Severe toxic reaction to tinidazole

A physician aged 44 years participated as a volunteer in pharmacokinetic studies with tinidazole (FASIGYN, Pfizer). He received 1600 mg of the drug as an intravenous infusion over 80 min. Shortly afterwards, he fainted and was unconscious for about 10 s. The attack was followed by low blood pressure, nausea and tiredness for several h. The serum concentration of tinidazole was 35.4 mg/l when the attack started. Blood tests showed a normal immunoglobulin E level, and a transient fall in the concentration of complement factor C3 after the infusion. It is concluded that tinidazole caused an acute toxic reaction with subsequent activation of complement factors.