A potential interaction between zidovudine and paracetamol was reported in a 43-year old HIV-infected male who had chronic use of paracetamol (500 mg every 4 hours) prior to starting zidovudine therapy. Paracetamol and zidovudine pharmacokinetics were determined on several occasions and show extremely rapid absorption of both drugs (10-15 min for paracetamol, 15-20 min for zidovudine) with relatively high Cmax values. The patient was treated with one third of the standard zidovudine dose for that time (100 mg four times daily) and no toxicity or opportunistic infections developed of the next 8 months of follow up.
Pharmacokinetics of zidovudine and acetaminophen in a patient on chronic acetaminophen therapy. Burger DM, et al. Ann Pharmacother, 1994, 28: 327-330.

Coadministration of zidovudine (1000-1200 mg/day) and paracetamol (500 mg every 6 h) was studied in 6 HIV-infected subjects and did not result in a significant change in any pharmacokinetic parameter of zidovudine or zidovudine glucuronide. Paracetamol pharmacokinetics were comparable to historical values.
Short-term, combined use of paracetamol and zidovudine does not alter the pharmacokinetics of either drug. Burger DM, et al. Neth J Med, 1994, 44: 161-165.

The effect of various doses of paracetamol (325 mg for 3 days, n=13; 650 mg for 3 days, n=8; 650 mg for 7 days, n=6) on the clearance of zidovudine (200 mg every 4 hours) was studied in HIV-infected subjects. Clearance of zidovudine increased by 5%, 11% and 33% with the three doses studied, resulting in lower serum concentrations of zidovudine.
Acetaminophen does not impair clearance of zidovudine. Sattler FR, et al. Ann Intern Med, 1991, 114: 937-940.

Serum zidovudine and zidovudine glucuronide concentrations were determined in HIV-infected subjects taking regular doses of zidovudine with and without paracetamol. In all patients, concentrations of zidovudine and the glucuronidated metabolite were similar with and without paracetamol.
The effect of acetaminophen on zidovudine metabolism in HIV-infected patients. Steffe EM, et al. J Acquir Immune Defic Syndr, 1990, 3: 691-694.