Pseudoephedrine

Systemic decongestant, sympathomimetic

ATC code: R01BA02

Brand names: Sudafed

Updated 24 Sep 2026 · Methodology

Indications

Nasal congestion

Second line

Pseudoephedrine is a decongestant in tablet form: it opens the nose from inside, through the bloodstream, and is therefore used when drops do not suit or when both sides are blocked in a cold, influenza or rhinitis. The AEMPS ficha técnica sets a narrow frame: adults and adolescents from 12 years take one prolonged-release tablet every 12 hours, at most 240 mg a day, in a short course. The 2012 Cochrane review of antihistamine-decongestant-analgesic combinations for the common cold found small benefit in adults and adolescents and no benefit in younger children. Since 2023 new European restrictions apply after the review: the drug is not used in severe or uncontrolled hypertension or in severe renal impairment. AEMPS asks people to stop immediately and seek help in case of sudden severe headache, seizures, confusion or visual disturbance.

Sources

ICD-10: R09.8

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.

Common cold

Not recommended

Spanish «flu powders» – Frenadol, Pharmagrip, Gelocatil Gripe – are sachets and capsules where pseudoephedrine sits next to paracetamol, dextromethorphan and chlorphenamine. They do not shorten a cold. The 2012 Cochrane review rates such combinations as giving small benefit to adults and finds no benefit at all in young children. The risk meanwhile adds up across every component: paracetamol is easy to overdose when also taken separately, chlorphenamine causes drowsiness, and pseudoephedrine raises blood pressure and disturbs sleep. Spanish toxicologists in Anales de Pediatría 2022 described child poisonings with exactly these products. What works in a cold is rest, fluids and a painkiller as needed in a dose you can count. If a flu combination with pseudoephedrine was prescribed to a child or advised for a week, consider seeking a second opinion.

Sources

ICD-10: J00 · ICD-11: CA00

Weight loss

Not recommended

Pseudoephedrine is bought in gyms as a «fat burner» and pre-workout stimulant: it is a relative of ephedrine, which once stood in fat-burning blends. The drug is not registered for weight loss anywhere and that use has no evidence base. The AEMPS ficha técnica knows one indication – temporary relief of nasal congestion. The price of the experiment is known in advance: the drug is contraindicated in coronary disease, tachyarrhythmia, severe hypertension, hyperthyroidism and severe renal failure, and after the 2023 European review the label gained reversible cerebral vasoconstriction syndrome and posterior reversible encephalopathy syndrome – both about spasm of brain vessels. In sport, pseudoephedrine above a concentration threshold counts as doping. If pseudoephedrine was recommended for weight loss or «cutting», consider seeking a second opinion.

Sources

How to read tiers A–F

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

Mechanism of action

A stereoisomer of ephedrine. It acts as an agonist at alpha-1 adrenergic receptors and, to a lesser degree, at beta receptors: the vessels of the nasal lining narrow, swelling subsides and the nose opens – but unlike drops, the substance reaches the mucosa through the bloodstream, which means it acts on every other vessel too. That is where the whole side effect profile comes from: rising blood pressure, tachycardia, insomnia, anxiety. Absorption is fast and nearly complete, elimination is mainly renal and unchanged, and the half-life depends on urine pH. The two rare vascular syndromes for which the reviewed the drug in 2023 come from the same mechanism: cerebral artery spasm in reversible cerebral vasoconstriction and posterior brain edema in PRES.

Safety

Contraindications

Hypersensitivity to pseudoephedrine and other sympathomimetics
Coronary heart disease and tachyarrhythmias
Severe or uncontrolled arterial hypertension
Severe renal impairment, acute or chronic
Hyperthyroidism
Monoamine oxidase inhibitors now or within the past two weeks
Pregnancy and breastfeeding
Children under 12 years

Serious adverse effects

Reversible cerebral vasoconstriction syndrome
Posterior reversible encephalopathy syndrome (PRES)
Hypertensive crisis
Ischemic colitis and optic nerve ischemia
Hallucinations, especially at high doses, and confusion in children
Acute generalized exanthematous pustulosis

Common adverse effects

Insomnia and restlessness
Palpitations and tachycardia
Dry mouth
Headache
Nausea
Urinary retention in men with prostate enlargement

Pregnancy: can you take Pseudoephedrine?

Pseudoephedrine is contraindicated in pregnancy: animal studies do not predict the human response, and the vasoconstrictor action reaches uteroplacental blood flow as well.

Breastfeeding: can you take Pseudoephedrine?

A small amount passes into breast milk, about 0.5 percent of the dose over 24 hours. Something else matters more: reduced milk production has been described during use, so the drug is not taken while breastfeeding.

Calculate RID

Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.

Drug–drug interactions

1 pair found. Sorted from critical to minor.

CriticalSelegilineSelective irreversible MAO-B inhibitor

Mechanism

Selegiline irreversibly inhibits monoamine oxidase type B (MAO-B), and enzyme activity recovers only as new enzyme is made (selegiline summary of product characteristics, SmPC, section 5.2). After a single 10 mg dose, platelet MAO-B activity returns to normal in about 2 weeks (selegiline SmPC, section 5.2). Pseudoephedrine constricts blood vessels through alpha-1 adrenergic receptors. It also enters sympathetic nerve fibres, where it displaces noradrenaline from storage vesicles (pseudoephedrine SmPC, section 5.1). Monoamine oxidase (MAO) inhibitors, selegiline included, increase catecholamine release and can prolong and intensify the vasopressor and cardiac stimulant effects of pseudoephedrine (pseudoephedrine SmPC, section 4.5). Selegiline should not be combined with sympathomimetics because of the risk of hypertension (selegiline SmPC, section 4.5). Above the recommended 10 mg, it may lose its selectivity for MAO-B, which raises the risk of hypertension (selegiline SmPC, section 4.4).

Symptoms

According to the pseudoephedrine summary of product characteristics (SmPC), combining it with monoamine oxidase (MAO) inhibitors can cause severe hypertension, hyperpyrexia and headache (section 4.5). Uncontrolled hypertension, including hypertensive crisis, has been reported when the usual dose of selegiline was combined with ephedrine, of which pseudoephedrine is a stereoisomer (selegiline labels, US Food and Drug Administration, ; pseudoephedrine SmPC, section 5.1). Pseudoephedrine alone at the usual dose can raise blood pressure, cause tachycardia and stimulate the central nervous system (pseudoephedrine SmPC, section 4.4). Warning signs that call for stopping pseudoephedrine are hypertension, tachycardia, palpitations, arrhythmias, nausea, and new or worsening headache (pseudoephedrine SmPC, section 4.4).

Management

The combination is contraindicated. The selegiline summary of product characteristics (SmPC) rules it out (sections 4.3 and 4.5). The pseudoephedrine SmPC names selegiline among the monoamine oxidase inhibitors, or MAOIs (sections 4.3 and 4.5). The over-the-counter pseudoephedrine label of the US Food and Drug Administration () also rules out the combination. Selegiline should not be combined with any sympathomimetic, nasal decongestants included (selegiline SmPC, sections 4.3 and 4.5). Do not take pseudoephedrine within 2 weeks after stopping selegiline (pseudoephedrine SmPC, section 4.3; FDA pseudoephedrine label). Section 4.5 of the pseudoephedrine SmPC gives 15 days. Ask the patient to report all prescription and over-the-counter medicines they take or plan to take, especially cold medicines (FDA label of selegiline orally disintegrating tablets, section 17). Patients who are not sure whether a prescription drug is an MAOI are advised to check before taking pseudoephedrine (FDA pseudoephedrine label). Stop pseudoephedrine if hypertension, tachycardia, palpitations, arrhythmias, nausea or headache appear (pseudoephedrine SmPC, section 4.4). The patient should report severe headache, unusual new symptoms or very high blood pressure to a doctor straight away (FDA label of selegiline orally disintegrating tablets, section 17). Do not raise the dose of selegiline tablets or capsules above 10 mg a day (selegiline SmPC, sections 4.2 and 4.4; FDA selegiline capsules label).

