Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ALDOCLOR-250 vs CARDURA
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Aldoclor-250 is a combination of methyldopa and chlorothiazide. Methyldopa is a centrally acting alpha-2 adrenergic agonist that reduces sympathetic outflow from the brain, decreasing peripheral vascular resistance and blood pressure. Chlorothiazide is a thiazide diuretic that inhibits sodium and chloride reabsorption in the distal convoluted tubule, increasing urinary output and reducing plasma volume.
Selective antagonist of alpha-1 adrenergic receptors, causing relaxation of smooth muscle in blood vessels and prostate.
Hypertension (first-line or adjunctive therapy),Off-label: Management of hypertensive crisis (as part of combination therapy)
Hypertension,Benign prostatic hyperplasia
250 mg orally twice daily
Initial: 1 mg orally once daily, titrated based on standing blood pressure response up to 16 mg daily as a single dose or divided twice daily. Maximum: 16 mg/day.
1.5-3 hours; prolonged in renal impairment (up to 20 hours with Cr Cl <10 m L/min).
Terminal elimination half-life is approximately 22 hours, allowing once-daily dosing; peak effect on blood pressure occurs at 2-6 hours post-dose.
Methyldopa: Primarily hepatic metabolism via catecholamine pathways; conjugated to sulfate and other metabolites. Chlorothiazide: Not extensively metabolized; excreted unchanged in urine.
Extensively metabolized in the liver via O-demethylation and hydroxylation; CYP3A4 is the major enzyme involved.
Renal (70-80% unchanged), biliary/fecal (15-25% as metabolites); total clearance ~250 m L/min.
Primarily hepatic metabolism (approx. 60-70%) with biliary excretion of metabolites; renal excretion accounts for about 30-40% of the dose, mainly as metabolites with <5% unchanged drug.
25-40% bound primarily to albumin and alpha-1-acid glycoprotein.
98-99% bound to plasma proteins (primarily albumin).
0.6-1.0 L/kg; indicates distribution into total body water and some tissue binding.
0.5-1.0 L/kg (approximately 50-70 L in adults); indicates extensive extravascular distribution.
70-90% (oral); 100% (IV).
Oral bioavailability is approximately 65% (range 43-81%) with minimal first-pass effect.
Cr Cl >50 m L/min: no adjustment; Cr Cl 10-50 m L/min: 250 mg once daily; Cr Cl <10 m L/min: 250 mg every 48 hours
No dose adjustment required for GFR ≥30 m L/min. For GFR <30 m L/min, start with 0.5 mg daily and titrate cautiously due to increased sensitivity.
Child-Pugh A: no adjustment; Child-Pugh B: use with caution, reduce dose by 50%; Child-Pugh C: avoid use
Child-Pugh A: Start at 0.5 mg daily. Child-Pugh B or C: Contraindicated due to extensive hepatic metabolism.
Not recommended for use in pediatric patients due to lack of safety and efficacy data
Safety and efficacy not established in pediatric patients; use not recommended.
Start at lower end of dosing range; monitor renal function closely; adjust dose based on Cr Cl
Initiate at 0.5 mg daily due to increased risk of orthostatic hypotension. Titrate slowly based on tolerability and response.
None explicitly listed. However, methyldopa carries a warning for hepatotoxicity and hemolytic anemia; chlorothiazide carries a warning for electrolyte disturbances and hypersensitivity reactions.
None
Hepatotoxicity (methyldopa), hemolytic anemia, positive direct Coombs test, sedation, depression, bradycardia, orthostatic hypotension, electrolyte imbalance (hypokalemia, hyponatremia, hypomagnesemia), hyperuricemia, hyperglycemia, photosensitivity, lupus-like syndrome, and hypersensitivity reactions.
Orthostatic hypotension and syncope, especially with first dose,Use with caution in patients with hepatic impairment,Risk of priapism,Intraoperative floppy iris syndrome during cataract surgery
Active hepatic disease, history of previous methyldopa-induced liver dysfunction, hemolytic anemia associated with methyldopa, anuria, hypersensitivity to methyldopa, chlorothiazide, or sulfonamide-derived drugs, severe renal impairment (Cr Cl <30 m L/min), and concomitant therapy with MAO inhibitors.
Hypersensitivity to doxazosin or other quinazolines
Avoid high-potassium foods (bananas, oranges, spinach) unless specifically advised; chlorothiazide may cause potassium loss, but methyldopa can cause potassium retention. Avoid excessive alcohol intake as it may potentiate hypotension. Take with food to reduce gastrointestinal upset. May decrease glucose tolerance; monitor in diabetic patients.
Avoid grapefruit and grapefruit juice as they may increase doxazosin levels. Take with food to reduce gastrointestinal upset. No other significant food interactions.
