CYP–450 inducers are:
- P450 inducers

   Phenobarbitone
   Rifampicin
   Phenytoin
   Chloral hydrate
   Griseofulvin
   Phenylbutazone
   DDT
   Chronic alcohol ingestion

-          Cimetidine and Ketoconazole inhibits metabolizing enzymes.
Cimetidine
Ketoconazole
Phenobarbitone
Theophylline