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- Human immunodeficiency virus (HIV) facts
- What is the history of HIV, and when was HIV discovered?
- What tests are used in the diagnosis of HIV?
- How is HIV spread (transmitted)?
- What are symptoms and signs of HIV infection and AIDS in men, women, and children?
- What happens after an exposure to the blood or genital secretions of an HIV-infected person?
- What laboratory tests are used to monitor HIV-infected people?
- What are HIV treatments and medications? What are the key principles in managing HIV infection?
- When should antiviral therapy be started?
- What is the initial therapy for HIV?
- What are nucleoside and nucleotide analogue reverse transcriptase inhibitors (NRTIs)?
- What are nonnucleoside analogue reverse transcriptase inhibitors (NNRTIs)?
- What are protease inhibitors?
- What are fusion inhibitors?
- What is a CCR5 antagonist?
- What is an integrase strand transfer inhibitor?
- What HIV drugs are in development?
- What are side effects of HIV therapy?
- What happens if the patient's viral load increases while on HIV therapy?
- What are the risks of missing doses or stopping antiviral therapy?
- Should patients with the flu- or mono-like illness of primary HIV infection be treated?
- What about treatment for HIV during pregnancy?
- What can be done for people who have severe immunosuppression?
- What is the future for HIV-infected individuals with regards to treatment simplification and cure research?
- What is in the future for preventing HIV transmission?
Quick GuideHIV AIDS Pictures Slideshow: Myths and Facts on Symptoms and Treatments
What are protease inhibitors?
PIs block the action of an HIV enzyme called protease that allows HIV to produce infectious copies of itself within HIV-infected human cells. Thus, blocking protease prevents HIV in already-infected cells from producing HIV that can infect other, not yet infected cells.
- saquinavir (Invirase and Fortavase, SQV), which comes as the hard gel capsule Invirase (INV),
- ritonavir (Norvir, RTV),
- indinavir (Crixivan, IDV),
- nelfinavir (Viracept, NFV),
- fosamprenavir (Lexiva, FPV),
- lopinavir/ritonavir (Kaletra, LPV/r),
- atazanavir (Reyataz, ATV),
- tipranavir (Aptivus, TPV),
- darunavir (Prezista, DRV).
Each of these drugs has been shown to effectively reduce the viral load when used in combination with other active drugs.
LPV/r comes coformulated as Kaletra while all other RTV-containing regimens require taking RTV along with the other PI. In the case of TPV, RTV must be given as 200 mg with each dose of TPV twice per day. In contrast, ATV can be given without RTV at a dose of two 200 mg capsules once daily or 300 mg with 100 mg RTV once daily. The latter should always be used in PI-experienced subjects and when used in combination with TDF or NNRTIs which can reduce the drug levels of ATV. Similarly, FPV is also used differently in PI-naïve and experienced individuals. In treatment-naïve individuals, it can be given as two 700 mg tablets twice daily or two 700 mg tablets (1,400 mg total) with either 100 or 200 mg RTV, all once daily. In treatment-experienced patients, or when used with NNRTIs, it should be given as one 700 mg tablet with 100 mg RTV, both twice daily. The most recently approved of the PIs is DRV, which was initially used exclusively in treatment-experienced patients with drug-resistant virus. In this setting, it is given as 600 mg with 100 mg RTV, both given twice daily. More recently, DRV was approved for those who have never been treated before given at a dose of 800 mg once daily with 100 mg of RTV once daily.
|SQV, saquinavir; IDV, indinavir; NFV, nelfinavir; FPV, fosamprenavir; LPV/r, lopinavir plus ritonavir; ATV, atazanavir; TPV, tipranavir; DRV, darunavir.|
1Administered with RTV at a dose of 100 mg twice a day.
2FPV can be given without RTV in patients without resistance to PIs or at a dose of 1,400 mg once daily with either 100 mg or 200 mg of RTV once daily. In treatment-experienced patients, FPV is given at a dose of 700 mg twice daily with RTV 100 mg twice daily.
3ATV can be given alone at a dose of 400 mg once daily or at a dose of 300 mg once daily with RTV 100 mg or COBI 150 mg once/daily.
4TPV is always given at a dose of 500 mg twice/daily with RTV 200 mg twice daily.
5DRV can be given to those with a history of drug resistance at a dose of 600 mg twice daily with 100 mg RTV twice daily. For those without resistance, it can be given at a dose of 800 mg with 100 mg RTV or 150 mg COBI once daily.
|Dose in each pill (mg)||500||400||625||700||200/50||200 or 300||250||400 or 600|
|Schedule||21 twice a day||2 every 8 hours||2 twice a day||2 twice a day or with RTV2||2 twice a day or 4 once a day||2 (200) or 1 (300) with RTV or COBI3 once a day||24 twice a day||8005 once a day with RTV or COBI given once per day or 600 twice a day with RTV given with each dose5|
|Meal restrictions||With large meals||1 hour before or 2 hours after meals, or with low-fat meals||With meals||None||With meals||With meals||With meals||With meals|
Although RTV is approved for treatment of HIV-infected patients at a dose of 600 mg twice daily, it is virtually never used at this dose because of severe side effects. Because of this, it is not included in the above table. However, PIs are frequently dosed with low doses of RTV. RTV delays the clearance of the other drugs from the system, making them easier to take and more effective. The dose of RTV varies depending upon which drugs it is being taken with and how it is being administered. The only PI that is not substantially affected by RTV is NFV. Another recently approved boosting agent is COBI which has no anti-HIV activity but can be given with once daily ATV or DRV as an alternative to RTV for pharmacologic boosting. There are also fixed-dose combinations of each, for example, ATV 300 mg combined with COBI 150 mg and DRV 800 mg combined with COBI 150 mg.