ALDOCLOR-150
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ALDOCLOR-150 (ALDOCLOR-150).
Aldoclor-150 is a combination of methyldopa and chlorothiazide. Methyldopa is a centrally acting alpha-2 adrenergic agonist that reduces sympathetic outflow, decreasing peripheral vascular resistance and blood pressure. Chlorothiazide is a thiazide diuretic that inhibits sodium reabsorption in the distal convoluted tubule, leading to increased excretion of sodium and water, reducing plasma volume and blood pressure.
| Metabolism | Methyldopa is metabolized primarily via conjugation and decarboxylation; chlorothiazide is not extensively metabolized and is excreted unchanged in urine. |
| Excretion | Renal excretion of unchanged drug accounts for approximately 50-60% of the administered dose; hepatic metabolism contributes the remainder, with metabolites excreted via bile and feces. Less than 2% is excreted unchanged in feces. |
| Half-life | Terminal elimination half-life is approximately 6-8 hours in patients with normal renal function. In patients with creatinine clearance <30 mL/min, half-life may be prolonged to 15-20 hours, necessitating dose adjustment. |
| Protein binding | Approximately 70-80% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Vd is approximately 0.3-0.5 L/kg, indicating distribution primarily in extracellular fluid and limited tissue binding. |
| Bioavailability | Oral bioavailability is approximately 70-80%; food does not significantly alter absorption. |
| Onset of Action | Oral: Therapeutic effect (antihypertensive) typically begins within 1-2 hours after single dose; peak effect at 4-6 hours. |
| Duration of Action | Antihypertensive effect persists for 12-24 hours after a single oral dose, supporting once-daily dosing. Duration may be shorter in patients with rapid drug clearance. |
| Molecular Weight | 271.49 |
ALDOCLOR-150 is a combination product containing 150 mcg of clonidine and 25 mg of chlorthalidone. The typical adult dose is one tablet orally once daily.
| Dosage form | TABLET |
| Renal impairment | Contraindicated in patients with GFR <30 mL/min. For GFR 30-50 mL/min, reduce frequency to every other day. For GFR >50 mL/min, no adjustment necessary. |
| Liver impairment | Child-Pugh Class A: No adjustment necessary. Child-Pugh Class B: Reduce dose by 50% or extend dosing interval. Child-Pugh Class C: Use is not recommended due to risk of hepatic encephalopathy and fluid retention. |
| Pediatric use | Not recommended for pediatric use due to lack of safety and efficacy data in patients under 18 years of age. |
| Geriatric use | Initiate at lower dose (e.g., half tablet) due to increased sensitivity to antihypertensive effects, risk of orthostatic hypotension, and impaired renal function. Monitor blood pressure and electrolytes closely. |
| 1st trimester | Avoid. Associated with cardiovascular defects, oral clefts, and neural tube defects. Use only if no alternative and benefits outweigh risks. |
| 2nd trimester | Avoid. Chronic use linked to preterm birth, intrauterine growth restriction, and oligohydramnios. Short-term use only if essential. |
| 3rd trimester | Avoid. High risk of premature closure of ductus arteriosus, persistent pulmonary hypertension, and oligohydramnios. Contraindicated after 30 weeks. |
Clinical note
Comprehensive clinical and safety monograph for ALDOCLOR-150 (ALDOCLOR-150).
| Placental transfer | Crosses placenta via passive diffusion; fetal concentrations approximate maternal levels. |
| Breastfeeding | Excreted into breast milk in low amounts; no adverse effects reported in infants. Use caution with maternal high doses or prolonged therapy; theoretical risk of infant hypertension. |
■ FDA Black Box Warning
None.
| Serious Effects |
History of asthma, urticaria, or allergic-type reactions after aspirin or NSAIDsPerioperative pain in CABG surgeryAdvanced renal diseaseActive gastrointestinal bleedingThird trimester of pregnancy
| Precautions | May cause sedation, dizziness, and orthostatic hypotension. Avoid abrupt discontinuation. Use with caution in patients with impaired renal function, liver disease, or history of depression. Monitor for electrolyte imbalance, especially hypokalemia, due to chlorothiazide component., Methyldopa may cause positive direct Coombs test, hemolytic anemia, and liver disorders. Discontinue if jaundice or liver abnormalities occur. |
| Food/Dietary | Avoid excessive potassium-rich foods (bananas, oranges, spinach) unless directed, as thiazide can cause potassium loss; however, monitor for hypokalemia. Limit sodium intake to enhance antihypertensive effect. Methyldopa absorption is not significantly affected by food. |
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| Lactation Rating | L2 (Probably Compatible) |
| Teratogenic Risk | First trimester: Increased risk of neural tube defects (spina bifida) and other major congenital malformations (e.g., cardiovascular, orofacial clefts) due to folate antagonism. Second and third trimesters: Risk of intrauterine growth restriction (IUGR), oligohydramnios, and renal dysplasia. Neonatal: Folate deficiency, megaloblastic anemia, and potential for methotrexate-like toxicity if used near term. |
| Fetal Monitoring | Maternal: Complete blood count (CBC) for anemia, leukopenia, thrombocytopenia; liver and renal function tests; folic acid levels; urinalysis for crystalluria. Fetal: Serial ultrasound for growth restriction, oligohydramnios, and congenital anomalies; Doppler studies if IUGR suspected; detailed anatomy scan at 18-20 weeks. |
| Fertility Effects | Potential for impaired fertility due to folate antagonism affecting spermatogenesis and oogenesis; may cause reversible sperm abnormalities and ovulatory dysfunction. Folic acid supplementation is recommended to mitigate these effects. Data limited, but caution advised for individuals planning conception. |
| Clinical Pearls | ALDOCLOR-150 combines chlorothiazide (a thiazide diuretic) and methyldopa (a central alpha-2 agonist). Monitor for hypokalemia and hyponatremia due to thiazide; methyldopa may cause positive Coombs test (hemolytic anemia risk) and hepatotoxicity. Titrate methyldopa slowly to avoid sedation. Use with caution in renal impairment (CrCl <30 mL/min reduces thiazide efficacy). |
| Patient Advice | Take medication exactly as prescribed, usually once or twice daily. · May cause dizziness or drowsiness; avoid driving until effects are known. · Stand up slowly to prevent falls from low blood pressure. · Report unexplained fever, fatigue, or jaundice (signs of liver issues). · Avoid alcohol, which enhances sedative effects. · Do not stop abruptly (risk of rebound hypertension). |