Lopinavir (trade name Kaletra) belongs to the class of anti-HIV drugs called protease inhibitors. Protease inhibitors work by blocking, or inhibiting a part of HIV called protease. When protease is blocked, copies HIV makes of itself are are unable to infect new cells. Kaletra is now approved for prescription. Kaletra is the sixth protease inhibitor to be approved for the treatment of HIV infection.

Taking the drug: The standard dose of Kaletra is three pills taken twice a day with food. Each Kaletra pill contains 133mg of Kaletra and 33mg of the protease inhibitor Norvir (ritonavir). If you're taking Kaletra at the recommended dose, it's important to know that you'll also be taking a total of 200mg of Norvir each day. If you're allergic to Norvir it may not be possible for you to take Kaletra - check with your doctor. Kaletra is also available in a liquid form for children. The Network has a Simple Facts Sheet available on Norvir.

Trial results: Kaletra has shown a strong anti-HIV effect in clinical trials. One study investigated different doses of Kaletra taken with d4T (Zerit) and 3TC (Epivir). No one in this study had taken anti-HIV drugs before. After 72 weeks (nearly a year and a half) of treatment, 80% of the 51 people taking the approved dose of Kaletra had viral load levels less than 400 copies. T-cells increased by an average of 256 cells. About 4% (1 in 25) of the participants dropped out of the study because of side effects.

Another study enrolled people who had previously taken one protease inhibitor in combination with nucleoside reverse transcriptase inhibitors (NRTIs). NRTI anti-HIV drugs are: AZT/trade name Retrovir, ddI/Videx, ddC/HIVID, d4T/Zerit, 3TC/Epivir and abacavir/Ziagen. Study participants took Kaletra in combination with the non-nucleoside reverse transcriptase inhibitor (NNRTI) drug Viramune and two NRTIs. None of the participants had taken NNRTI drugs before. NNRTI anti-HIV drugs are: nevirapine/Viramune, efavirenz/Sustiva, delavirdine/Rescriptor. After 72 weeks of treatment, 75% of the 36 people taking the approved dose of Kaletra have viral load levels of less than 400 copies. T-cells increased by an average of 174 cells. About 9% (1 in 11) of the participants dropped out of this study because of side effects.

One reason a doctor might prescribe Kaletra is because of its strength and because it seems to work for people whose HIV has become resistant to other protease inhibitors. Up until now, when someone has taken a lot of different anti-HIV drugs that have stopped working, it has been complicated to figure out what regimen to take next. Kaletra may be able to work for people whose HIV is resitant to the other approved combinations of anti-HIV drugs. Because of its strength, and including Norvir which some people find difficult to take, the side effects of Kaletra may be stronger as well.

A large, ongoing study is comparing Kaletra taken with d4T and 3TC to the combination of the protease inhibitor Viracept (nelfinavir) taken with d4T and 3TC. The study involves 653 people that have never taken HIV drugs before. After six months of treatment results are similar for both combinations. In the Kaletra/d4T/3TC group, 79% of the participants have viral loads less than 400 copies. In the Viracept/d4T/3TC group, 70% of the participants have viral loads less than 400 copies. T-cell counts in both groups increased by an average of around 150 cells.

Side effects: Kaletra side effects can include diarrhea, significant increases in blood fats (cholesterol and triglycerides), liver toxicity (with increased liver enzymes), stomach pain, feeling weak or tired, headache, nausea and vomiting. Diarrhea was reported by about a quarter of participants in Kaletra studies. Increases in cholesterol and triglycerides were also reported in up to a quarter of study participants. In some cases increases in cholesterol and triglycerides were very large, and regular monitoring of these blood fats is very important for anyone taking Kaletra. People co-infected with hepatitis B and/or C may be at greater risk of developing liver toxicity from Kaletra.

Kaletra may also be linked to a side effect called pancreatitis. Pancreatitis is a potentially dangerous inflammation of an organ called the pancreas. Currently this side effect has been seen in less than 1% (1 out of 100) people taking Kaletra. It is not yet certain if Kaletra causes pancreatitis. All cases have involved people taking other drugs. Researchers are now studying whether Kaletra played a role in the cases of pancreatitis. The manufacturer recommends monitoring triglycerides and amylase in people taking Kaletra to watch for signs of pancreatitis.

Combining Kaletra with other anti-HIV drugs: There are no serious interactions between Kaletra and NRTI anti-HIV drugs. However, it's recommended that the NRTI drug ddI (Videx) be taken one hour before or two hours after Kaletra. The NNRTI anti-HIV drugs efavirenz (Sustiva) and nevirapine (Viramune) lower Kaletra levels in the body. When taking Sustiva or Viramune with Kaletra it is recommended the Kaletra dose be increased to 4 pills twice-daily (total of 8 pills). The NNRTI drug delavirdine (Rescriptor) has not been studied with Kaletra. Based on what is already known about the drugs, it is likely that Rescriptor will increase Kaletra levels.

Drug interactions: The following drugs should NOT be taken with Kaletra: astemizole (trade name Hismanal), cisapride (Propulsid), flecainide (Tambocor), midazolam (Versed), propafenone (Rythmol), pimozide (Orap), terfenadine (Seldane), triazolam (Halcion) and a class of migraine drugs called ergot derivatives. Great care should also be taken about using Viagra. Kaletra is likely to greatly increase levels of Viagra in the body which could lead to serious side effects. Taking the fat-lowering drugs lovastatin (Mevacor) or simvastatin (Zocor) with Kaletra is not recommended. Kaletra may increase the levels of other fat-lowering drugs such as atorvastatin (Lipitor), potentially increasing the chances of side effects. Kaletra increases levels of the antibiotic rifabutin (Mycobutin) making a 75% reduction of the normal rifabutin dose necessary. Kaletra decreases the levels of methadone in the body and methadone doses may need to be increased if these drugs are used together. The herbal supplement St. John's Wort should not be taken as it is likely to significantly decrease Kaletra levels. The TB drug rifampin should be avoided as it also reduces Kaletra levels. Other potential drug interactions are listed in the label that comes with Kaletra which can be downloaded from the Internet at www.Kaletra.com.

The manufacturer of Kaletra has set up a patient assistance program for people having trouble accessing or affording the drug. Call (800) 659-9050 for more information.

The Simple Facts Project is a program of the AIDS Treatment Data Network (The Network). This information does not intend to promote or endorse any specific treatment for any health related condition.