Buscopan Dosing for Muscle Spasm
The standard dose of Buscopan (hyoscine butylbromide) for muscle spasm is 10-20 mg intravenously, which provides adequate spasmolytic effect with minimal side effects. 1
Recommended Dosing Regimen
For smooth muscle spasm, administer 20 mg intravenously as the conventional dose, which has been established as safe and effective in clinical practice. 2 This dosing provides reliable anticholinergic-mediated smooth muscle relaxation through blockade of muscarinic receptors in the gastrointestinal tract. 3
Lower doses of 10 mg IV can be considered when adequate spasmolytic effect is needed with potentially fewer anticholinergic effects, as this has been shown to exert sufficient smooth muscle relaxation. 1
The drug acts locally at the site of action due to its high tissue affinity for muscarinic receptors, despite minimal systemic absorption (bioavailability <1%). 3
Route-Specific Considerations
Intravenous administration is preferred for acute muscle spasm as it provides rapid onset of action, though oral and rectal formulations are available for less acute situations. 3
Oral administration results in very low systemic availability, with plasma concentrations generally below the limit of quantitation, but the drug remains effective due to local action at intestinal muscarinic receptors. 3
Critical Safety Precautions
Before administering Buscopan, you must:
Screen for allergic history to hyoscine compounds. 4
Avoid use in patients with cardiac instability, including those with acute coronary syndrome, uncontrolled heart failure, or recent ventricular arrhythmias. 4
Warn patients about temporary visual accommodation impairment lasting 12-21 minutes post-administration, particularly in patients ≤50 years old, and advise against driving until vision normalizes. 2, 4
Provide specific instructions to seek urgent medical attention if painful or blurred vision develops in one or both eyes, as this may indicate acute angle-closure glaucoma (rare but serious). 4
Expected Effects and Tolerability
Buscopan is generally well tolerated with few adverse events reported, as it does not cross the blood-brain barrier and has minimal systemic absorption. 3 The primary side effect is temporary blurred near vision in approximately 5% of patients, occurring within 12-21 minutes of IV administration and resolving spontaneously. 2
The spasmolytic effect varies by gastrointestinal location, with increasing sensitivity from esophagus to colon, jejunum, and ileum, corresponding to regional differences in muscarinic receptor expression. 5