Fixed-dose combination: angiotensin II receptor blocker plus thiazide diuretic
ATC code: C09DA01 (Losartan and diuretics)
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.
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.
Opens the checker prefilled with this drug. Pick the second one from your regimen.
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).
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.
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.
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.
FDA category D. 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).
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.
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.