Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
APRESAZIDE vs ALDORIL D30
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Apresazide is a combination of hydralazine, a direct-acting vasodilator that relaxes arteriolar smooth muscle, and hydrochlorothiazide, a thiazide diuretic that inhibits sodium and chloride reabsorption in the distal convoluted tubule.
Aldoril D30 is a combination of methyldopa, a centrally acting alpha-2 adrenergic agonist that reduces sympathetic outflow, and hydrochlorothiazide, a thiazide diuretic that inhibits the sodium-chloride symporter in the distal convoluted tubule, decreasing plasma volume and peripheral resistance.
Hypertension
Hypertension
1 capsule (hydralazine 25 mg / hydrochlorothiazide 25 mg) orally twice daily; may increase to 2 capsules twice daily if needed. Maximum: 4 capsules daily.
Oral: 1 tablet (hydrochlorothiazide 30 mg / methyldopa 500 mg) twice daily; maximum dose: 2 tablets twice daily.
Hydralazine: 2-4 hours (fast acetylators), 4-8 hours (slow acetylators); Hydrochlorothiazide: 6-15 hours. Clinical context: Dosing interval typically 12 hours for hydralazine component.
Terminal elimination half-life of hydrochlorothiazide is 6-15 hours; methyldopa half-life is 1.8 hours (normal renal function). In renal impairment, half-life of both components is prolonged.
Hydralazine: primarily hepatic acetylation by N-acetyltransferase; Hydrochlorothiazide: not extensively metabolized, eliminated renally.
Methyldopa is metabolized by conjugation (catechol-O-methyltransferase) and hepatic sulfation; hydrochlorothiazide is not extensively metabolized and is excreted unchanged by the kidney.
Hydralazine: ~75% renal (metabolites), <10% unchanged; Hydrochlorothiazide: >95% renal (unchanged).
Renal: approximately 50% as parent drug and metabolites; biliary/fecal: minimal, less than 5%.
Hydralazine: 85-90% (plasma proteins); Hydrochlorothiazide: 40-68% (albumin).
Methyldopa: <10% bound to plasma proteins; hydrochlorothiazide: 40-68% bound to albumin.
Hydralazine: 1.5 L/kg; Hydrochlorothiazide: 3-4 L/kg. Clinical meaning: Hydralazine distributes widely; Hydrochlorothiazide distributes into extracellular fluid.
Methyldopa: Vd 0.2-0.3 L/kg (distributes into tissues, crosses placenta); hydrochlorothiazide: Vd 0.75-1.5 L/kg (extensively distributed, does not cross blood-brain barrier significantly).
Hydralazine: 26-50% (oral, first-pass metabolism); Hydrochlorothiazide: 65-70% (oral).
Oral bioavailability of methyldopa is approximately 25% (variable, influenced by gut metabolism); hydrochlorothiazide bioavailability is 65-75%.
Contraindicated in anuria. For GFR 30-50 m L/min: reduce dose to 1 capsule daily. For GFR <30 m L/min: avoid use due to thiazide inefficacy.
GFR 30-60 m L/min: reduce dose by 50%; GFR <30 m L/min: not recommended.
Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50% (start with 1 capsule daily). Child-Pugh C: contraindicated.
Child-Pugh Class B or C: contraindicated; use not recommended.
Weight-based: hydralazine 0.75-1 mg/kg/dose every 6-12 hours (max 50 mg/dose); hydrochlorothiazide 1-2 mg/kg/day divided every 12 hours. Combination not recommended; adjust individual components.
Not recommended for use in pediatric patients due to lack of safety and efficacy data.
Start with 1 capsule daily; titrate slowly due to increased risk of hypotension and electrolyte imbalance. Monitor renal function and serum potassium.
Start with lowest dose; monitor for hypotension, electrolyte imbalance, and CNS effects; consider reduced initial dose.
None
None
May cause drug-induced lupus erythematosus (hydralazine),Peripheral neuritis (hydralazine),Electrolyte imbalances (hypokalemia, hyponatremia) due to hydrochlorothiazide,Sulfonamide hypersensitivity cross-reaction,Exacerbation or activation of systemic lupus erythematosus,Possible myocardial infarction or angina pectoris in patients with coronary artery disease
May cause hemolytic anemia, liver disorders, positive Coombs test, sedation, depression, and hypersensitivity reactions. Hydrochlorothiazide may cause electrolyte imbalance, hyperuricemia, photosensitivity, and exacerbation of systemic lupus erythematosus. Use with caution in renal impairment, hepatic disease, and in patients with a history of drug-induced hemolytic anemia.
Hypersensitivity to hydralazine, hydrochlorothiazide, or sulfonamides,Anuria,Acute myocardial infarction,Dissecting aortic aneurysm,Severe renal impairment (creatinine clearance <30 m L/min)
Active hepatic disease, history of previous methyldopa therapy-associated liver disorders; anuria; hypersensitivity to methyldopa, hydrochlorothiazide, or sulfonamide-derived drugs.
Avoid high-potassium foods if potassium-sparing effect is not desired (but hydrochlorothiazide causes potassium loss; monitor accordingly). Take with food to reduce GI upset. Avoid natural licorice as it may enhance potassium loss and worsen hypertension.
Food may decrease absorption of methyldopa. Avoid excessive intake of high-potassium foods (e.g., bananas, oranges) unless directed. Hydrochlorothiazide may cause potassium depletion; maintain adequate dietary potassium. Avoid natural licorice as it can worsen hypokalemia.
Apresazide is a fixed-dose combination of hydralazine and hydrochlorothiazide. Hydralazine: First trimester: limited data, no clear evidence of major malformations; second and third trimesters: risk of neonatal thrombocytopenia, lupus-like syndrome, and hypotension. Hydrochlorothiazide: First trimester: possible association with neural tube defects and oral clefts (weak); second and third trimesters: fetal or neonatal jaundice, thrombocytopenia, electrolyte imbalance, and possible growth restriction. Overall, use only if benefit outweighs risk.
First trimester: Limited data; no clear evidence of major malformations but methyldopa crosses placenta. Second and third trimesters: Associated with reduced placental perfusion; possible fetal bradycardia and neonatal hypotension. Hydrochlorothiazide may cause fetal/neonatal jaundice, thrombocytopenia, and electrolyte disturbances.
Hydralazine: excreted in breast milk in low amounts; M/P ratio not well established; considered compatible with caution. Hydrochlorothiazide: excreted in breast milk; may suppress lactation; risk of neonatal electrolyte disturbances. Avoid use during breastfeeding, especially with high doses.
Methyldopa is excreted in breast milk in low concentrations; M/P ratio approximately 0.2. Hydrochlorothiazide is excreted in minimal amounts; may suppress lactation. Consider risks versus benefits.
Hydralazine: dose may need downward adjustment in later pregnancy due to altered volume of distribution and increased clearance. Hydrochlorothiazide: avoid use in pregnancy; consider alternative diuretics. If used, dose adjustment not well defined but start at lowest effective dose. No standard pharmacokinetic-based adjustments.
Methyldopa: Pregnancy-induced plasma volume expansion may require dose titration; monitor blood pressure and adjust accordingly. Hydrochlorothiazide: Often avoided in pregnancy due to volume depletion risks; if used, monitor electrolytes and renal function, no pharmacokinetic data necessitate routine dose adjustment.
Combination product of hydralazine and hydrochlorothiazide. Monitor for lupus-like syndrome (especially with high hydralazine doses). Check electrolytes and renal function regularly. Use with caution in patients with coronary artery disease or high-output heart failure.
ALDORIL D30 combines methyldopa (central alpha-2 agonist) and hydrochlorothiazide (thiazide diuretic). Monitor for orthostatic hypotension, especially at initiation. Taper not needed for methyldopa but discontinue if fever or liver dysfunction occurs. Interferes with urinary catecholamine measurements (false elevation). Hydrochlorothiazide may cause hyponatremia, hypokalemia, and hyperglycemia; check electrolytes and glucose periodically.
Take exactly as prescribed, do not skip doses.,May cause dizziness or faintness, especially when rising from sitting or lying position.,Avoid sudden discontinuation; taper under medical supervision.,Report symptoms like joint pain, fever, chest pain, or rash immediately.,Limit alcohol intake as it can exacerbate hypotension.
Take exactly as prescribed, preferably with food to reduce stomach upset.,Rise slowly from sitting or lying down to prevent dizziness.,This drug may make you drowsy; avoid driving or operating machinery until you know how it affects you.,Report fever, unexplained fatigue, jaundice, or dark urine immediately.,Weigh yourself daily and report rapid weight gain or swelling.,Limit alcohol intake as it can increase side effects.,Do not use salt substitutes containing potassium without consulting your doctor.
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 APRESAZIDE vs ALDORIL D30, answered by our medical review team.
APRESAZIDE is a Antihypertensive that works by Apresazide is a combination of hydralazine, a direct-acting vasodilator that relaxes arteriolar smooth muscle, and hydrochlorothiazide, a thiazide diuretic that inhibits sodium and chloride reabsorption in the distal convoluted tubule.. ALDORIL D30 is a Antihypertensive Combination that works by Aldoril D30 is a combination of methyldopa, a centrally acting alpha-2 adrenergic agonist that reduces sympathetic outflow, and hydrochlorothiazide, a thiazide diuretic that inhibits the sodium-chloride symporter in the distal convoluted tubule, decreasing plasma volume and peripheral resistance.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between APRESAZIDE and ALDORIL D30 depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of APRESAZIDE is: 1 capsule (hydralazine 25 mg / hydrochlorothiazide 25 mg) orally twice daily; may increase to 2 capsules twice daily if needed. Maximum: 4 capsules daily.. The standard adult dose of ALDORIL D30 is: Oral: 1 tablet (hydrochlorothiazide 30 mg / methyldopa 500 mg) twice daily; maximum dose: 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 APRESAZIDE and ALDORIL D30 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. APRESAZIDE is classified as Category C. Apresazide is a fixed-dose combination of hydralazine and hydrochlorothiazide. Hydralazine: First trimester: limited data, no clear evidence of major malformations; second and thir. ALDORIL D30 is classified as Category C. First trimester: Limited data; no clear evidence of major malformations but methyldopa crosses placenta. Second and third trimesters: Associated with reduced placental perfusion; p. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.