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What is Ritonavir?
Ritonavir is used alone or in combination with other medicines for the treatment of the infection caused by the human immunodeficiency virus (HIV). HIV is the virus that causes acquired immune deficiency syndrome (AIDS).
Ritonavir will not cure HIV infection or prevent AIDS. It helps keep HIV from reproducing and appears to slow down the destruction of the immune system. This may help delay problems that are usually related to AIDS or HIV disease from occurring. Ritonavir will not keep you from spreading HIV to other people. People who receive Ritonavir may continue to have other problems related to AIDS or HIV disease.
Ritonavir is available only with your doctor's prescription.
Ritonavir is indicated in combination with other antiretroviral agents for the treatment of HIV-1 infection.
How should I use Ritonavir?
Use Ritonavir solution as directed by your doctor. Check the label on the medicine for exact dosing instructions.
- An extra patient leaflet is available with Ritonavir solution. Talk to your pharmacist if you have questions about this information.
- Take Ritonavir solution by mouth with food.
- Shake well before each use.
- Use a measuring device marked for medicine dosing. Ask your pharmacist for help if you are unsure of how to measure your dose.
- To improve the taste of Ritonavir solution, you may mix it with 8 ounces of certain liquids (eg, chocolate milk, Ensure, or Advera) as directed in the patient leaflet. If you mix Ritonavir solution with these fluids, be sure to take it within 1 hour of mixing. As your doctor, nurse, or pharmacist if you have any questions about this information.
- Continue to take Ritonavir solution even if you feel well. Do not miss any doses.
- If you miss a dose of Ritonavir solution, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. It is important not to miss doses of Ritonavir solution. Do not take 2 doses at once.
Ask your health care provider any questions you may have about how to use Ritonavir solution.
Uses of Ritonavir in details
Ritonavir is used along with other medication for treating human immunodeficiency virus (HIV 1) infection. It does not completely cure HIV or acquired immunodeficiency syndrome (AIDS).
An HIV protease inhibitor that works by interfering with the reproductive cycle of HIV. [PubChem]
General Dosing and Administration Recommendations
- Ritonavir must be used in combination with other antiretroviral agents.
- Ritonavir Tablets are administered orally. Ritonavir Tablets should be swallowed whole, and not chewed, broken or crushed. Take Ritonavir Tablets with meals.
Recommended Adult Dosage
Recommended Dosage for Treatment of HIV-1:
The recommended dosage of Ritonavir Tablets is 600 mg twice daily by mouth to be taken with meals. Use of a dose titration schedule may help to reduce treatment-emergent adverse events while maintaining appropriate Ritonavir plasma levels. Ritonavir Tablets should be started at no less than 300 mg twice daily and increased at 2 to 3 day intervals by 100 mg twice daily. The maximum dose of 600 mg twice daily should not be exceeded upon completion of the titration.
Recommended Pediatric Dosage
Ritonavir Tablets must be used in combination with other antiretroviral agents. The recommended dosage of Ritonavir Tablets in pediatric patients older than 1 month is 350 to 400 mg per m2 twice daily by mouth to be taken with meals and should not exceed 600 mg twice daily. Ritonavir Tablets should be started at 250 mg per m2 twice daily and increased at 2 to 3 day intervals by 50 mg per m2 twice daily. If patients do not tolerate 400 mg per m2 twice daily due to adverse events, the highest tolerated dose may be used for maintenance therapy in combination with other antiretroviral agents, however, alternative therapy should be considered.
Body surface area (BSA) can be calculated as follows1:
Dose Modification due to Drug Interaction
Dose reduction of Ritonavir is necessary when used with other protease inhibitors: atazanavir, darunavir, fosamprenavir, saquinavir, and tipranavir.
Prescribers should consult the full prescribing information and clinical study information of these protease inhibitors if they are co-administered with a reduced dose of Ritonavir.
Ritonavir has been found to be an inhibitor of cytochrome P450 3A (CYP3A) both in vitro and in vivo (Table 2). Agents that are extensively metabolized by CYP3A and have high first pass metabolism appear to be the most susceptible to large increases in AUC (>3-fold) when co-administered with Ritonavir. Ritonavir also inhibits CYP2D6 to a lesser extent. Co-administration of substrates of CYP2D6 with Ritonavir could result in increases (up to 2-fold) in the AUC of the other agent, possibly requiring a proportional dosage reduction. Ritonavir also appears to induce CYP3A as well as other enzymes, including glucuronosyl transferase, CYP1A2, and possibly CYP2C9.
Drugs that are contraindicated specifically due to the expected magnitude of interaction and potential for serious adverse events are listed both in CONTRAINDICATIONS Table 3 and under Contraindicated Drugs in Table 4.
Those drug interactions that have been established based on drug interaction studies are listed with the pharmacokinetic results in CLINICAL PHARMACOLOGY, Table 2. The clinical recommendations based on the results of these studies are listed in Table 4 Established Drug Interactions: Alteration in Dose or Regimen Recommended Based on Drug Interaction Studies.
A systematic review of over 200 medications prescribed to HIV-infected patients was performed to identify potential drug interactions with Ritonavir. 2 There are a number of agents in which CYP3A or CYP2D6 partially contribute to the metabolism of the agent. In these cases, the magnitude of the interaction and therapeutic consequences cannot be predicted with any certainty.
When co-administering Ritonavir with calcium channel blockers, immunosuppressants, some HMG-CoA reductase inhibitors, some steroids, or other substrates of CYP3A, or most antidepressants, certain antiarrhythmics, and some narcotic analgesics which are partially mediated by CYP2D6 metabolism, it is possible that substantial increases in concentrations of these other agents may occur, possibly requiring a dosage reduction (>50%); examples are listed in Table 4 Predicted Drug Interactions: Use With Caution, Dose Decrease May be Needed.
When co-administering Ritonavir with any agent having a narrow therapeutic margin, such as anticoagulants, anticonvulsants, and antiarrhythmics, special attention is warranted. With some agents, the metabolism may be induced, resulting in decreased concentrations.
| DRUGS THAT ARE CONTRAINDICATED WIT NORVIR USE
Ritonavir side effects
The following adverse reactions are discussed in greater detail in other sections of the labeling.
When co-administering Ritonavir with other protease inhibitors, see the full prescribing information for that protease inhibitor including adverse reactions.
Clinical Trial Experience
Because clinical trials are conducted under widely varying conditions, adverse reactions rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
Adverse Reactions in Adults
The safety of Ritonavir alone and in combination with other antiretroviral agents was studied in 1,755 adult patients. Table 2 lists treatment-emergent Adverse Reactions (with possible or probable relationship to study drug) occurring in greater than or equal to 1% of adult patients receiving Ritonavir in combined Phase II/IV studies.
The most frequently reported adverse drug reactions among patients receiving Ritonavir alone or in combination with other antiretroviral drugs were gastrointestinal (including diarrhea, nausea, vomiting, abdominal pain (upper and lower)), neurological disturbances (including paresthesia and oral paresthesia), rash, and fatigue/asthenia.
Laboratory Abnormalities in Adults
Table 3 shows the percentage of adult patients who developed marked laboratory abnormalities.
Adverse Reactions in Pediatric Patients
Ritonavir has been studied in 265 pediatric patients greater than 1 month to 21 years of age. The adverse event profile observed during pediatric clinical trials was similar to that for adult patients.
Vomiting, diarrhea, and skin rash/allergy were the only drug-related clinical adverse events of moderate to severe intensity observed in greater than or equal to 2% of pediatric patients enrolled in Ritonavir clinical trials.
Laboratory Abnormalities in Pediatric Patients
The following Grade 3-4 laboratory abnormalities occurred in greater than 3% of pediatric patients who received treatment with Ritonavir either alone or in combination with reverse transcriptase inhibitors: neutropenia (9%), hyperamylasemia (7%), thrombocytopenia (5%), anemia (4%), and elevated AST (3%).
The following adverse events (not previously mentioned in the labeling) have been reported during post-marketing use of Ritonavir. Because these reactions are reported voluntarily from a population of unknown size, it is not possible to reliably estimate their frequency or establish a causal relationship to Ritonavir exposure.
Body as a Whole
Dehydration, usually associated with gastrointestinal symptoms, and sometimes resulting in hypotension, syncope, or renal insufficiency has been reported. Syncope, orthostatic hypotension, and renal insufficiency have also been reported without known dehydration.
Co-administration of Ritonavir with ergotamine or dihydroergotamine has been associated with acute ergot toxicity characterized by vasospasm and ischemia of the extremities and other tissues including the central nervous system.
First-degree AV block, second-degree AV block, third-degree AV block, right bundle branch block have been reported.
Cardiac and neurologic events have been reported when Ritonavir has been co-administered with disopyramide, mexiletine, nefazodone, fluoxetine, and beta blockers. The possibility of drug interaction cannot be excluded.
Cushing's syndrome and adrenal suppression have been reported when Ritonavir has been co-administered with fluticasone propionate or budesonide.
There have been postmarketing reports of seizure. Also, see Cardiovascular System.
Skin and subcutaneous tissue disorders
Toxic epidermal necrolysis (TEN) has been reported.
Active ingredient matches for Ritonavir:
ReviewsThe results of a survey conducted on ndrugs.com for Ritonavir are given in detail below. The results of the survey conducted are based on the impressions and views of the website users and consumers taking Ritonavir. We implore you to kindly base your medical condition or therapeutic choices on the result or test conducted by a physician or licensed medical practitioners.
Consumer reported usefulNo survey data has been collected yet
Consumer reported price estimatesNo survey data has been collected yet
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Information checked by Dr. Sachin Kumar, MD Pharmacology