Symptomerne kan variere fra CNS- depression (sedation, apnø, nedsat mental parathed, cyanose, koma, kadiovaskulært kollaps) til CNS- stimulering (søvnløshed, hallucination, tremor, kramper) med muligt fatalt forløb.
Symptoms may vary from CNS depression (sedation, apnoea, diminished mental alertness, cyanosis, coma, cardiovascular collapse) to CNS stimulation (insomnia, hallucination, tremors, convulsions) with possible fatal outcome.