Many of the listed undesirable effects can be assigned to the anticholinergic properties of Hyoscine-N-Butylbromide (Spasmoson).
Adverse events have been ranked under headings of frequency using the following convention: Very common ≥1/10; Common ≥1/100, <1/10; Uncommon ≥1/1,000, <1/100; Rare ≥1/10,000 ,<1/1,000; Very rare <1/10,000; Not known cannot be estimated from the available data.
Immune system disorders:
Not known*: anaphylactic shock including cases with fatal outcome, anaphylactic reactions, dyspnoea, skin reactions (e.g. urticaria, rash, erythema, pruritus)and other hypersensitivity.
Common: accommodation disorders. Not known*: mydriasis, increased intraocular pressure.
Common: dizziness. Not known*: blood pressure decreased, flushing.
Common: dry mouth, constipation.
Skin and subcutaneous tissue disorders:
Not known*: dyshidrosis.
Renal and urinary disorders:
Not known*: urinary retention.
Injection site pain, particularly after intramuscular use, occurs.
Hyoscine-N-Butylbromide, the active ingredient of Spasmoson, due to its chemical structure as a quaternary ammonium derivate, is not expected to enter the central nervous system. Hyoscine-N-Butylbromide does not readily pass the blood-brain barrier.
However, it cannot totally be ruled out that under certain circumstances psychiatric disorders (e.g. confusion) may also occur after administration of Hyoscine-N-Butylbromide (Spasmoson).
*This adverse reaction has been observed in post-marketing experience. With 95% certainty, the frequency category is not greater than common, but might be lower. A precise frequency estimation is not possible as the adverse drug reaction did not occur in a clinical trial database of 185 patients.