SERPASIL
Clinical safety rating
cautionComprehensive 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). |
| Molecular Weight | 608.69 |
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 | Avoid. Associated with increased risk of congenital malformations, particularly neural tube defects and cardiac anomalies. |
| 2nd trimester | Avoid. May cause fetal bradycardia, hypotension, and hypoperfusion. |
| 3rd trimester | Avoid. Use near term may cause neonatal respiratory depression, bradycardia, and hypotonia. |
Clinical note
Comprehensive clinical and safety monograph for SERPASIL (SERPASIL).
| Placental transfer | Reserpine crosses the placenta readily, achieving fetal plasma concentrations similar to maternal levels. |
| Breastfeeding | Reserpine is excreted into breast milk in small amounts. However, due to potential for serious adverse effects such as galactorrhea, nasal congestion, and respiratory depression in the infant, breastfeeding is not recommended during therapy. |
| Lactation Rating | L5 (Contraindicated) |
| 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 | 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. |
■ FDA Black Box Warning
None
| Serious Effects |
History of depressionActive peptic ulcerUlcerative colitisElectroconvulsive therapy (ECT)Concomitant use with MAOIs
| 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 |
| Food/Dietary | Avoid tyramine-rich foods (aged cheese, cured meats, fermented products, soy sauce, yeast extracts) as reserpine can potentiate pressor responses, leading to hypertensive crisis. Alcohol may increase sedative effects. Grapefruit juice may alter drug metabolism; limit intake. |
| Clinical Pearls | Serpasil (reserpine) is an antihypertensive and antipsychotic that depletes catecholamines from peripheral sympathetic nerve endings and CNS. Onset is slow (3-6 days) and effects persist for weeks after discontinuation. Monitor for depression, especially in patients with history. Avoid in patients requiring MAOIs due to hypertensive crisis risk. Use with caution in peptic ulcer disease due to increased gastric acid secretion. Bradycardia and nasal congestion are common side effects. |
| Patient Advice | Take exactly as prescribed; do not stop suddenly as blood pressure may rise rapidly. · Report any symptoms of depression, mood changes, or suicidal thoughts immediately. · Avoid alcohol and over-the-counter cold or allergy medications containing decongestants. · May cause drowsiness or dizziness; avoid driving until you know how the drug affects you. · Contact your healthcare provider if you experience slow heartbeat, fainting, or severe stomach pain. |
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