Pinaverium bromide is a calcium channel blocker with high selectivity for the gastrointestinal tract. It acts as a spasmolytic agent, specifically targeting colonic smooth muscle. It is a quaternary ammonium compound with antimuscarinic properties, but its primary action is via L-type calcium channel blockade in intestinal smooth muscle cells. It is poorly absorbed systemically, making it a gut-selective agent with minimal systemic side effects.
Adult: 50 mg three times a day, preferably before meals. May be reduced to 50 mg twice daily for maintenance.
Note: Swallow the tablet whole with a glass of water, preferably 20 minutes before meals. Do not crush or chew. Can be taken with or without food, but taking before meals may improve symptom control related to eating.
Pinaverium bromide is a calcium antagonist that acts by selectively blocking the influx of extracellular calcium ions through voltage-dependent L-type calcium channels in the smooth muscle cells of the colon. This inhibition prevents the intracellular calcium rise necessary for smooth muscle contraction, leading to muscle relaxation. It also exhibits mild antimuscarinic activity at post-ganglionic parasympathetic nerve endings.
Pregnancy: Category C: Animal studies have shown embryotoxic effects. No adequate and well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus.
Driving: May cause dizziness or blurred vision. Patients should be cautioned about driving or operating machinery until they know how the drug affects them.
| Ketoconazole, Itraconazole, Clarithromycin (CYP3A4 inhibitors) | May increase pinaverium plasma concentrations, potentially increasing side effects. | Moderate |
| Rifampicin, Carbamazepine, Phenytoin (CYP3A4 inducers) | May decrease pinaverium plasma concentrations, reducing efficacy. | Moderate |
| Other anticholinergic drugs (e.g., Atropine, Dicyclomine, Tricyclic antidepressants) | Additive anticholinergic side effects (dry mouth, constipation, urinary retention, blurred vision). | Significant |
| Opioid analgesics (e.g., Morphine, Codeine) | Additive effect on reducing gastrointestinal motility, increasing risk of severe constipation or ileus. | Significant |
| Metoclopramide, Domperidone (prokinetics) | Therapeutic antagonism; pinaverium may counteract the prokinetic effect. | Moderate |
Same composition (Pinaverium bromide (50mg)), different brands: