Papaverine
Papaverine (Pavabid)
Papaverine
(pah- PAV-er-een)
Pregnancy Category: C Pavabid Plateau Caps Pavagen TD (Rx)

Classification: Peripheral vasodilator

Action/Kinetics: Direct spasmolytic effect on smooth muscle, possibly by inhibiting cyclic nucleotide phosphodiesterase, thus increasing levels of cyclic AMP. This effect is seen in the vascular system, bronchial muscle, and in the GI, biliary, and urinary tracts. Large doses produce CNS sedation and sleepiness. May also directly relax cerebral vessels as it increases cerebral blood flow and decreases cerebral vascular resistance. Depresses cardiac conduction and irritability and prolongs the myocardial refractory period. Localized in fat tissues and liver. Steady plasma concentration maintained when drug is given q 6 hr. Peak plasma levels: 1-2 hr. t 1/2: 30-120 min. Sustained-release products may be poorly and erratically absorbed. Metabolized in the liver and inactive metabolites excreted in the urine.

Uses: Relief of cerebral and peripheral ischemia associated with arterial spasm and myocardial ischemia complicated by arrhythmias.

Contraindications: Complete AV block.

Special Concerns: Safe use during lactation or for children not established. Use with extreme caution in coronary insufficiency and glaucoma.

Side Effects: CV: Flushing of face, hypertension, increase in HR and depth of respiration. Large doses can depress AV and intraventricular conduction, causing serious arrhythmias. GI: Nausea, anorexia, abdominal distress, constipation or diarrhea, dry mouth and throat. CNS: Headache, drowsiness, sedation, vertigo. Miscellaneous: Sweating, malaise, pruritus, skin rashes, chronic hepatitis, hepatic hypersensitivity, jaundice, eosinophilia, altered LFTs.

Laboratory Test Alterations: AST, ALT, and bilirubin.

Overdose Management: NOTE: Both acute and chronic poisoning may result from use of papaverine. Symptoms are extensions of side effects.
Symptoms (Acute Poisoning): Nystagmus, diplopia, drowsiness, weakness, lassitude, incoordination, coma, cyanosis, respiratory depression. Treatment (Acute Poisoning): Delay absorption by giving tap water, milk, or activated charcoal followed by gastric lavage or induction of vomiting and then a cathartic. Maintin BP and take measures to treat respiratory depression and coma. Hemodialysis is effective.
Symptoms (Chronic Poisoning): Ataxia, blurred vision, drowsiness, anxiety, headache, GI upset, depression, urticaria, erythematous macular eruptions, blood dyscrasias, hypotension. Treatment (Chronic Poisoning): Discontinue medication. Monitor and treat blood dyscrasias. Provide symptomatic treatment. Treat hypotension by IV fluids, elevation of legs, and a vasopressor with inotropic effects.

Drug Interactions: Diazoxide IV / Additive hypotension Levodopa / Levodopa effect by blocking dopamine receptors

How Supplied: Capsule, Extended Release: 150 mg; Injection: 30 mg/mL

Dosage
?Capsules, Timed-Release Ischemia.
150 mg q 12 hr. May be increased to 150 mg q 8 hr or 300 mg q 12 hr in difficult cases.