Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
AZOR vs ALDORIL 15
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Amlodipine is a dihydropyridine calcium channel blocker that inhibits calcium ion influx across cardiac and vascular smooth muscle cells, causing vasodilation and reduced peripheral vascular resistance. Olmesartan is an angiotensin II receptor blocker (ARB) that selectively blocks AT1 receptors, inhibiting vasoconstriction and aldosterone secretion.
Methyldopa is a centrally acting alpha-2 adrenergic agonist that reduces sympathetic outflow from the brainstem, decreasing peripheral vascular resistance and blood pressure. Hydrochlorothiazide is a thiazide diuretic that inhibits sodium and chloride reabsorption in the distal convoluted tubule, reducing plasma volume and cardiac output.
Treatment of hypertension, alone or with other antihypertensive agents
Hypertension
AZOR is a combination of amlodipine and olmesartan. Typical adult dose: one tablet orally once daily. Available strengths: amlodipine/olmesartan 5mg/20mg, 5mg/40mg, 10mg/20mg, 10mg/40mg. Dose can be titrated based on blood pressure response.
1 tablet (hydrochlorothiazide 15 mg, methyldopa 250 mg) orally twice daily; increase as needed up to 2 tablets twice daily.
Amlodipine: 30-50 h (terminal); supports once-daily dosing. Olmesartan: 10-15 h (terminal); once-daily dosing effective
Terminal half-life: 12–17 hours; clinical context: steady-state achieved within 2–3 days; effect persists 12–24 hours
Amlodipine is extensively metabolized in the liver via CYP3A4 to inactive metabolites. Olmesartan is metabolized by the liver to a minor extent; it undergoes glucuronidation and some oxidation by CYP2C9.
Methyldopa is metabolized in the liver via conjugation and O-methylation; active metabolites include methyldopamine and methylnorepinephrine. Hydrochlorothiazide is not significantly metabolized and is excreted unchanged in urine.
Renal: 90% (amlodipine: 60% as metabolites, 10% as parent; olmesartan: 35-50% as parent via urine, rest in feces via bile). Fecal: 10%
Renal: ~70% unchanged; biliary/fecal: ~30% as metabolites
Amlodipine: ~93% bound to plasma proteins. Olmesartan: >99% bound to albumin
~90%, primarily to albumin
Amlodipine: 21 L/kg (large, extensive tissue distribution). Olmesartan: 17-30 L (approximate, Vd not typically reported per kg); distribution into tissues
2–4 L/kg; clinical meaning: extensive tissue distribution, concentrating in vascular smooth muscle
Oral: amlodipine 64-90% (high, first-pass ~10%); olmesartan 26% (oral, complete absorption reduced by first-pass ester hydrolysis)
Oral: 50–60% (extensive first-pass metabolism)
No dose adjustment is required for mild to moderate renal impairment (Cr Cl ≥30 m L/min). For severe renal impairment (Cr Cl <30 m L/min), use with caution; maximum dose of olmesartan is 20 mg once daily. Monitor serum potassium and creatinine.
GFR 30-50 m L/min: maximum 1 tablet twice daily. GFR <30 m L/min: avoid use.
No dose adjustment for mild hepatic impairment (Child-Pugh A). For moderate to severe hepatic impairment (Child-Pugh B or C), amlodipine half-life is prolonged; initiate with amlodipine 2.5 mg and olmesartan 10 mg, and titrate slowly. Use caution; contraindicated in severe hepatic impairment with cholestasis? Not specifically contraindicated but not recommended.
Child-Pugh A: caution, reduce dose. Child-Pugh B: avoid. Child-Pugh C: contraindicated.
Safety and efficacy in pediatric patients <18 years have not been established. Not recommended for use in children.
Not recommended for pediatric use; safety in children under 12 years not established.
In elderly patients (≥65 years), start with the lowest available dose (amlodipine/olmesartan 5/20 mg daily) and titrate slowly due to increased sensitivity and potential for hypotension. Monitor renal function and electrolytes closely in geriatric patients.
Start with 1 tablet once daily; monitor for hypotension and electrolyte imbalance. Reduce initial dose by 50%.
None
None
Fetal toxicity (detectable in second and third trimesters): drugs acting on the renin-angiotensin system can cause oligohydramnios, fetal renal dysfunction, and death,Avoid concomitant use with aliskiren in patients with diabetes,Hypotension in volume/depleted patients,Increased angina or myocardial infarction with calcium channel blockers, particularly with severe obstructive coronary artery disease,Peripheral edema is dose-dependent and more common with amlodipine,Hepatic impairment: lower starting dose,Renal artery stenosis,Electrolyte imbalances
Sedation, usually transient; may impair ability to drive or operate heavy machinery.,Positive Coombs test with hemolytic anemia (rare); monitor hematocrit and Coombs test.,Hepatotoxicity (hepatic necrosis) with fever, jaundice; discontinue if liver abnormalities occur.,Fluid and electrolyte imbalance (hypokalemia, hyponatremia, hypercalcemia) due to thiazide.,May precipitate gout in hyperuricemic patients.,May exacerbate systemic lupus erythematosus.
Hypersensitivity to any component,Do not use with aliskiren in patients with diabetes
Active hepatic disease (e.g., acute hepatitis, cirrhosis),Prior methyldopa therapy associated with liver disorders,Hypersensitivity to methyldopa or hydrochlorothiazide,Anuria,Sulfonamide allergy (cross-sensitivity with thiazides)
Avoid grapefruit and grapefruit juice due to CYP3A4 inhibition increasing amlodipine levels. No other significant food interactions.
Avoid high-sodium foods as they can reduce antihypertensive efficacy. Thiazides may cause hypokalemia; increase dietary potassium (bananas, orange juice) unless contraindicated. Alcohol may enhance orthostatic hypotension.
Pregnancy Category D. First trimester: Potential for fetal toxicity (oligohydramnios, fetal/neonatal renal dysfunction, skull hypoplasia) due to olmesartan action on renin-angiotensin system; avoid use. Second trimester: Continued risk of fetal renal impairment and oligohydramnios. Third trimester: High risk of fetal/neonatal renal failure, hypotension, hyperkalemia, and skull ossification defects; contraindicated.
First trimester: No increased risk of major malformations based on limited human data; animal studies show no teratogenicity at clinically relevant doses. Second/third trimesters: Fetal and neonatal adverse effects including oligohydramnios, fetal renal dysfunction, skull ossification delay, and hypotension in the neonate. Avoid use after 20 weeks gestation unless no alternative.
No human data on olmesartan or amlodipine excretion in breast milk. Amlodipine transfers into human milk with M/P ratio approximately 0.5-1.5; risk to infant unknown. Due to potential for adverse effects (hypotension, renal impairment), use is not recommended. Alternative antihypertensives with more safety data should be considered.
Methyldopa and hydrochlorothiazide are excreted into human milk. M/P ratio for methyldopa is approximately 0.5-1.0; for hydrochlorothiazide, M/P ratio ~2.0. Methyldopa is considered compatible with breastfeeding. Hydrochlorothiazide may suppress lactation and cause neonatal electrolyte disturbances. Use with caution; monitor infant for signs of diuresis or electrolyte imbalance.
Not applicable; use is contraindicated in pregnancy. No dose adjustment can mitigate fetal risk; alternative agents (e.g., labetalol, nifedipine) are preferred. If inadvertently used, discontinue as soon as pregnancy is detected.
Pharmacokinetic changes in pregnancy may include increased volume of distribution and enhanced renal clearance. No specific dose adjustment routine is recommended; dosing should be guided by clinical response. Methyldopa starting dose 250 mg twice daily, titrated to effect. Hydrochlorothiazide dose not typically adjusted, but caution due to potential volume depletion.
AZOR is a fixed-dose combination of amlodipine (calcium channel blocker) and olmesartan (angiotensin II receptor blocker). Monitor serum potassium and creatinine, especially in renal impairment or concomitant ACE inhibitor use. Avoid in pregnancy (use effective contraception). May cause dizziness or peripheral edema, often dose-related.
Aldoril 15 (methyldopa 250mg + hydrochlorothiazide 15mg) is rarely used due to superior alternatives. Monitor for hepatotoxicity, hemolytic anemia, and lupus-like syndrome. Titrate slowly to avoid sedation. Contraindicated in active liver disease, pheochromocytoma, and anuria.
Take exactly as prescribed, usually once daily, with or without food.,Avoid grapefruit or grapefruit juice as it can increase amlodipine levels.,Notify your doctor if you become pregnant or plan to become pregnant.,Do not stop taking suddenly; consult your doctor before discontinuing.,Report lightheadedness, fainting, or significant swelling in your ankles or feet.,Use caution when driving or operating machinery until you know how this medication affects you.
May cause drowsiness; avoid driving until tolerance develops.,Report unexplained fever, jaundice, or dark urine immediately.,Take at bedtime to minimize sedation.,Avoid sudden discontinuation; follow prescribed tapering schedule.,Use sun protection; thiazides increase photosensitivity.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about AZOR vs ALDORIL 15, answered by our medical review team.
AZOR is a Antihypertensive Combination that works by Amlodipine is a dihydropyridine calcium channel blocker that inhibits calcium ion influx across cardiac and vascular smooth muscle cells, causing vasodilation and reduced peripheral vascular resistance. Olmesartan is an angiotensin II receptor blocker (ARB) that selectively blocks AT1 receptors, inhibiting vasoconstriction and aldosterone secretion.. ALDORIL 15 is a Antihypertensive Combination that works by Methyldopa is a centrally acting alpha-2 adrenergic agonist that reduces sympathetic outflow from the brainstem, decreasing peripheral vascular resistance and blood pressure. Hydrochlorothiazide is a thiazide diuretic that inhibits sodium and chloride reabsorption in the distal convoluted tubule, reducing plasma volume and cardiac output.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between AZOR and ALDORIL 15 depend on the specific clinical indication. These are both Antihypertensive Combination agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of AZOR is: AZOR is a combination of amlodipine and olmesartan. Typical adult dose: one tablet orally once daily. Available strengths: amlodipine/olmesartan 5mg/20mg, 5mg/40mg, 10mg/20mg, 10mg/40mg. Dose can be titrated based on blood pressure response.. The standard adult dose of ALDORIL 15 is: 1 tablet (hydrochlorothiazide 15 mg, methyldopa 250 mg) orally twice daily; increase as needed up to 2 tablets twice daily.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between AZOR and ALDORIL 15 in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. AZOR is classified as Category C. Pregnancy Category D. First trimester: Potential for fetal toxicity (oligohydramnios, fetal/neonatal renal dysfunction, skull hypoplasia) due to olmesartan action on renin-angioten. ALDORIL 15 is classified as Category C. First trimester: No increased risk of major malformations based on limited human data; animal studies show no teratogenicity at clinically relevant doses. Second/third trimesters: . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.