Delavirdine (Rescriptor)

Delavirdine is a non-nucleoside reverse transcriptase inhibitor (NNRTI). The enzyme reverse transcriptase converts single-stranded viral RNA into DNA. Drugs in the non-nucleoside reverse transcriptase inhibitor class stop HIV from replicating within cells by binding near the active site of reverse transcriptase and inhibiting polymerase activity.

Delavirdine was developed by Pharmacia & Upjohn, but marketing rights to delavirdine were sold to Agouron (now part of Pfizer) in late 1999. Delavirdine is marketed under the trade name Rescriptor.

Delavirdine was licensed in the United States in April 1997. Its European application was rejected because the drug did not offer any benefits over other NNRTIs. It is no longer recommended in the USGuidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents due to issues concerning cross-resistance, drug interactions, and dosing schedule.

Delavirdine (Rescriptor) is able to reduce HIV-1 viral load and increase CD4 cell counts in the majority of people taking the drug in combination with at least two other antiretroviral drugs. It is not active against HIV-2. Anti-HIV drug combinations including delavirdine can suppress viral loads for long follow-up periods, but they often have worse outcomes than other combinations. For example, ACTG 261 found that only 26% of people on delavirdine, AZT (zidovudine, Retrovir) and ddI (didanosine, Videx / VidexEC) achieved viral loads below 200 copies/ml after 12 weeks of treatment.^[1]

The recommended dose of delavirdine (Rescriptor) is 400mg or four 100mg tablets three times a day. The 100mg tablets can be dissolved in water or cola to make them easier to take. It may be possible to dose delavirdine twice a day if its levels are boosted with low-dose ritonavir (Norvir). Although prescribing information supplied with the drug still advises that delavirdine should not be taken with food, a recent study has found no significant difference in the amount of drug absorbed when it is taken with food compared with on an empty stomach.