxychloroquine was recommended for COVID-19 or for immunity, consider seeking a second opinion.
- FImudon (polyvalent bacterial lysate)Not recommended · Other oral cavity preparations (local classification)Imudon (polyvalent bacterial lysate as oral lozenges) is marketed as an immunomodulator for oropharyngeal infections and for frequently ill people. International clinical guidelines (WHO, NICE, IDSA, CDC) do not include the drug; the FDA has not approved it. No systematic reviews with endpoints on oropharyngeal infection frequency exist. If Imudon was recommended, consider seeking a second opinion.
- FInosine pranobexNot recommended · Other antivirals with claimed immunostimulant effectIsoprinosine and Groprinosin (inosine pranobex) are marketed in Eastern Europe and the CIS as an immunostimulant for frequently ill children and adults. The FDA has not approved the drug; international clinical guidelines (WHO, NICE, IDSA, CDC) do not include it; in most EU countries it is registered but used selectively for confirmed viral infections (e.g., subacute sclerosing panencephalitis). No independent international RCTs with endpoints on cold frequency in frequently ill people exist. The drug can raise uric acid with risk of gout flare. If isoprinosine was recommended to a child or adult for immunity, consider seeking a second opinion.
- FInterferon alpha-2b (nasal formulations)Not recommended · Other topical nasal preparations (local classification)Grippferon and similar nasal forms of interferon α-2b are marketed as immunity drops and cold prevention. Systemic interferons have proven efficacy in some diseases (chronic viral hepatitis), but nasal forms do not achieve bioavailability for systemic effect. International clinical guidelines (WHO, NICE, IDSA, CDC) do not include the drug; the FDA, EMA, and AEMPS have not approved it. If Grippferon was recommended to a child or adult, consider seeking a second opinion.
- FInterferon α-2b in suppositoriesNot recommended · Interferons (suppositories, local classification)Viferon (recombinant interferon α-2b in suppositories), marketed by Feron, is promoted as an immunity agent for colds, flu, and other infections. International clinical guidelines (WHO, NICE, IDSA) do not include the drug. Systemic interferons have proven efficacy in specific diseases (chronic hepatitis B/C, some tumors), but rectal forms do not achieve bioavailability for systemic effect – absorption studies show minimal entry into the bloodstream. No independent international RCTs with endpoints on colds exist. If Viferon was recommended to a child or adult, consider seeking a second opinion.
- FLevocetirizineNot recommended · Second-generation antihistamineLevocetirizine is a second-generation antihistamine and the active enantiomer of cetirizine. It is prescribed for seasonal and perennial allergic rhinitis and urticaria (EAACI 2024). Levocetirizine is prescribed for cold to relieve mucosal edema and for immunity. The Cochrane review by De Sutter 2015 did not confirm benefit of antihistamines in the common cold. If levocetirizine was prescribed for a cold without confirmed allergic rhinitis, consider seeking a second opinion.
- FMeglumine acridone acetateNot recommended · Other immunostimulants (local classification)Cycloferon (meglumine acridoneacetate), marketed by Polisan, is promoted as an immunity agent and interferon inducer for colds and other infections. International clinical guidelines (WHO, NICE, IDSA) do not include the drug; the FDA, EMA, and AEMPS have not approved it. No independent international clinical studies exist. If cycloferon was recommended, consider seeking a second opinion.
- FMometasone furoate (nasal)Not recommended · Intranasal corticosteroidNasal mometasone furoate is used for cold prevention and as nasal mucosal protection outside an allergic rhinitis or nasal polyps indication (EAACI 2024, AEMPS Ficha Técnica). No clinical studies of prophylactic use for colds exist. The drug can cause nosebleeds, nasal septum perforation on long-term use, hoarseness, and allergic reactions. If nasal mometasone furoate was prescribed for cold prevention, consider seeking a second opinion.
- FMontelukastNot recommended · Leukotriene receptor antagonistsMontelukast is a leukotriene receptor antagonist. It is prescribed for asthma (as a first-line alternative) and allergic rhinitis (GINA 2024 guidelines). For shortness of breath or allergy prevention outside asthma or allergic rhinitis, montelukast is not used. In 2020 the FDA added a boxed warning to the label about severe neuropsychiatric side effects: depression, anxiety, insomnia, nightmares, aggression, and suicidal thoughts and attempts. The FDA recommended avoiding montelukast for mild allergic rhinitis when other options are available (antihistamines, intranasal corticosteroids). If montelukast was prescribed for shortness of breath without confirmed asthma, consider seeking a second opinion, especially in children and adolescents.
- FPropolis (bee product)Not recommended · Bee product, supplement. Not registered as monomedicine in EU or AEMPS; OTC segment in Italy and GermanyPropolis is widely sold for «immune boosting» and «cold prevention». No evidence base with clinically meaningful endpoints (infection frequency, hospitalisation, illness duration); laboratory studies recorded cytokine profile and phagocyte activity changes without translation to human outcomes. EMA HMPC issued no propolis monograph. If propolis was recommended for frequent respiratory infections, consider seeking a second opinion: possible underlying causes (iron deficiency, vitamin D deficiency, chronic infection focus, immunodeficiency) require targeted workup.
- FRitonavirNot recommended · HIV protease inhibitor / pharmacokinetic boosterRitonavir is an HIV protease inhibitor used in combination with nirmatrelvir (Paxlovid) for treatment of mild-to-moderate COVID-19 in patients at high risk of progression (FDA EUA 2021, NIH COVID-19 Guidelines 2024). Stand-alone ritonavir is occasionally prescribed for immunity or COVID-19 without the full Paxlovid regimen. Without combination with nirmatrelvir or other antiretrovirals, ritonavir does not work in COVID-19; international clinical guidelines do not include such use. Ritonavir is a strong CYP3A4 inhibitor with severe drug interactions (statins, amiodarone, direct oral anticoagulants, some immunosuppressants are contraindicated). If ritonavir was prescribed without the full Paxlovid regimen or antiretroviral therapy, consider seeking a second opinion.
- FRupatadineNot recommended · Second-generation antihistamine with additional PAF antagonismRupatadine is a second-generation antihistamine with additional anti–platelet-activating factor activity. It is prescribed for seasonal and perennial allergic rhinitis and urticaria (EAACI 2024, AEMPS Ficha Técnica). Rupatadine is taken for cold-related runny nose and for immunity as a universal anti-allergic agent. The Cochrane review by De Sutter 2015 did not confirm benefit of antihistamines in the common cold. If rupatadine was prescribed for a cold without confirmed allergic rhinitis, consider seeking a second opinion.
- FSodium deoxyribonucleate (Derinat)Not recommended · Immunomodulators (local classification). Russian development.Derinat is marketed in Russia as an immunomodulator for frequently ill children and adults, available as drops, spray, and injection. International clinical guidelines (WHO, NICE, AAP, IDSA) do not include the drug; the FDA, EMA, and AEMPS have not approved it. No independent international clinical studies exist. If Derinat was recommended, consider seeking a second opinion.
- FTiloroneNot recommended · Other antivirals (local classification)Tilorone (Amixin, Lavomax) is a Soviet-era interferon inducer prescribed in Russia and the CIS for colds, flu, herpes, and immunity. International clinical guidelines (WHO, NICE, IDSA, CDC) do not include the drug; the FDA, EMA, and AEMPS have not approved it. No independent international clinical studies with endpoints on cold duration exist. The drug causes GI disturbances, allergic reactions, and hepatotoxicity has been described. If tilorone was recommended, consider seeking a second opinion.
- FTiotropiumNot recommended · Long-acting muscarinic antagonist for inhalation (LAMA)Tiotropium is a long-acting inhaled antimuscarinic (LAMA). It is prescribed for COPD and severe asthma as add-on therapy (GOLD 2024, GINA 2024). Tiotropium is used in inhaler form for enhanced breathing and exercise-related breathing difficulty outside a COPD or severe asthma indication. No clinical studies of prophylactic use in this setting exist. The drug causes dry mouth, urinary retention (especially in men with benign prostatic hyperplasia), and elevated intraocular pressure (especially in angle-closure glaucoma). If tiotropium was prescribed outside confirmed COPD or severe asthma, consider seeking a second opinion.
- FUmifenovirNot recommended · Other antiviralsArbidol (umifenovir) is promoted as an antiviral and immunomodulator for prevention and treatment of colds and flu. The drug is developed and produced mainly in Russia; international clinical guidelines (WHO, NICE, IDSA, CDC) do not include it; the FDA, EMA, and AEMPS have not approved it. The Cochrane Jefferson 2014 analysis in influenza did not confirm clinically meaningful benefit of umifenovir. If Arbidol was recommended, consider seeking a second opinion.
- FValacyclovirNot recommended · Antiviral – aciclovir prodrugValaciclovir is a prodrug of aciclovir with better bioavailability. It is prescribed for infections caused by herpesviruses (HSV-1, HSV-2, VZV) – genital and orolabial herpes, and shingles (AEMPS Ficha Técnica). For common colds or flu, valaciclovir does not work – respiratory virus pathogens are not susceptible to drugs in this class. Taking valaciclovir at the first signs of any cold is not justified. The drug can cause nausea, headache, and in susceptible patients acute kidney injury and thrombotic microangiopathy (rare). If valaciclovir was prescribed for a cold, consider seeking a second opinion.
- FVitaglutamNot recommended · Other antivirals (local classification)Ingavirin (vitaglutam) is positioned as an antiviral and immunomodulator for colds and flu. International clinical guidelines (WHO, NICE, IDSA, CDC) do not include the drug; the FDA, EMA, and AEMPS have not approved it. No independent international clinical studies with endpoints on flu or cold duration exist. For confirmed influenza, drugs with proven efficacy exist (oseltamivir, zanamivir per IDSA 2024 guidelines). If Ingavirin was recommended, consider seeking a second opinion.
- FVoriconazoleNot recommended · Triazole derivatives, systemic antifungalsVoriconazole is a broad-spectrum triazole antifungal. It is prescribed for invasive aspergillosis and other severe invasive mycoses in immunocompromised patients (IDSA 2024). Voriconazole is occasionally prescribed for prophylaxis in immunocompetent adults without confirmed invasive aspergillosis or severe mycoses. In immunocompetent people without a confirmed invasive mycosis diagnosis, no clinical studies of prophylactic use exist, and the risks are not justified. The drug has serious risks: hepatotoxicity, QT prolongation, photosensitivity with risk of cutaneous squamous cell carcinoma on long-term use, visual disturbances (visual hallucinations, color perception disturbances), and drug interactions. If voriconazole was prescribed without confirmed invasive mycosis, consider seeking a second opinion.
How to read tiers A–F
Evidence tiers belong to the drug-indication pair, not to the drug as a whole: the same substance can be A for one condition and F for another.
- AStrong evidence – first or second line in international guidelines
- BRecommended in selected cases
- CStudy data contradict each other
- DBenefit not proven, no documented harm
- FDocumented harm, or risk without benefit