Table 4: Potential ARV Interactions

Inhaled Corticosteroids

Fluticasone:

• PIs: caution: ↑ serum fluticasone levels; can cause systemic corticosteroid side effects, including Cushing syndrome
  • Avoid (or limit) use with RTV, particularly in the LPV/r, ATV/r, and DRV/r combinations
  • Even boosting dosages of RTV (eg, 100 mg BID) may ↑ serum fluticasone C_max by 2,500%
  • ATV: can ↑ fluticasone levels - use with caution
  • It is unclear whether significant interactions occur between other inhaled steroids and PIs
• NRTIs, NNRTIs: no significant interactions expected

Long-Acting Beta Agonists

• CYP 3A4 inhibitors such as RTV may ↑ salmeterol levels

Theophylline

• RTV: ↓ theophylline AUC
• IDV: small ↑ in theophylline AUC
• Monitor and adjust theophylline dosing as needed

Leukotriene receptor antagonists

• Zafirlukast may inhibit CYP 3A4 and 2C9, potentially interacting with PIs (no formal studies); monitor clinically for adverse effects. Montelukast has not been shown to inhibit CYP 3A4.