Drotaverine Side Effects
Drotaverine is generally well-tolerated with predominantly mild, transient side effects including transitory hypotension, vertigo, nausea, and vomiting, with no serious adverse events reported in clinical trials.
Common Side Effects
The most frequently reported side effects of drotaverine are mild and self-limiting 1:
- Transitory decrease in blood pressure - the most common cardiovascular effect 1
- Vertigo (dizziness) - frequently reported but typically resolves without intervention 1
- Nausea or vomiting - gastrointestinal effects that are generally mild 1
Clinical Trial Safety Data
In a randomized, double-blind, placebo-controlled study of 102 patients with renal colic, drotaverine demonstrated a favorable safety profile 1:
- No serious adverse effects occurred in any patient receiving drotaverine 1
- 20 minor side effects were reported in the drotaverine group compared to 4 in placebo 1
- None of the patients required treatment for side effects 1
In a separate multicentric study of 180 IBS patients, drotaverine was well tolerated without any major side effects over 4 weeks of treatment 2.
Mechanism-Related Considerations
Drotaverine acts as both a PDE4 inhibitor and L-type voltage-operated calcium channel blocker 3. Despite these mechanisms:
- No clinically significant cardiovascular events have been documented in therapeutic use 1
- The drug does not modify neural-mediated inhibitory responses in the colon 4
- At therapeutic concentrations (80 mg doses), drotaverine does not cause smooth muscle dysfunction 4
Important Clinical Caveats
While laboratory studies have shown cytostatic effects at concentrations as low as 3.0 μM in cancer cell lines 5, these findings are from in vitro studies and have not translated to clinical concerns at standard therapeutic doses of 80 mg three times daily 2.
The transitory hypotension warrants monitoring in patients with baseline low blood pressure or those on antihypertensive medications, though no specific contraindications have been established in clinical guidelines 1.