Ritonavir is a common antiretroviral drug prescribed for people afflicted with human immunodificiency virus (HIV). It works by preventing HIV from invading and destroying healthy blood cells. Over time, ritonavir reduces the total amount of HIV produced in the body, making the condition much easier to manage and significantly reducing physical symptoms. Ritonavir is available in oral tablets and liquid form, and comes in generic forms and under the brand name Norvir®.
The drug is classified as a protease inhibitor. Protease is an enzyme that HIV uses to form the proteins necessary to replicate itself. Ritonavir disrupts the activity of protease, preventing viruses from creating effective copies of themselves. With much of the virus halted, the immune system is often able to renew its depleted supply of disease-fighting white blood cells.
HIV is a notoriously difficult condition to treat, and there is no ultimate cure. The virus is capable of replicating very quickly, and few drugs are sufficient at halting its progress over the long term due to its ability to evolve resistances over subsequent generations. Ritonavir is one of the more effective medications available, especially when it is combined with similar protease inhibitors like saquinavir or indinavir. Taking drugs in combination reduces the likelihood of the virus building a resistance.
The most common side effects of ritonavir when it is taken alone or in combination with other drugs are diarrhea, insomnia, fatigue, nausea, and vomiting. Allergic reactions are rare, but patients are carefully monitored for adverse reactions since their immune systems are already severely compromised. It is possible for a person to experience a sudden rise in the level of liver enzymes, a condition that could potentially result in liver damage if it is not detected right away. In addition, some studies suggest that heart functioning can be impaired when taking both ritonavir and saquinavir together. Doctors generally perform extensive blood, heart, and liver tests before prescribing ritonavir to ensure that it will be safe.
A physician will determine dosage amounts based on many factors, including the age of the patient and the amount of other drugs that are to be taken in combination. When the medication is taken alone, the usual dose is 600 mg every 12 hours. Dosage is typically lower when it is taken with another drug to prevent overdose. Tablets are usually taken with meals, and the liquid form can be combined with certain juices or milk to combat the offensive taste.