Sources

Pair details →Selegiline →

Label mentions23 mentions

Verbatim lines from the interaction sections, in the language of the label

From this drug’s label

CriticalIMAOclass named in the label
«Pacientes que estén tomando o hayan tomado i nhibidores de la monoaminooxidasa (IMAO) en las dos semanas precedentes o durante las 2 semanas posteriores a la interrupción de dicho tratamiento El uso…»
AEMPS, section 4.3 · Open on CIMA
CriticalSelegiline
«Inhibidores de la monoaminooxidasa (IMAO): se debe evitar la administración conjunta de este medicamento e incluso en los 15 días posteriores a la finalización del tratamiento con IMAO…»
AEMPS, section 4.5 · Open on CIMA
CriticalTranylcypromine
«Inhibidores de la monoaminooxidasa (IMAO): se debe evitar la administración conjunta de este medicamento e incluso en los 15 días posteriores a la finalización del tratamiento con IMAO…»
AEMPS, section 4.5 · Open on CIMA
MajorCabergoline
«Historia de hemorragia cerebral o con factores de riesgo que puedan aumentar el riesgo de hemorragia cerebral. Esto se debe a la actividad alfa-mimética de pseudoefedrina, en asociación con otros…»
AEMPS, section 4.3 · Open on CIMA
MajorDihydroergotamine
«Historia de hemorragia cerebral o con factores de riesgo que puedan aumentar el riesgo de hemorragia cerebral. Esto se debe a la actividad alfa-mimética de pseudoefedrina, en asociación con otros…»
AEMPS, section 4.3 · Open on CIMA
MajorErgotamine
«Historia de hemorragia cerebral o con factores de riesgo que puedan aumentar el riesgo de hemorragia cerebral. Esto se debe a la actividad alfa-mimética de pseudoefedrina, en asociación con otros…»
AEMPS, section 4.3 · Open on CIMA
MajorMoclobemide
«Inhibidores de la monoaminooxidasa (IMAO): se debe evitar la administración conjunta de este medicamento e incluso en los 15 días posteriores a la finalización del tratamiento con IMAO…»
AEMPS, section 4.5 · Open on CIMA
MajorOxymetazoline
«Historia de hemorragia cerebral o con factores de riesgo que puedan aumentar el riesgo de hemorragia cerebral. Esto se debe a la actividad alfa-mimética de pseudoefedrina, en asociación con otros…»
AEMPS, section 4.3 · Open on CIMA
Moderateantidepresivos tricíclicosclass named in the label
«La administración oral de pseudoefedrina a la dosis recomendada puede causar otros efectos simpaticomiméticos, tales como aumento de la presión sanguínea, taquicardia o manifestaciones de excitación…»
AEMPS, section 4.4 · Open on CIMA
Moderateantihistamínicosclass named in the label
«La administración oral de pseudoefedrina a la dosis recomendada puede causar otros efectos simpaticomiméticos, tales como aumento de la presión sanguínea, taquicardia o manifestaciones de excitación…»
AEMPS, section 4.4 · Open on CIMA
Moderatebetabloqueantesclass named in the label
«Antihipertensivos o diuréticos usados como antihipertensivos : con algunos como los betabloqueantes, metildopa, reserpina y guanetidina puede haber una disminución de sus efectos antihipertensivos…»
AEMPS, section 4.5 · Open on CIMA
Moderatedigitálicosclass named in the label
«Glucósidos digitálicos: posible aumento de riesgo de arritmias cardiacas.»
AEMPS, section 4.5 · Open on CIMA
Moderatediuréticosclass named in the label
«Antihipertensivos o diuréticos usados como antihipertensivos : con algunos como los betabloqueantes, metildopa, reserpina y guanetidina puede haber una disminución de sus efectos antihipertensivos…»
AEMPS, section 4.5 · Open on CIMA
ModerateMethyldopa
«Antihipertensivos o diuréticos usados como antihipertensivos : con algunos como los betabloqueantes, metildopa, reserpina y guanetidina puede haber una disminución de sus efectos antihipertensivos…»
AEMPS, section 4.5 · Open on CIMA

