Avarin (Alverine Citrate + Simethicone)
Primary Indication
Avarin is indicated for the treatment of irritable bowel syndrome (IBS), specifically for relief of abdominal pain, discomfort, and bloating. The combination has demonstrated significant efficacy in reducing IBS symptoms compared to placebo 1.
Recommended Dosage
The standard dosing is alverine citrate 60 mg with simethicone 300 mg taken three times daily 1, 2. This can be used either as:
- Continuous therapy: Three times daily for 4 weeks
- On-demand therapy: Taken as needed when symptoms occur (shown to be more effective than usual treatments in improving quality of life) 2
The on-demand approach is particularly practical given IBS symptoms are often intermittent, and this strategy has demonstrated superior outcomes in quality of life improvement (13.8 vs 8.4 points; p<0.0008) and symptom severity reduction compared to standard continuous treatments 2.
Contraindications
Based on the FDA labeling provided 3:
- Known or suspected hypersensitivity to any ingredients
- Kidney disease (absolute contraindication)
Adverse Effects
The safety profile is favorable with adverse events similar to placebo 1, 4. In the pivotal randomized controlled trial of 409 patients, reported adverse events were comparable between the alverine citrate/simethicone group and placebo group 1.
Clinical Efficacy Evidence
The combination demonstrates robust efficacy across multiple outcomes:
- Abdominal pain/discomfort: Significantly lower VAS scores at 4 weeks (40 mm vs 50 mm; p=0.047) 1
- Response rate: 46.8% vs 34.3% with placebo (OR=1.3; p=0.01) 1
- Global symptom improvement: Significantly greater than placebo (p=0.0001) 1
- IBS severity score reduction: 170.0 vs 110.7 with usual treatments (p=0.0001) 2
A meta-analysis of antispasmodics showed that the alverine/simethicone combination produced significant values in global improvement, with the addition of simethicone enhancing the properties of the antispasmodic agent 5.
Guideline Context
The 2021 British Society of Gastroenterology guidelines 6 recommend antispasmodics as first-line pharmacological treatment for IBS. The guidelines note that antispasmodics (including smooth muscle relaxants like alverine) showed efficacy with fewer patients having persistent global symptoms or abdominal pain (RR 0.65; 95% CI 0.56 to 0.76) compared to placebo. Alverine is specifically classified as a direct-acting intestinal smooth muscle relaxant that ameliorates symptoms based on reducing gastrointestinal spasm and dysmotility 6.
Clinical Pearls
- The combination works through dual mechanisms: alverine provides smooth muscle relaxation while simethicone reduces gas-related bloating
- On-demand dosing may be preferable for patients with intermittent symptoms and offers cost advantages
- The medication can be used alongside dietary modifications (first-line soluble fiber, second-line low FODMAP diet) as recommended in guidelines 6
- Titrating dose carefully may improve tolerability, though adverse events are generally minimal
Important Caveat
Screen for kidney disease before prescribing as this is an absolute contraindication 3. The drug should not be confused with topical formulations that may share similar naming conventions 3.