June, 2010 – The Pharmacovigilance Program at the BC Centre for Excellence in HIV/AIDS has received four reports of suspected drug interaction between ritonavir and triamcinolone acetonide intra-articular injection leading to symptoms of corticosteroid excess (Cushingoid features) and adrenal suppression. The affected patients were HIV-infected adults whose antiretroviral therapy included a protease inhibitor boosted with ritonavir 100-200 mg daily. All patients received one or more injections of triamcinolone acetonide 40-80 mg into shoulder or knee joints. Adrenal suppression (morning serum cortisol <28 nmol/L, reference range 175-685 nmol/L) was diagnosed four to 14 weeks after the first triamcinolone acetonide injection.