Hyoscine butylbromide is a semi-synthetic, quaternary ammonium derivative of scopolamine. It is a potent antispasmodic and antimuscarinic agent that acts as a competitive antagonist at muscarinic acetylcholine receptors, primarily in the smooth muscle of the gastrointestinal, biliary, and genitourinary tracts. Due to its quaternary structure, it has limited passage across the blood-brain barrier, minimizing central nervous system side effects. It is a first-line treatment for acute abdominal colicky pain in the Indian clinical setting.
Adult: Oral: 10-20 mg, 3-4 times daily. Maximum: 80 mg/day. Parenteral (IV/IM): 10-20 mg, repeated after 30 minutes if necessary. Maximum parenteral dose: 100 mg/day.
Note: Tablets can be taken with or without food. Swallow whole with a glass of water. Do not crush or chew. For acute colic, parenteral administration (IV/IM) provides faster relief. IV injection should be given slowly over at least 1 minute.
Competitively and selectively blocks muscarinic acetylcholine receptors (M1, M2, M3) located on the smooth muscle cells of visceral organs. This blockade inhibits the action of acetylcholine released from parasympathetic nerve endings, preventing the influx of calcium ions and resulting in smooth muscle relaxation. It has a direct spasmolytic effect on smooth muscle, independent of its anticholinergic action.
Pregnancy: Category C (US FDA). Animal studies have shown adverse effects. Use during pregnancy only if the potential benefit justifies the potential risk to the fetus. Avoid in first trimester unless absolutely necessary. Not recommended for use in labor as it may cause fetal tachycardia.
Driving: May cause dizziness, blurred vision, or drowsiness. Patients should be cautioned against driving or operating machinery until their response to the drug is known.
| Other Anticholinergics (e.g., Atropine, Dicyclomine, Tricyclic Antidepressants, Antihistamines) | Additive anticholinergic side effects (dry mouth, constipation, urinary retention, confusion). | Major |
| Metoclopramide, Domperidone | Pharmacological antagonism; hyoscine reduces GI motility, while prokinetics increase it. Reduced efficacy of both. | Moderate |
| Potassium Chloride (wax-matrix tablets) | Increased risk of GI mucosal lesions due to reduced motility and prolonged contact time. | Moderate |
| Digoxin | Increased bioavailability of digoxin due to reduced GI motility, potentially leading to toxicity. | Moderate |
| Levodopa | Reduced absorption of levodopa from the GI tract, potentially decreasing its efficacy. | Moderate |
| Alcohol, CNS Depressants (Benzodiazepines, Opioids) | Enhanced sedative effect. | Moderate |
Same composition (Hyoscine butylbromide (10mg)), different brands: