Papaverine
Medicinal Chemistry
Molecular Weight
339.39
Molecular Formula
C20H21NO4
IUPAC Name
1-(3,4-dimethoxybenzyl)-6,7-dimethoxyisoquinoline
Pharmacognosy
Biological Source
Papaver somniferum
Active Constituents
Papaverine
Pharmacology & Synthesis
Mechanism of Action
Phosphodiesterase (PDE) inhibitor; increases intracellular cAMP/cGMP, causing smooth muscle relaxation.
Pharmacokinetics (ADME)
A: Rapid but incomplete oral absorption.
D: Highly protein bound.
M: Hepatic.
E: Renal.
Pharmacodynamics
Directly relaxes smooth muscle, especially in blood vessels (vasodilation) and GI tract.
Synthesis Pathway
Derived from tyrosine via reticuline.
Safety, Warnings & Interactions
Adverse Effects
Tachycardia, flushing, headache, hepatic hypersensitivity.
Contraindications
Complete AV heart block.
Drug Interactions
Levodopa (decreases efficacy).
Pharmaceutics & Compendia
Dosage Forms
Injection, ER Capsules
Official Compendia
IP, BP, USP