tebipenem and Seizures

A patient presented with convulsive seizures when sodium valproate (VPA) and tebipenem pivoxil (Orapenem) were co-administered accidentally. The seizures were suspected to be caused by a reduced concentration of VPA in the blood.. A 6-year-old boy (weight: 16 kg, at the start of treatment) began sodium valproate (valproate syrup 5%) treatment for epilepsy in February 2012. At a dose of 350 mg/day, he experienced no convulsive seizures and maintained stable symptoms for the past 9 months. In December, he was prescribed 160 mg/day tebipenem pivoxil by an otolaryngologist for inflammation of the tympanic membrane. He experienced convulsive seizures the day after beginning co-administration. The concentration of VPA in his blood at this time was 30.0 μg/mL, which was lower than the optimal blood concentration.. Marked reduction of VPA concentration in the blood due to co-administration of VPA and injectable carbapenem antibiotics has been well-documented; however, this is the first report of such an interaction with tebipenem, which is an orally-administered carbapenem antibiotic. Although the mechanism of drug interaction between VPA and carbapenem antibiotics is not fully understood, it is thought that VPA blood concentrations decrease due to production of valproic acid glucuronic acid conjugates (VPA-Gluc) being promoted directly or indirectly by carbapenem antibiotics. When we assessed the patient according to the DIPS system, we calculated a score of +4 (possibility of interaction).. The results suggest that co-administration of oral carbapenem antibiotics and VPA should be avoided.

Topics: Anti-Bacterial Agents; Anticonvulsants; Carbapenems; Child; Drug Interactions; Drug Monitoring; Humans; Male; Medication Errors; Polypharmacy; Seizures; Valproic Acid

Tebipenem pivoxil (TBPM-PI), the first oral carbapenem antibiotic both in Japan and abroad, was examined on its convulsive liability. We used ICR male mice and Sprague-Dawley male rats to examine the pro-convulsive effect and anticonvulsive effect of TBPM-PI and its active metabolite, TBPM. (1) When mice were treated with TBPM-PI (30-1000 mg/kg, p.o.) or TBPM (10-300 mg/kg, i.v.), no convulsion was noted at any dose level. When rats were treated with TBPM (300 mg/kg, i.v.), no convulsant effects were noted in electroencephalography or behavioral observation. In intraventricular injection of TBPM in mice, clonic convulsion was observed in 7/10 animals at 100 microg but no effect at 30 microg. On the other hand, the administration of 10/10 microg imipenem/cilastatin (IPM/CS) resulted in clonic convulsion in all animals and tonic convulsion in 3/10 animals, and 4/10 animals died. The administration of 100 microg meropenem did not cause any effects. (2) When mice were co-administered with pentylenetetrazole (45 mg/kg: maximum dose level at which no convulsion is induced) and TBPM-PI (30-300 mg/kg, p.o.) or TBPM (300 mg/kg, i.v.), convulsion enhancing effect was not noted. On the other hand, the co-administration of pentylenetetrazole with IPM/CS (300/300 mg/kg, i.v.) enhanced a convulsive effect of pentylenetetrazole. (3) When mice were treated with TBPM-PI (30-300 mg/kg, p.o.) or TBPM (100 mg/kg, i.v.), inhibitory effect was not noted on convulsions induced by electrostimulation, pentylenetetrazole or strychinine. In conclusion, there were no pro-convulsive effects or anticonvulsive effect in the oral administration of TBPM-PI or intravenous administration of TBPM. Pro-convulsive effect was observed in the intraventricular injection of TBPM as in the case of other carbapenem antibiotics, but such action was weaker than that in IPM/CS administration. Accordingly, the risk of occurrence of convulsion related to TBPM-PI administration was low compared to IPM/CS administration, and TBPM-PI was considered to be less potential to induce convulsions in clinical use.

Topics: Administration, Oral; Animals; Carbapenems; Cilastatin; Cilastatin, Imipenem Drug Combination; Dose-Response Relationship, Drug; Drug Combinations; Drug Synergism; Imipenem; Infusions, Intravenous; Injections, Intraventricular; Male; Mice; Pentylenetetrazole; Rats; Seizures