Ritonavir Boosts the Efficacy of Protease Inhibitors


ritonavirRitonavir is also known by it’s brand name Norvir. Marketed by Abbott Laboratories, Norvir will lose it’s patent on January 28, 2014. The patent for the pediatric exclusivity for ritonavir will also expire on July 28, 2014. With the generic possibilities coming near, researchers are clamoring to commence clinical trials of ritonavir.

As an antiviral medication in the category of protease inhibitors, ritonavir is efficacious at slowing the spread of HIV infection in the body. By preventing CD4 cells that have been infected with HIV from reproducing, ritonavir is particularly effective when combined with other drugs, like nucleoside reverse transcriptase inhibitors (NRTIs).  Initially the side effects of ritonavir were burdensome for patients, and included diarrhea, headache, appetite loss, stomach pain, nausea, exhaustion and weakness. However, with research gleaned from the past decade, ritonavir has proven itself to be effectual in terms of boosting the levels of other protease inhibitors in the bloodstream. The effect of combining ritonavir and NRTIs creates a greater tolerability in patients to the adverse effects of ritonavir. Due to this high potential of gastrointestinal effects many patients with AIDS are taking a reduced dose of ritonavir, while also taking drugs to enhance the bioavailibility and effectiveness of the combination. As a booster drug ritonavir is better tolerated, and providers are stressing this to patients who may be wary of previous experiences with ritonavir, and the severe nausea they may have undergone. Viracept is the only protease inhibitor which cannot be boosted by ritonavir.

The FDA approved dose of ritonavir for adults with HIV infection is 300 milligrams orally, to be taken twice daily, in capsule form. Ritonavir should be taken with food, specifically high-fat foods, such as peanut butter, to reduce stomach side effects. The March 5, 2012 issue of the Journal of Acquired Immune Deficiency Syndromes released a study titled, “Effects of Steady-State Lopinavir/Ritonavir on the Pharmacokinetics of Pitavastatin in Healthy Adult Volunteers”. The study was comprised of doses of 4 milligrams of Pitavastatin, administered once daily on days 1-5 and days 20-24. Lopinavir, 400 milligrams and ritonavir, 100 milligrams, were given to patients twice daily on days 9-24.  The results were reassuring, showing no outstanding safety issues in the co-administration of these drugs. Furthermore, the combination of pitavastatin, lopinavir and ritonavir were tolerated by trial participants well, and they were no noteworthy adverse effects.

LGM Pharma is a provider of the Ritonavir CAS# 155213-67-5 API for research and development purposes, and offers client support throughout the R&D process.

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