Drotaverine is a potent, selective, and direct-acting antispasmodic agent belonging to the isoquinoline class. It is a papaverine derivative but lacks opioid receptor activity. It is widely used in the Indian clinical setting for the treatment of smooth muscle spasm associated with various gastrointestinal, genitourinary, and obstetric/gynecological conditions. Its primary mechanism is the selective inhibition of phosphodiesterase-IV (PDE-IV), leading to increased intracellular cyclic adenosine monophosphate (cAMP) and subsequent smooth muscle relaxation without significant anticholinergic or cardiovascular side effects.
Adult: 40-80 mg (4 to 8 tablets of 10mg) 2-3 times daily. Usual dose is 40 mg (1 tablet of 40mg or 4 tablets of 10mg) three times a day.
Note: Tablets should be swallowed whole with a glass of water, with or without food. Do not crush or chew. For acute colic, a loading dose may be administered as per physician's advice.
Drotaverine exerts its antispasmodic effect through selective and potent inhibition of the enzyme phosphodiesterase type IV (PDE-IV). This inhibition prevents the breakdown of intracellular cyclic adenosine monophosphate (cAMP). The increased cAMP levels activate protein kinase A (PKA), which phosphorylates specific proteins, leading to a decrease in intracellular calcium ion (Ca2+) concentration. Lowered Ca2+ levels inhibit the activity of myosin light-chain kinase (MLCK), resulting in smooth muscle relaxation.
Pregnancy: Category C (as per some references). Animal studies have shown embryotoxic effects at high doses. Adequate and well-controlled studies in pregnant women are lacking. Use during pregnancy, especially the first trimester, only if the potential benefit justifies the potential risk to the fetus. Sometimes used under supervision for cervical spasm during labor.
Driving: May cause dizziness, lightheadedness, or blurred vision. Patients should be cautioned about operating machinery or driving until they are sure they are not affected.
| Levodopa | Drotaverine may reduce the bioavailability and efficacy of levodopa. | Moderate |
| Other Hypotensive Agents (e.g., ACE inhibitors, beta-blockers, nitrates) | Additive hypotensive effect; risk of dizziness and fainting. | Moderate |
| CYP450 Inhibitors (e.g., Cimetidine, Ketoconazole, Erythromycin) | May increase drotaverine plasma levels, increasing risk of side effects. | Moderate |
| CYP450 Inducers (e.g., Rifampicin, Phenobarbital, Carbamazepine) | May decrease drotaverine plasma levels, reducing efficacy. | Moderate |
| Papaverine | Additive pharmacological effect; increased risk of adverse reactions. | Moderate |
Same composition (Drotaverine (10mg)), different brands: