- Nucleoside reverse transcriptase inhibitors (NRTIs). Also called “nucleoside analogs,” these drugs are faulty versions of DNA building blocks. That way, the DNA copy of the virus is defective and isn’t able to replicate or function properly. Examples include Retrovir (zidovudine or azidothymidine, also known as AZT or ZDV), Epivir (lamivudine or 3TC), Viread (tenofovir or TDF), and Videx (didanosine). (AZT was the first HIV drug to be approved, back in 1987.)
- Non-nucleoside reverse transcriptase inhibitors (NNRTIs). These drugs bind to reverse transcriptase and keep the enzyme from turning the RNA into DNA. Examples include Viramune (nevirapine), Sustiva (efavirenz), and Intelence (etravirine), approved in 2008. The first NNRTI was approved in 1996.
- Integrase inhibitors: An HIV enzyme called integrase takes the DNA version of the virus and integrates it into the DNA of the human cell. That way, the HIV virus (now called a “provirus”) can stay inside the cells for a long time and make many copies of itself. Integrase inhibitors keep viral DNA from integrating with your DNA and disrupt the HIV life cycle. An example is Isentress (raltegravir), approved in 2007.
- Protease inhibitors (PIs): Once HIV is part of the cell’s DNA, it can use the cell’s own enzymes to read its DNA and create the proteins that form the envelope or shell for new copies of the virus. These proteins are made in long strings that must be chopped into smaller pieces. A viral enzyme named protease does this job after the new virus buds off the host cell. Protease inhibitors block this step, so that the copies don’t mature into their final form, and aren’t able to infect other cells. Examples include Crixivan (indinavir), Norvir (ritonavir), and Viracept (nelfinavir). (The first PI was approved in 1995.)
- Combination pills: These simply include two or three drugs in fixed amounts, such as Trizivir (contains abacavir or ABC, zidovudine or AZT, and lamivudine or 3TC) and Truvada (contains emtricitabine or FTC and tenofovir or TDF). Combining medicines reduces the number of pills to take and can make it easier to stick to a treatment plan.
What are the possible side effects of HIV medications?
All HIV medications can cause potentially serious side effects, so it’s important that you take your pills exactly as directed every day and talk to your doctor about any complications you experience. Here are some of the possible downsides to HIV treatments:
- Liver damage. NRTIs, NNRTIs, and PIs can all be toxic to the liver. Over time, the liver can become inflamed, and some liver cells can die. The liver may also start accumulating fat, a possible first step toward a dangerous condition called lactic acidosis (see below). Your doctor will run regular blood tests to check for signs of liver damage. Tell your doctor right away if you develop any symptoms of liver trouble including abdominal pain, nausea, vomiting, loss of appetite, diarrhea, fatigue, or jaundice (yellowing of the skin and eyes).
- Lactic acidosis. Patients taking NRTIs are at increased risk for lactic acidosis, an extremely rare but potentially deadly complication caused by a buildup of lactic acid (a waste product of cells) in the bloodstream. Symptoms of lactic acid buildup include fatigue, shortness of breath, rapid breathing, liver swelling or tenderness, poor circulation to the hands or feet, irregular heartbeat, unexplained weight loss, nausea, vomiting, and abdominal pain.
- High blood sugar and diabetes. All PIs can put patients at risk for hyperglycemia (high blood sugar) and diabetes. These complications are especially common in patients who are overweight, older or have a family history of diabetes. If you’re taking a PI, tell your doctor if you have a sign of hyperglycemia, including excessive hunger and thirst, excessive urination, or unexplained weight loss. If you develop hyperglycemia while taking a PI, your doctor may switch you to a different HIV medication or prescribe insulin or another medication to keep your blood sugar under control.
- High cholesterol. A few HIV drugs, including the PI Norvir and the NNRTI Sustiva, can raise blood cholesterol and triglycerides. If your cholesterol or triglycerides get too high, you could be at risk for heart disease. Because of this danger, your doctor will want to check your lipid levels on a regular basis. There are many options for bringing down high cholesterol, including statin drugs such as Lipitor (atorvastatin).
- Lipodystrophy. HIV medications can cause lipodystrophy, a fancy word for problems with fat metabolism or distribution. In some cases, fat can disappear from areas of the body including the face, arms, legs, or buttocks. In other cases, fat may start piling up in places such as the back of the neck, belly, or breasts (in both men and women). Lipodystrophy seems to be most common in people taking both PIs and NRTIs. This condition isn’t especially dangerous, but it can be unsightly. In some cases, people get cosmetic surgery to correct it. It can also be a warning sign of other problems, including high blood sugar, or high cholesterol.
- Weakened bones. Protease inhibitors can rob bones of minerals, potentially making them less dense (a condition called osteopenia). In advanced cases, bones become prone to breaking (a condition called osteoporosis). Some HIV patients also suffer from the death of bone cells (a condition called osteonecrosis), but it’s not clear if this is a drug side effect or a complication of the disease. Your doctor may want you to have regular scans to check bone density, as osteoporosis won’t cause any symptoms until you have a fracture. Fractures can cause pain and tenderness and frequently occur in the spine, wrists, or hips. Calcium supplements, weight-bearing exercises, and medications can help prevent bone loss.
- Skin rash. NNRTIs — and, to a lesser extent, NRTIs and PIs — can cause rashes. The rashes are usually mild, but they can also be severe, especially among patients taking Viramune. Tell your doctor if you develop sores with blisters in the center or if your skin starts peeling leaving behind painful sores.
- Anemia. About 30 percent of HIV patients (and up to 80 percent of those with AIDS) develop anemia, or low red blood cell counts, which results in fatigue. Certain HIV drugs such as AZT can also contribute to anemia. Depending on your red blood cell count, your doctor may prescribe vitamins, drugs to boost red blood cell production, or even transfusions in extreme cases.
How should I take my HIV medications?
That depends. Each medicine will have its own timetable and directions. You’ll need to plan your medication schedule carefully. Some drugs should be taken with a meal, but others work better on an empty stomach. Your doctor or a pharmacist can help you come up with a system that works for you.