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Ritonavir – Effect, Application & Risks


Ritonavir is 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 protease inhibitors. The drug against HIV infections is administered as a combination preparation. Ritonavir was developed at Abbott Laboratories in the 1990s. The globally active American pharmaceutical company brought the drug onto the market in 1996 after approval by the Food and Drug Administration (FDA).

Under the drug 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 of ritonavir and lopinavir is necessary because without ritonavir, lopinavir would be broken down too quickly. Since a higher dosage would be required, the dose can be reduced by taking ritonavir and the effect profile can be increased at the same time.

Ritonavir is an off-white powder that is almost insoluble in water, while the active substance is readily soluble in methanol and dichloromethane. Furthermore, ritonavir is polymorphic. It is important to protect the drug from light.

Pharmacological action

Ritonavir belongs to the group of HIV-1 protease inhibitors. The active substance is able to inhibit special virus enzymes that are called HIV proteases. The HIV proteases split 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 virus from developing further. This leads to the formation of immature viruses, which are less infectious.

The action of ritonavir and lopinavir is complementary. While lopinavir targets the HI virus, ritonavir targets the immunodeficiency virus at the same sites that lopinavir targets. As a result, lopinavir is displaced from these sites, allowing it to stay in the patient’s body longer. This results in a more lasting effect. Thus, the positive effect of lopinavir is enhanced by ritonavir. In addition, the drug ensures that the risk of developing resistance to the drug is reduced.

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

Medical Application & Use

Ritonavir is used to treat HIV infections in adults, adolescents and children from the age of two. The agent serves to inhibit the multiplication of the HI virus, which in turn can counteract the outbreak of AIDS symptoms.

If AIDS is already present, ritonavir is given with lopinavir to relieve the patient’s symptoms and improve their quality of life. In addition, the life expectancy of those affected is also improved. Ritonavir is also used in other combination drugs. It is used to treat the infectious disease hepatitis C.

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

Risks & side effects

Numerous side effects are possible when using ritonavir, but these do not necessarily occur in every patient. The people affected often suffer from diarrhea , nausea , vomiting , flatulence , abdominal pain , digestive problems , general weakness , taste disorders , headaches , skin rashes , sweating , sleep disorders , acne and diabetes ( diabetes mellitus ).

Blood sugar, blood cholesterol, blood triglycerides and blood amylase levels can also increase. Other possible unwanted side effects are a cold , 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 discomfort , 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 possible by taking the drug. This in turn can lead to inflammation of the pancreas ( pancreatitis ). Patients who are already at an advanced stage of the immune deficiency disease AIDS 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 can occur in the early stages of therapy.

Ritonavir should not be used if the patient is hypersensitive to the drug or suffers from liver dysfunction or severe liver damage . Patients with hepatitis B or C are at risk of fatal side effects and need strict medical supervision. Since animal experiments caused damage during treatment with ritonavir, the drug should only be administered during pregnancy if there is no other option. The sick mother must avoid breastfeeding the baby.

By taking ritonavir there is a risk of interactions with other medications, which in turn can cause side effects. The simultaneous administration of agents such as antihistamines , antidepressants , opioids , neuroleptics , antimycotics , calcium antagonists or steroid hormones is not considered suitable. You should also refrain from taking the sexual enhancer Sildenafil , as this increases unwanted side effects.

Sometimes ritonavir affects the patient’s ability to react , so that the patient should not drive or operate complicated machinery. Allergic reactions are also possible.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.