FDA Pregnancy Category D. First trimester: Associated with cardiovascular defects (e.g., VSD), neural tube defects, and oral clefts. Second and third trimesters: Fetal nephrotoxicity (oligohydramnios, renal failure), premature closure of ductus arteriosus, pulmonary hypertension, and intracranial hemorrhage. Avoid in third trimester.
Pregnancy Category C. First trimester: No evidence of teratogenicity in animal studies; limited human data. Second/third trimesters: Potential risk of fetal hypotension and hypoxia from maternal hypotension. Avoid use in pregnancy unless benefit outweighs risk.
Chlorothiazide is excreted in breast milk; M/P ratio unknown. Can suppress lactation. Use only if maternal benefit outweighs potential infant risks (e.g., electrolyte disturbances, thrombocytopenia).
Excreted in human milk; M/P ratio unknown. Caution due to potential for hypotension in nursing infants. Use only if essential.
Increased volume of distribution and GFR in pregnancy may necessitate higher doses for equivalent effect. Start at lowest effective dose; titrate based on BP response. Monitor for hypokalemia and metabolic alkalosis.
No established dose adjustments for pregnancy; use lowest effective dose due to potential for increased clearance and changes in volume of distribution.
Aldoclor-250 is a combination of methyldopa (250mg) and chlorothiazide. Methyldopa can cause a positive direct Coombs test (10-20% of patients) which may interfere with blood cross-matching; obtain a hematocrit and Coombs test before therapy and at 6 and 12 months. Chlorothiazide may cause hypokalemia; monitor potassium and consider potassium supplementation. Onset of methyldopa is 3-6 hours; delay full effect for 48-72 hours. Avoid use in patients with active liver disease or history of previous methyldopa-induced liver dysfunction.
CARDURA (doxazosin) is an alpha-1 blocker used for hypertension and benign prostatic hyperplasia (BPH). First-dose syncope is more common with immediate-release (IR) than extended-release (GITS). Start IR at 1 mg at bedtime and titrate slowly. GITS formulation minimizes orthostatic effects. Monitor blood pressure carefully in elderly patients. May cause intraoperative floppy iris syndrome (IFIS) during cataract surgery; do not stop therapy preoperatively. Avoid use in patients with orthostatic hypotension or micturition syncope.
Take exactly as prescribed; do not skip doses or stop suddenly.,May cause drowsiness or dizziness; avoid driving or operating machinery until you know how it affects you.,Rise slowly from sitting or lying to prevent lightheadedness.,Report any unexplained fever, jaundice, or dark urine immediately.,Use sun protection; this drug may increase sensitivity to sunlight.,Do not use potassium supplements or salt substitutes without consulting your doctor.,If you miss a dose, take it as soon as you remember unless it's near the next dose; do not double.
Take the first dose at bedtime to minimize dizziness. Sit or lie down if you feel lightheaded.,Avoid sudden position changes; rise slowly from sitting or lying positions.,May cause dizziness, drowsiness, or blurred vision. Do not drive until you know how CARDURA affects you.,For BPH, it may take up to 2 weeks to improve symptoms. Do not stop medication abruptly.,Inform your surgeon if you are scheduled for cataract surgery; CARDURA may affect eye surgery outcomes.,Avoid alcohol, which can worsen side effects like dizziness and low blood pressure.,For hypertension, continue regular monitoring with your healthcare provider.
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 ALDOCLOR-250 vs CARDURA, answered by our medical review team.
ALDOCLOR-250 is a Antihypertensive Combination (Central Alpha Agonist and Thiazide Diuretic) that works by Aldoclor-250 is a combination of methyldopa and chlorothiazide. Methyldopa is a centrally acting alpha-2 adrenergic agonist that reduces sympathetic outflow from the brain, decreasing peripheral vascular resistance and blood pressure. Chlorothiazide is a thiazide diuretic that inhibits sodium and chloride reabsorption in the distal convoluted tubule, increasing urinary output and reducing plasma volume.. CARDURA is a Alpha-1 Blocker Antihypertensive that works by Selective antagonist of alpha-1 adrenergic receptors, causing relaxation of smooth muscle in blood vessels and prostate.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ALDOCLOR-250 and CARDURA 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 ALDOCLOR-250 is: 250 mg orally twice daily. The standard adult dose of CARDURA is: Initial: 1 mg orally once daily, titrated based on standing blood pressure response up to 16 mg daily as a single dose or divided twice daily. Maximum: 16 mg/day.. 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 ALDOCLOR-250 and CARDURA 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. ALDOCLOR-250 is classified as Category C. FDA Pregnancy Category D. First trimester: Associated with cardiovascular defects (e.g., VSD), neural tube defects, and oral clefts. Second and third trimesters: Fetal nephrotoxici. CARDURA is classified as Category C. Pregnancy Category C. First trimester: No evidence of teratogenicity in animal studies; limited human data. Second/third trimesters: Potential risk of fetal hypotension and hypoxia. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.