Children on phenobarbital monotherapy requires more sedatives during MRI: Phenobarbital monotherapy requires more sedatives

Summary Background: Phenobarbital induces specific hepatic cytochrome P-450 enzyme pathways causing increased clearance of hepatically metabolized drugs. In this study we investigated the duration and additional anesthetic requirement during MRI in epileptic children with or without phenobarbital monotherapy. Methods: ASA I-II, 128 children, aged 1-10 years was included. Group I: epileptic children without anti-epileptic therapy and Group II: children with phenobarbital monotherapy. The initial sedative drugs were 0.1 mgkg-1 midazolam + 2 mgkg-1 ketamine. Additional 1 mgkg-1 ketamine was repeated if required. 0.5 mgkg-1 rescue propofol was provided and repeated to maintain sedation. The duration and consumption of additional sedative requirements was recorded. Results: The duration of initial and two consequent additional sedative requirement were shorter in Group II (p=0.0001, p=0.001 and p=0.27, respectively). Additional ketamine doses required for adequate sedation were lower in Group I (p=0.016). Conclusion: We suggest that the variability in response to the initial sedative agents during MRI required titration of additive sedation with ketamine in epileptic children on phenobarbital monotherapy.