Serpalan, Sk-Reserpine
Classifications: cardiovascular agent; rauwolfia alkaloid; antihypertensive
Pregnancy Category: D


0.1 mg, 0.25 mg tablets


Principal alkaloid of Rauwolfia serpentina. Interferes with binding of serotonin at receptor sites, decreases synthesis of norepinephrine by depleting dopamine (its precursor), and competitively inhibits their reuptake in storage granules. Depletes norepinephrine and serotonin in CNS, peripheral nervous system, heart, and other organs and tissues.

Therapeutic Effects

Sympathetic inhibition seen in small but persistent decrease in BP, frequently associated with bradycardia, and reduced cardiac output. Central effect results in tranquilization and sedation similar to that produced by chlorpromazine.


Mild essential hypertension and as adjunctive therapy with other antihypertensive agents in the more severe forms of hypertension. Also used in agitated psychotic states, primarily in patients intolerant to phenothiazine or patients who also require antihypertensive medication.

Unlabeled Uses

Reduce vasospastic attacks in Raynaud's phenomenon and other peripheral vascular disorders, and for short-term symptomatic treatment of thyrotoxicosis.


Hypersensitivity to rauwolfia alkaloids; history of mental depression; acute peptic ulcer, ulcerative colitis; patients receiving electroconvulsive therapy; within 7–14 d of MAO inhibitor therapy. Safe use during pregnancy (category D) or lactation is not established.

Cautious Use

Renal insufficiency; cardiac arrhythmias; cardiac damage; cerebrovascular accident; epilepsy; bronchitis, asthma; older adults, debilitated patients; gallstones; obesity; chronic sinusitis; parkinsonism; pheochromocytoma.

Route & Dosage

Adult: PO 0.5 mg/d initially, reduced to 0.1–0.25 mg/d
Geriatric: PO Start with 0.05 mg q.d., increase by 0.05 mg per wk



Adverse Effects (1%)

CNS: Drowsiness, sedation, lethargy, mental depression, nervousness, anxiety, nightmares, increased dreaming, headache, dizziness, increased appetite, dull sensorium; prolonged use of large doses: CNS stimulation (parkinsonian syndrome): tremors, muscle rigidity; respiratory depression, convulsions, hypothermia. CV: Bradycardia, edema, orthostatic hypotension, increased AV conduction time (prolonged therapy); angina-like symptoms, arrhythmias, CHF (rare). Special Senses: Nasal congestion, epistaxis, lacrimation, blurred vision; miosis, ptosis, conjunctival congestion (acute toxicity). GI: Dry mouth or excessive salivation, nausea, vomiting, abdominal cramps, diarrhea, reactivation of peptic ulcer (hypersecretion), heartburn, biliary colic. Hematologic: Thrombocytopenic purpura, anemia, prolonged BT. Body as a Whole: Hypersensitivity (Pruritus, rash, asthma), Muscle aches, dysuria, fixed-drug eruptions. Urogenital: Menstrual irregularities, breast engorgement, galactorrhea, gynecomastia, feminization (males), impaired sexual function, impotence.

Diagnostic Test Interference

Possibility of elevated blood glucose values; however, it is also reported that reserpine may decrease thiazide-induced hyperglycemia. Increase in serum prolactin with chronic administration of rauwolfia alkaloids; overdoses may cause initial increase in excretion of urinary catecholamines; decreases with chronic administration. Large doses may cause initial rise in urinary 5 HIAA excretion. Initial IM doses may increase urinary VMA excretion followed by decrease by end of third day of therapy (with oral or parenteral administration). Possible interference with urinary steroid colorimetric determinations: 17-OHCS and 17-KS.


Drug: Diuretics, other hypotensive agents compound hypotensive effects; cardiac glycosides (digoxin) may increase risk of arrhythmias; mao inhibitors may cause excitation and hypertension; cns depressants compound depression; may decrease response to levodopa. Herbal: St. John's wort may antagonize hypotensive effects.


Peak: 2 h. Distribution: Widely distributed, especially to adipose tissue; crosses blood–brain barrier and placenta; distributed in breast milk. Metabolism: Extensively metabolized to inactive compounds. Elimination: Slowly excreted, 60% in feces within 96 h and 10% in urine. Half-Life: 4.5 and 11.3 h.

Nursing Implications

Assessment & Drug Effects

Patient & Family Education

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug