Evigrade

Losartan + Hydrochlorothiazide

Fixed-dose combination: angiotensin II receptor blocker plus thiazide diuretic

ATC code: C09DA01(Losartan and diuretics)

Updated · Methodology

Indications

A

Hypertension

Second line

Essential hypertension uncontrolled on losartan monotherapy. Per ESH/ 2023 and SEH-LELHA 2023 – second-line. Dose: 50/12.5, 100/12.5, 100/25 mg once daily. Full effect at 3 weeks. Losartan's uricosuric effect makes the combination acceptable in patients with prior gout (with caution), unlike other ARB-thiazide pairs.

ICD-10: I10 · ICD-11: BA00

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

Losartan selectively blocks AT1 receptors of angiotensin II; the active metabolite E-3174 produces long-lasting A-II suppression. Hydrochlorothiazide acts through the thiazide-sensitive NaCl cotransporter in distal tubules to excrete sodium, chloride, and water. Losartan also has a uricosuric effect that partly offsets thiazide-induced hyperuricemia.

Safety

Contraindications

  • Hypersensitivity to sartan, thiazides, or sulfonamides
  • Pregnancy (2nd-3rd trimester)
  • Bilateral renal artery stenosis
  • Severe renal impairment (CrCl <30 for the thiazide component)
  • Severe hepatic impairment, cholestasis
  • Hypokalemia, hypercalcemia, symptomatic hyperuricemia
  • Concomitant aliskiren in diabetes or CrCl <60

Serious adverse effects

  • Acute kidney injury (bilateral renal artery stenosis)
  • Angioedema
  • Severe hyperkalemia
  • Thiazide photosensitivity

Common adverse effects

  • Dizziness
  • Hypotension
  • Hyperkalemia
  • Hyponatremia
  • Hyperuricemia
  • Elevated creatinine
  • Cough (less than with ACE inhibitors)

Pregnancy: can you take Losartan + Hydrochlorothiazide?

Contraindicated from the 2nd trimester. ARBs and ACE inhibitors cause fetopathy: oligohydramnios, fetal renal failure, skull hypoplasia, limb contractures. In women of reproductive age planning pregnancy, switch in advance to methyldopa, labetalol, or slow-release nifedipine (ACOG 222 (2020), SEGO 2023).

Breastfeeding: can you take Losartan + Hydrochlorothiazide?

Milk excretion data for the fixed combination are limited. For breastfeeding ESH 2023 and ACOG 2020 recommend switching to enalapril (RID 0.2%), captopril (RID 0.02%), methyldopa, or labetalol.

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

Practical notes

Monitoring

K+, creatinine, uric acid at 2 weeks and yearly thereafter.

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Frequently asked

What is Losartan + Hydrochlorothiazide used for?

Losartan + Hydrochlorothiazide is evaluated for the following indications with varying evidence strength: Hypertension (evidence tier A). See the full indication matrix with dosing and citations above on this page.

What are the side effects of Losartan + Hydrochlorothiazide?

Common side effects of Losartan + Hydrochlorothiazide (≥ 1 in 100): Dizziness, Hypotension, Hyperkalemia, Hyponatremia, Hyperuricemia, Elevated creatinine. See the Safety section for uncommon and serious reactions.

Is Losartan + Hydrochlorothiazide safe during pregnancy?

Contraindicated from the 2nd trimester. ARBs and ACE inhibitors cause fetopathy: oligohydramnios, fetal renal failure, skull hypoplasia, limb contractures. In women of reproductive age planning pregnancy, switch in advance to methyldopa, labetalol, or slow-release nifedipine (ACOG 222 (2020), SEGO 2023).

Is Losartan + Hydrochlorothiazide compatible with breastfeeding?

Milk excretion data for the fixed combination are limited. For breastfeeding ESH 2023 and ACOG 2020 recommend switching to enalapril (RID 0.2%), captopril (RID 0.02%), methyldopa, or labetalol.

Who should not take Losartan + Hydrochlorothiazide?

Losartan + Hydrochlorothiazide is contraindicated in: Hypersensitivity to sartan, thiazides, or sulfonamides; Pregnancy (2nd-3rd trimester); Bilateral renal artery stenosis; Severe renal impairment (CrCl <30 for the thiazide component); Severe hepatic impairment, cholestasis. Full list in the Safety section.

Other drugs in this group

Olmesartan medoxomil, Olmesartan + Hydrochlorothiazide, Perindopril + Indapamide, Ramipril, Sacubitril + Valsartan, Amlodipine + Olmesartan, Azilsartan medoxomil + chlorthalidone, Enalapril