From other drugs’ labels

CriticalTranylcypromine
«Combination with Certain Drugs: Sympathomimetic products (e.g., cold, hay fever or weight-reducing products that contain vasoconstrictors such as pseudoephedrine, phenylephrine, and ephedrine; or…»
FDA, section 4 · Open on DailyMed
MajorRasagiline
«Simpaticomiméticos: Con los inhibidores de la MAO, se han notificado interacciones medicamentosas con el empleo concomitante de medicaciones simpáticomiméticas. Por tanto, en vista de la actividad…»
AEMPS, section 4.5 · Open on CIMA
MajorTranylcypromine
«Influencia en el efecto de tranilcipromina: Se debe evitar la combinación con simpaticomiméticos directos como la dopamina o la pseudoefedrina (por ejemplo, en fármacos cardiovasculares para el…»
AEMPS, section 4.5 · Open on CIMA
ModerateAtomoxetine
«Medicamentos que actúan sobre la noradrenalina: Los medicamentos que actúen sobre la noradrenalina deben utilizarse con precaución cuando se administren conjuntamente con atomoxetina, puesto que…»
AEMPS, section 4.5 · Open on CIMA
ModerateSelegiline
«Sympathomimetic Amines and Buspirone: The use of EMSAM with sympathomimetic amines or buspirone may produce substantial elevations in blood pressure. Therefore, monitor blood pressure if EMSAM is…»
FDA, section 7 · Open on DailyMed
Cetirizine
«Debido a la farmacocinética, farmacodinamia y perfil de tolerancia de cetirizina, no se esperan interacciones con este antihistamínico. De hecho, no se han notificado ni interacciones…»
AEMPS, section 4.5 · Open on CIMA
Levocetirizine
«No se han realizado estudios de interacción con levocetirizina (incluyendo estudios con inductores de CYP3A4). Los estudios realizados con el compuesto racémico cetirizina demostraron que no había…»
AEMPS, section 4.5 · Open on CIMA
Levocetirizine
«DRUG INTERACTIONS: Antipyrine, Azithromycin, Cimetidine, Erythromycin, Ketoconazole, Theophylline, and Pseudoephedrine»
FDA, section 7 · Open on DailyMed
Linezolid
«Pacientes que tomen cualquiera de estos medicamentos: inhibidores de la recaptación de serotonina (ver sección 4.4), antidepresivos tricíclicos, agonistas del receptor 5 HT 1 de serotonina…»
AEMPS, section 4.3 · Open on CIMA

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Frequently asked

What is Pseudoephedrine used for?

Pseudoephedrine is evaluated for the following indications with varying evidence strength: Nasal congestion (evidence tier C), Common cold (evidence tier D), Weight loss (evidence tier F). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Pseudoephedrine?

Common side effects of Pseudoephedrine (≥ 1 in 100): Insomnia and restlessness, Palpitations and tachycardia, Dry mouth, Headache, Nausea, Urinary retention in men with prostate enlargement. See the Safety section for uncommon and serious reactions.

Is Pseudoephedrine safe during pregnancy?

Pseudoephedrine is contraindicated in pregnancy: animal studies do not predict the human response, and the vasoconstrictor action reaches uteroplacental blood flow as well.

Is Pseudoephedrine compatible with breastfeeding?

Who should not take Pseudoephedrine?

Pseudoephedrine is contraindicated in: Hypersensitivity to pseudoephedrine and other sympathomimetics; Coronary heart disease and tachyarrhythmias; Severe or uncontrolled arterial hypertension; Severe renal impairment, acute or chronic; Hyperthyroidism. Full list in the Safety section.

Official sources

Direct links to regulator labels. Open in a new tab.

AEMPS / CIMA

Other drugs in this group

Fluticasone furoate (nasal), Interferon alpha-2b (nasal formulations), Mometasone furoate (nasal), Oxymetazoline, Xylometazoline