Barbiturates are contraindicated in clients with regarded barbiturate sensitivity. Barbiturates also are contraindicated in clients with a background of manifest or latent porphyria. WARNINGSpentobarbital raises toxicity of ifosfamide by influencing hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inducers may well boost the