[Drug interaction between ceftriaxone and theodrenaline/cafedrine : A case example].

Adverse interactions between intravenous medications which are given simultaneously are a common problem in intensive care medicine. They are usually caused by administering a high number of medications over a limited number of intravenous lines or central venous catheters; however, this issue also arises in routine anesthetic procedures during surgery. The following case report highlights a so far undocumented interaction between the combination of theodrenaline/cafedrine and various antibiotics.Laparoscopic cholecystectomy was performed in a female patient, classified as ASA 1. After induction of general anesthesia 2 g ceftriaxone were administered as a perioperative antibiotic prophylaxis. Simultaneously, i.e. prior to the beginning of surgery, a mild decrease in blood pressure was observed and 2 ml diluted Akrinor® (2 ml theodrenaline/cafedrine + 8 ml NaCl 0.9%) was administered. Directly following this administration a chemical precipitation reaction occurred, and large white pasty flakes were noticed in the intravenous line. The infusion was stopped immediately and all lines were replaced.In order to confirm a causal relationship between the observed precipitation and the simultaneous administration of the two drugs, an in vitro test was performed by mixing Akrinor® with other preparations of cephalosporin antibiotics. The effect observed with ceftriaxone was reproducible and cefazoline also caused a precipitation reaction.