OBJECT DRUGS

• Theophylline

PRECIPITANT DRUGS

Enzyme Inducers:

• Barbiturates
• Bosentan (Tracleer)
• Carbamazepine (Tegretol, etc.)
• Dabrafenib (Tafinlar)
• Dexamethasone (Decadron, etc.)
• Efavirenz (Sustiva)
• Griseofulvin
• Lumacaftor (Orkambi)
• Nevirapine (Viramune, etc.)
• Oxcarbazepine (Trileptal, etc.)
• Phenytoin (Dilantin, etc.)
• Primidone (Mysoline)
• Rifabutin (Mycobutin)
• Rifampin (Rifadin, etc.)
• Rifapentine (Priftin)
• St. John's wort

Comment:

Enzyme inducers enhance the metabolism of theophylline by CYP3A4 and probably also CYP1A2, thus reducing theophylline serum concentrations. Higher than usual theophylline doses may be needed in the presence of an enzyme inducer. Accordingly, serious theophylline toxicity has been reported following discontinuation of an enzyme inducer in patients stabilized on theophylline.

Class 3: Assess Risk & Take Action if Necessary

• Monitor: Monitor for altered theophylline serum concentrations if an enzyme inducer is initiated, discontinued, or changed in dosage.