Ritonavir

As Ritonavir is called an HIV protease inhibitor. The drug is used to treat HIV infections such as AIDS.

What is ritonavir?

Ritonavir is an active substance that belongs to the group of protease inhibitors. The drug against HIV infections is administered as a combination preparation. Ritonavir was developed at Abbott Laboratories in the 1990s. The global American pharmaceutical company brought the drug onto the market in 1996 after it had been approved by the Food and Drug Administration (FDA).

Under the product name Kaletra, ritonavir was combined with the protease inhibitor lopinavir. In addition, ritonavir was one of 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 a higher dosage would be required, taking ritonavir can lower the dose and at the same time increase the effect profile.

Ritonavir is a whitish powder that is almost insoluble in water, while the active ingredient can be easily dissolved in methanol and dichloromethane. Furthermore, ritonavir is polymorphic. It is important to protect the drug from light.

Pharmacological effect

Ritonavir belongs to a group of HIV-1 protease inhibitors. The active ingredient is able to inhibit special viral enzymes known as HIV proteases. The HIV proteases break down protein molecules and ensure that the HI virus can pass on its genetic information. Through the joint use of ritonavir and lopinavir, which is also an HIV protease inhibitor, it is possible to prevent the HI viruses from developing further. This leads to the formation of immature viruses, which are less infectious.

The effects of ritonavir and lopinavir are complementary. While lopinavir is targeted against the HI virus, the immunodeficiency virus is attacked by ritonavir in the same places that are also attacked by lopinavir. This displaces lopinavir from these locations so that it can stay longer in the patient's body. In this way, there is a more lasting effect. So the positive effects of lopinavir are enhanced by ritonavir. In addition, the drug ensures that the risk of developing resistance to the drug is reduced.

As ritonavir inhibits the liver enzyme cytochrome P-450 CYP 3A4, it also affects the metabolism of other medicinal products. This makes dosing them more difficult.

Medical application & use

Ritonavir is used to treat HIV infections in adults, adolescents and children aged two years and over. The agent serves to inhibit the multiplication of the HI viruses, which in turn can counteract the onset of AIDS symptoms.

If the patient already has AIDS, ritonavir is administered together with lopinavir to relieve the patient's symptoms and improve their quality of life. Furthermore, the life expectancy of the sick is also improved. Ritonavir is also used in the context of other combination products. It is used to treat the infectious disease hepatitis C.

Ritonavir is administered orally by taking film-coated tablets or syrup.

Risks & side effects

Many side effects are possible with the use of ritonavir, but they do not necessarily occur in every patient. The affected people often suffer from diarrhea, nausea, vomiting, flatulence, abdominal pain, digestive problems, general weakness, taste disorders, headaches, rashes, sweating, sleep disorders, acne and diabetes mellitus.

Blood sugar, blood cholesterol, blood triglyceride and blood amylase levels can also increase. Other possible undesirable side effects are runny nose, inflammation of the paranasal sinuses, Cushing's syndrome, anemia, an underactive thyroid, dehydration, weight gain, immobility, anxiety, movement disorders, dizziness, tremors, thought disorders, gastrointestinal inflammation, nervous disorders Parasitic sensations, nervousness, eczema, itching or joint pain.

Sometimes HIV protease inhibitors like ritonavir cause blood lipid levels to rise. For this reason, the patient must undergo regular medical checks. Increased blood neutral fat levels are also possible through the use of the agent. This in turn can lead to inflammation of the pancreas (pancreatitis). Patients in whom the immune deficiency 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, which is caused by AIDS, further serious illnesses such as CMV retinitis or pneumonia can occur in the initial stage of therapy.

Ritonavir must not be used if the patient is hypersensitive to the drug or if the liver has impaired liver function or severe liver damage. Patients with hepatitis B or C are at risk of fatal side effects and require strict medical monitoring. Since animal studies have shown harm to treatment with ritonavir, the drug should only be administered during pregnancy if no other option is available. The sick mother must avoid breastfeeding the baby.

When taking ritonavir, there is a risk of drug interactions, which in turn can cause side effects. Simultaneous administration of agents such as antihistamines, antidepressants, opioids, neuroleptics, antimycotics, calcium antagonists or steroid hormones are considered unsuitable. You should also refrain from taking the sexual enhancer Sildenafil, as it increases undesirable side effects.

Ritonavir sometimes affects the patient's ability to react so that he or she should not drive or use complicated machines. Allergic reactions are also possible.