SERPASIL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SERPASIL (SERPASIL).
Reserpine (Serpasil) is an indole alkaloid that depletes catecholamines (norepinephrine, dopamine) and serotonin from central and peripheral nerve endings by irreversibly binding to and inhibiting the vesicular monoamine transporter (VMAT), preventing storage of monoamines in presynaptic vesicles, leading to depletion and reduced sympathetic outflow.
| Metabolism | Reserpine is extensively metabolized in the liver via hydrolysis and glucuronidation; specific CYP enzymes are not well characterized. |
| Excretion | Primarily renal (approx. 60% unchanged and metabolites), biliary/fecal (approx. 40%), enterohepatic circulation negligible. |
| Half-life | Terminal elimination half-life 45–168 hours (mean 100 h), reflecting prolonged adrenergic depletion; clinical effects persist beyond serum presence. |
| Protein binding | ~96% bound to plasma proteins (albumin and lipoproteins). |
| Volume of Distribution | Vd 9.4 L/kg, indicating extensive tissue binding (particularly adrenergic neurons, brain, adipose). |
| Bioavailability | Oral: 30–40% due to extensive first-pass metabolism; IM/IV: 100%. |
| Onset of Action | Oral: 3–6 days for antihypertensive effect; IM: 2–4 hours; IV: 30–60 minutes. |
| Duration of Action | Oral: 1–6 weeks after discontinuation due to neuronal depletion kinetics; IM/IV: 4–12 hours (single dose). |
Hypertension: 0.1–0.25 mg orally once daily; initial dose 0.1 mg, maximum 0.5 mg/day. Psychosis (not first-line): 0.5–2 mg orally daily.
| Dosage form | ELIXIR |
| Renal impairment | No specific dose adjustment; use cautiously in severe renal impairment (CrCl <30 mL/min) due to risk of hypotension and CNS effects. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: avoid use due to risk of hepatic encephalopathy. |
| Pediatric use | Hypertension: 0.02 mg/kg/day orally divided every 6–12 hours; maximum 0.25 mg/day. Psychosis: not recommended. |
| Geriatric use | Initiate at 0.05 mg orally once daily; increase slowly due to increased sensitivity and risk of hypotension, sedation, and depression. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for SERPASIL (SERPASIL).
| Breastfeeding | Reserpine is excreted into breast milk. M/P ratio not established. Risk of infant bradycardia, GI upset, and nasal congestion. Not recommended during breastfeeding. |
| Teratogenic Risk | Reserpine (Serpasil) crosses the placenta. First trimester: no clear evidence of major malformations but risk of fetal bradycardia and hypothermia. Second and third trimesters: risk of neonatal bradycardia, hypotonia, lethargy, and respiratory depression. Use only if benefits outweigh risks. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to reserpine or any component","History of depression (especially suicidal)","Active peptic ulcer disease","Ulcerative colitis","Electroconvulsive therapy (within 7-14 days)","Concurrent MAO inhibitor therapy (or within 2 weeks of discontinuation)","Pheochromocytoma"]
| Precautions | ["May cause severe depression with risk of suicide (discontinue if depression occurs)","Use with caution in patients with history of peptic ulcer disease (increases gastric acid secretion)","Use with caution in patients with renal impairment (may reduce renal blood flow)","Avoid concomitant use with MAOIs (risk of hypertensive crisis)","Electroshock therapy: discontinue reserpine 7-14 days prior","May cause biliary colic in patients with gallstones","May exacerbate arrhythmias in patients with cardiac disease"] |
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| Monitor maternal blood pressure and fetal heart rate. Assess for signs of neonatal bradycardia and hypotonia after delivery. |
| Fertility Effects | Reserpine may cause galactorrhea and amenorrhea in females; decreased libido and impaired ejaculation in males. No clear effect on fertility. |