Ritonavir is the name given to an HIV protease inhibitor. The drug is used to treat HIV infections such as AIDS.
What is ritonavir?
Ritonavir is the name given to an HIV protease inhibitor. The drug is used to treat HIV infections such as AIDS. Ritonavir is an active ingredient that belongs to the protease inhibitors. The drug is administered as a combination preparation against HIV infections. Ritonavir was developed in the 1990s at Abbott Laboratories. The global U.S. pharmaceutical company launched the drug in 1996 following approval by the Food and Drug Administration (FDA). Under the product name Kaletra, ritonavir was combined with the protease inhibitor lopinavir. In addition, ritonavir was among the first antiretroviral agents in this class. A combination between ritonavir and lopinavir is necessary because without ritonavir, lopinavir would be degraded too rapidly. Since this would require a higher dosage, taking ritonavir allows the dose to be lowered while enhancing the efficacy profile. Ritonavir is a whitish powder that is virtually insoluble in water, whereas the active ingredient dissolves readily in methanol and dichloromethane. Furthermore, polymorphism is present in ritonavir. It is important to protect the drug from light.
Pharmacologic Action
Ritonavir belongs to the group of HIV-1 protease inhibitors. Thus, the drug is able to inhibit specific viral enzymes called HIV proteases. The HIV proteases cleave protein molecules and ensure that the HI virus can pass on its genetic information. By using ritonavir and lopinavir together, which is also an HIV protease inhibitor, it is possible to prevent the HI viruses from developing further. This results in the formation of immature viruses whose infectiousness is reduced. The effects of ritonavir and lopinavir are complementary. While lopinavir specifically targets the HI virus, the immunodeficiency virus is attacked by ritonavir at the same sites that are also attacked by lopinavir. This results in the displacement of lopinavir from these sites, allowing it to remain in the patient’s body longer. In this way, there is a more sustained effect. Thus, the positive effect of lopinavir is enhanced by ritonavir. In addition, the drug ensures that the risk of resistance to the drug is reduced. Since ritonavir inhibits the liver enzyme cytochrome P-450 CYP 3A4, it also affects the metabolism of other drugs. As a result, their dosing becomes more difficult.
Medical application and use
For use, ritonavir is used to treat HIV infection in adults, adolescents, and children two years of age and older. In doing so, the drug serves to inhibit the multiplication of the HI viruses, which in turn can counteract the outbreak of AIDS symptoms. If AIDS is already present, ritonavir is administered together with lopinavir to alleviate the patient’s symptoms and improve his or her quality of life. It also improves the life expectancy of patients with the disease. Ritonavir is also used as part of other combination preparations. It is used for the treatment of the infectious disease hepatitis C.
Ritonavir is administered orally by taking film-coated tablets or syrup.
Risks and side effects
Numerous side effects are possible with the use of ritonavir, but not necessarily experienced by every patient. For example, affected individuals often suffer from diarrhea, nausea, vomiting, bloating, abdominal pain, digestive problems, general weakness, taste disorders, headaches, skin rashes, sweating, sleep disorders, acne, and diabetes mellitus. In addition, blood glucose, blood cholesterol, blood triglyceride and blood amylase levels may increase. Other possible adverse side effects include rhinitis, sinusitis, Cushing’s syndrome, anemia, hypothyroidism, dehydration, weight gain, immobility, anxiety, movement disorders, dizziness, tremors, impaired thinking, gastrointestinal inflammation, nervous insensitivity, nervousness, eczema, itching, or joint pain. Sometimes HIV protease inhibitors such as ritonavir cause an increase in blood lipid levels.For this reason, the patient must undergo regular medical checks. Increased blood neutral fat levels are also within the realm of possibility as a result of taking the drug. This in turn can lead to inflammation of the pancreas (pancreatitis). Patients in whom the immunodeficiency disease AIDS is already advanced are considered to be particularly at risk. In the worst case, acute pancreatitis can even lead to death. Due to the weakness of the immune system caused by AIDS, other serious diseases such as CMV retinitis or pneumonia may occur in the initial stage of therapy. Ritonavir should not be used if the patient has hypersensitivity to the drug or suffers from hepatic impairment or severe liver damage. Patients who have hepatitis B or C are at risk of fatal side effects, so they must be under strict medical supervision. Because animal studies have shown harm from treatment with ritonavir, the drug should be administered during pregnancy only if there is no other option. Breastfeeding of the baby must be avoided by the sick mother. By taking ritonavir, there is a risk of interaction with other drugs, which in turn can cause side effects. The simultaneous administration of agents such as antihistamines, antidepressants, opioids, neuroleptics, antifungals, calcium antagonists or steroid hormones is not considered suitable. Likewise, refrain from taking the potency enhancer sildenafil, as it increases undesirable side effects. Sometimes ritonavir affects the patient’s ability to react, so that he should not participate in road traffic or operate complicated machinery. Likewise, allergic reactions are possible.
