Papaverine Hydrochloride

Pronunciation: pap-PAV-uhr-een HIGH-droe-KLOR-ide
Class: Peripheral vasodilator

Trade Names

Pavagen TD
- Capsules, timed-release 150 mg

Pharmacology

Directly relaxes tone of all smooth muscle, especially when spasmodically contracted. Causes vasodilatation of blood vessels of the coronary, cerebral, pulmonary and peripheral arteries; relaxes musculature of bronchi, GI tract, ureters and biliary system.

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Pharmacokinetics

Absorption

Readily absorbed from GI tract. Oral bioavailability is approximately 54%. T _max is 1 to 2 h after a dose.

Distribution

Drug localizes in fat depots and in the liver; remainder is distributed throughout the body. Protein binding is 90%.

Metabolism

Liver.

Elimination

Urine (inactive form). T _{1/ 2} is 0.5 to 2 h. T _{1/ 2} varies widely; constant levels can be maintained by giving drug at 6-h intervals.

Indications and Usage

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

Vascular spasm associated with acute MI (coronary occlusion), angina pectoris, peripheral and pulmonary embolism, peripheral vascular disease in which there is a vasospastic element, certain cerebral angiospastic states, visceral spasm (eg, ureteral, biliary, and GI colic).

Unlabeled Uses

Intracavernous injection for impotence.

Contraindications

Complete atrioventricular (AV) heart block; intracorporeal injection for impotence.

Dosage and Administration

PO 100 to 300 mg 3 to 5 times daily (immediate-release tablets) or 150 mg every 8 to 12 h or 300 mg every 12 h (sustained-release capsules).

IV / IM Initial dose is 30 mg. Repeat doses are 30 to 120 mg every 3 h as needed.

IV 2.5 to 60 mg as intracavernous injection (usually combined with phentolamine mesylate).

General Advice

Do not crush or allow patient to chew sustained-release capsules.

Storage/Stability

Store at room temperature.

Drug Interactions

Effects may be additive.

May reduce effectiveness of levodopa.

Incompatibility

Lactated Ringer's solution incompatible with parenteral formulation; do not mix.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Cardiovascular

Increase in heart rate; slight increase in BP.

CNS

Depression; dizziness; vertigo; headache; drowsiness; sedation; lassitude; malaise; lethargy.

Dermatologic

Flushing of face; sweating; pruritus.

GI

Constipation; nausea; diarrhea; abdominal distress; dry mouth; anorexia.

Hematologic

Eosinophilia.

Hepatic

Jaundice; hepatitis.

Respiratory

Increased depth of respiration.

Precautions

Pregnancy

Category C .

Lactation

Unknown.

Children

Safety and efficacy not established.

Glaucoma

Use drug with caution.

Hepatic hypersensitivity

Hepatic hypersensitivity reported.

Overdosage

Symptoms

Drowsiness, weakness, diplopia, lassitude, depression, nystagmus, incoordination, coma, cyanosis, respiratory depression, anxiety, ataxia, headache, pruritic skin rashes, nausea, CNS depression, blurred vision, GI upset, vomiting, diaphoresis, sinus tachycardia, metabolic acidosis, hyperventilation, hyperglycemia, hypokalemia.

Patient Information

• Instruct patient to take medication at evenly spaced intervals throughout day.
• Advise patient with glaucoma to undergo regular eye examinations.
• Instruct patient to report the following symptoms to health care provider: flushing, sweating, headache, tiredness, jaundice, skin rash, nausea, anorexia, abdominal distress, constipation, or diarrhea.
• Advise patient to avoid smoking and intake of alcoholic beverages or other CNS depressants.
• Caution patient to avoid sudden position changes to prevent orthostatic hypotension.
• Advise patient that drug may cause dizziness, vertigo, and drowsiness, and to use caution while driving or performing other tasks requiring mental alertness.

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