14th Annual Conference of the British HIV Association 23–25 April 2008, Belfast

INTERACTIONS BETWEEN IMMUNOSUPPRESSANTS AND ANTIRETROVIRAL THERAPY (ARVT) IN SOLID ORGAN TRANSPLANT RECIPIENTS: A ROLE FOR NON-NUCLEOSIDE REVERSE TRANSCRIPTASE AND PROTEASE INHIBITOR-SPARING REGIMES

HIV Med 2008; 9(Suppl. 1):43 (abstract no. P124)

B Nathan¹, M Tredger¹, S Doshi¹, R Kulasegaram² and CB Taylor^1
1King’s College Hospital NHS Foundation Trust, London, UK, ²Guy’s and St Thomas’ Hospitals NHS Foundation Trust, London, UK

BACKGROUND: Interactions between immunosuppressants, NNRTIs and PIs are common and often unpredictable due to variable interactions with CYP3A4 and P-glycoprotein.

We present three cases of organ recipients who had drug interactions resulting in significant toxicity requiring dose alteration.

Case 1: A 56 year old woman who underwent liver transplantation for hepatitis B susequently acquired HIV. She was on stable ciclosporin based immunosuppression and commenced on saquinavir/ritonavir 1000/100 mg bd containing ARVT. Ciclosporin levels peaked at 1005 mcg/L (normal range <200 mcg/L) requiring the patient to be admitted to hospital for monitoring of renal function. Her ciclosporin dose was reduced to 25 mg every third day.

Case 2: A 37 year old HIV positive man underwent liver transplantation for hepatitis B and was on stable tacrolimus based immunosuppression. Efavirenz was switched to nevirapine resulting in an increase in tacrolimus levels peaking at 22 mcg/mL (normal range 1–12 mcg/L) and worsening renal function.

Case 3: A 40 year old HIV positive man underwent renal transplantation for HIVAN. He was taking fosamprenavir/ritonavir 700/100 mg bd ARVT and commenced on ciclosporin based immunosuppression. Fosamprenavir levels increased to 4000 ng/mL (therapeutic range <400 ng/mL) associated with disabling diarrhoea requiring discontinuation of ritonavir.

CONCLUSION: In patients with NRTI options agents such as raltegravir and enfurvitide may be useful in the treatment of HIV positive solid organ transplant patients in the peri-transplant period because of their minimal interactions with cytochrome P450 and P-glycoprotein.

2008-04-23
P124

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