Like any other medicinal product, onabotulinum toxin injections may cause adverse side effects: headaches, migraine, weakness of the muscles of the forehead, itching, rash, etc. If you observe side effects, immediately contact your physician.
In very rare cases excessive weakness of muscles, dyspnoea, difficulty breathing and articulating speech or the signs of allergy: swelling, urticaria, etc. are possible. In this case, immediately notify your physician of the symptoms or contact emergency medical care personnel, if your physician is not available.