CHLOROTHIAZIDE W/ RESERPINE
Clinical safety rating: safe
MAOIs can cause excitability and hypertension Can cause depression and suicidal ideation.
Chlorothiazide inhibits the Na+/Cl- cotransporter in the distal convoluted tubule, reducing sodium and water reabsorption. Reserpine depletes catecholamines from postganglionic sympathetic nerve endings by inhibiting the vesicular monoamine transporter (VMAT), leading to reduced peripheral vascular resistance and central nervous system depletion.
| Metabolism | Chlorothiazide: Not extensively metabolized; excreted unchanged in urine. Reserpine: Extensively metabolized in the liver via hydrolysis and conjugation; undergoes enterohepatic circulation. |
| Excretion | Chlorothiazide: primarily renal (90-95% unchanged via tubular secretion); Reserpine: hepatic metabolism, renal excretion of metabolites (60% as metabolites, <1% unchanged). |
| Half-life | Chlorothiazide: 1.5-2 hours; Reserpine: 50-100 hours (terminal, due to enterohepatic recirculation and tissue binding). |
| Protein binding | Chlorothiazide: 20-40% bound to albumin; Reserpine: >95% bound to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Chlorothiazide: 0.2-0.4 L/kg (confined to extracellular fluid); Reserpine: 8-10 L/kg (extensive tissue binding, particularly lipid-rich tissues). |
| Bioavailability | Chlorothiazide: oral 30-50% (luminal degradation and limited absorption); Reserpine: oral 50-60% (extensive first-pass hepatic metabolism). |
| Onset of Action | Chlorothiazide: oral diuresis within 2 hours; Reserpine: oral hypotensive effect within 3-6 hours. |
| Duration of Action | Chlorothiazide: diuresis lasts 6-12 hours; Reserpine: hypotensive effect persists 1-2 weeks after discontinuation due to irreversible vesicular monoamine depletion. |
Oral, 500 mg chlorothiazide / 0.125 mg reserpine once or twice daily. Maximum daily dose: 1000 mg chlorothiazide / 0.25 mg reserpine.
| Dosage form | TABLET |
| Renal impairment | GFR 30-50 mL/min: reduce dose by 50% or extend interval; GFR <30 mL/min: contraindicated. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: avoid use. |
| Pediatric use | Chlorothiazide: 10-20 mg/kg/day orally in 2 divided doses; reserpine: 0.005-0.02 mg/kg/day orally in 1-2 divided doses. Maximum pediatric dose: 375 mg chlorothiazide/0.05 mg reserpine per day. |
| Geriatric use | Initiate at lowest dose (250 mg chlorothiazide/0.1 mg reserpine daily). Monitor for orthostatic hypotension, electrolyte disturbances, and CNS depression. Adjust based on renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
MAOIs can cause excitability and hypertension Can cause depression and suicidal ideation.
| FDA category | Animal |
| Breastfeeding | Chlorothiazide: Excreted in breast milk in low amounts; M/P ratio not specified. Reserpine: Excreted in breast milk, may cause adverse effects in nursing infants (e.g., nasal congestion, lethargy). Use not recommended due to risk of neonatal effects. |
| Teratogenic Risk | First trimester: Limited data, but thiazide diuretics are generally avoided due to potential placental hypoperfusion. Second/third trimester: May cause electrolyte disturbances, fetal/neonatal jaundice, thrombocytopenia, and possible fetal/neonatal hypotension. Reserpine may increase risk of neonatal respiratory depression, nasal congestion, and lethargy. |
■ FDA Black Box Warning
Reserpine component: May increase risk of breast cancer in postmenopausal women (based on epidemiological studies); also associated with mental depression, especially in patients with a history of depression.
| Common Effects | Depression |
| Serious Effects |
["Hypersensitivity to chlorothiazide, reserpine, or sulfonamides","History of major depression or suicidal ideation (reserpine)","Active peptic ulcer disease or ulcerative colitis (reserpine increases gastric acid secretion)","Pheochromocytoma (reserpine may precipitate hypertensive crisis)","Anuria or severe renal impairment (chlorothiazide)"]
| Precautions | ["Electrolyte imbalance (hypokalemia, hyponatremia) with chlorothiazide","Orthostatic hypotension and bradycardia with reserpine","Depression risk with reserpine; avoid in patients with history of depression","Sulfonamide sensitivity cross-reactivity (chlorothiazide is a sulfonamide derivative)","May exacerbate systemic lupus erythematosus","Gout and hyperuricemia with chlorothiazide"] |
Loading safety data…
| Fetal Monitoring | Monitor maternal blood pressure, serum electrolytes (especially potassium, sodium, chloride), renal function, and blood glucose. Fetal monitoring for growth, amniotic fluid volume, and signs of distress. Neonatal monitoring for electrolyte imbalance, jaundice, thrombocytopenia, and respiratory depression. |
| Fertility Effects | Chlorothiazide: No direct evidence of impaired fertility. Reserpine: May cause menstrual irregularities and decreased libido in females; in males, may reduce seminal volume and sperm motility. Potential impact on ovulation and spermatogenesis. |