Papaverine (Latin papaver, "poppy") is an opium alkaloid antispasmodic drug, used primarily in the treatment of visceral spasms and vasospasms (especially those involving the intestines, heart, or brain), occasionally in the treatment of erectile dysfunct + some more technical info. Chemically it is a benzylisoquinoline derivative with the accepted name 1-(3,4-dimethoxybenzyl)-6,7-dimethoxyisoquinoline, CAS 58-74-2, molecular formula C20H21NO4 and molecular weight 353.39 g mol-1. It is a weakly basic, lipophilic molecule with limited water solubility and good solubility in organic solvents and ethanol. Pharmacologically papaverine acts primarily as a nonselective phosphodiesterase inhibitor, raising intracellular cyclic AMP and cyclic GMP in smooth muscle cells and producing direct smooth muscle relaxation and vasodilation; at higher concentrations additional effects such as inhibition of calcium influx and interference with mitochondrial oxidative phosphorylation may occur. Clinically it is administered orally, intravenously, intramuscularly or by local injection depending on indication and formulation; it undergoes extensive hepatic metabolism by O-demethylation and conjugation with renal excretion of metabolites, and the plasma half-life in adults is typically on the order of one to a few hours.
Parent: Papaverine
Parent: Papaverine
Parent: Papaverine
Parent: Papaverine
Parent: Papaverine
Parent: Papaverine
Parent: Papaverine
Parent: Papaverine Hydrochloride / Papaverine
Parent: Papaverine
The manufactured active substance and finished formulations are controlled for specific related compounds and general impurities using validated chromatographic methods such as HPLC and LC MS. Typical related substances include O-demethylated derivatives (norpapaverine and other demethylated benzylisoquinolines), papaverine N-oxide, oxidative degradation products and synthetic by products from upstream alkylation steps. In standard quality control practice each identified related compound is limited to low single digit parts per thousand by weight, commonly specified as less than 0.1 to 0.5 percent w w for individual specified impurities and total impurities controlled below about 1.0 percent w w, with unspecified impurities held to tighter reporting thresholds; residual solvents and heavy metals are controlled to ICH and pharmacopeial limits. Stability testing targets prevention of oxidative and hydrolytic degradation and uses appropriate packaging and antioxidant measures when required.
Papaverine is used to relieve smooth muscle spasms of visceral organs, to treat or reverse vasospasm including cerebral and coronary vasospasm in selected clinical settings, and as a component of intracavernosal therapy for erectile dysfunction in specific cases; it is also used intraoperatively to reduce vasospasm during vascular procedures.
Papaverine primarily inhibits phosphodiesterase enzymes nonselectively, increasing intracellular cyclic AMP and cyclic GMP in smooth muscle cells which leads to relaxation; at higher concentrations it can inhibit calcium entry and affect mitochondrial respiration, contributing to its vasodilatory and spasmolytic effects.
Papaverine is chemically named 1-(3,4-dimethoxybenzyl)-6,7-dimethoxyisoquinoline and is commonly provided as papaverine hydrochloride in pharmaceutical preparations.
Papaverine is used when smooth muscle spasm or vasospasm is the primary therapeutic target and when alternative safer agents are unsuitable; its use and route should be determined by a clinician based on the indication, patient comorbidities and monitoring capability.
