Major
Rifampicin × Theophylline
Antituberculous antibiotic×Methylxanthine
Mechanism
Rifampicin induces CYP1A2 and CYP3A4. Theophylline falls 50% – bronchoconstriction breakthrough risk.
Symptoms
Return of dyspnoea, bronchospasm.
Management
Double theophylline dose with blood level monitoring.
Check the full regimen, not just this pair
Opens the checker with these two drugs prefilled. Add the rest of the regimen and recompute additive risks.