Zidovudine absorption and small intestinal function in HIV seropositive patients.

Zidovudine absorption was evaluated in HIV seropositive patients with (n = 15) and without diarrhoea (n = 20) in a standardised prospective pharmacokinetic study using single oral 200 mg doses. Zidovudine was rapidly absorbed with large peak variation (Cmax: 1.10 +/- 0.43 mg/L). There were no significant associations between pharmacokinetic parameters and presence of diarrhoea, CD4 counts, red blood cell folate concentrations, stool cultures/leucocytes or the lactulose/mannitol absorption test. Mean diarrhoea AUC (mg/L.h) was 1.13 +/- 0.30 and 1.07 +/- 0.36 in non-diarrhoeal patients. Antidiarrhoeals increased AUC and Cmax values in a small, non statistically significant subset of diarrhoea patients. Although zidovudine absorption varies significantly, our data do not support dosage individualisation based on any of the above parameters.