Difflam in topical oral preparations is generally well tolerated and side-effects are minor. The following adverse reactions have been reported after use of benzydamine hydrochloride in solution form:
Local Adverse Reactions: The most commonly reported reaction is oral numbness (2.6%). Occasional burning or stinging sensation may occur and has been reported in 1.4% of treated cases. Other local adverse effects were less common and included dryness or thirst (0.2%), tingling (0.2%), warm feeling in mouth and altered sense of taste (<0.1%).
Systemic Adverse Reactions: These were very uncommon and never of a serious nature. They consisted mainly of nausea, vomiting, retching, gastro-intestinal disorders (0.4%), dizziness (0.1%), headache and drowsiness (<0.1%).
Hypersensitivity reactions occur very rarely but may be associated with pruritus, rash, urticaria, photodermatitis and occasionally laryngospasm.