Less Common Side Effects

Three drug side effects, although rare, require immediate medical attention:

Lactic acidosis: damage to mitochondria caused by your antiretroviral medication or toxicity from other medications can cause a build-up of lactic acid in the body.

Pancreatitis:  mitochondrial damage or drug toxicity can cause painful inflammation of the pancreas 

Abacavir hypersensitivity: abacavir can cause an allergic-like reaction called a hypersensitivity reaction.

These side effects are severe and can be fatal.

Lactic acidosis 

Lactic acid is produced by the body’s cells as they use energy to function. Minor increases in lactic acid are fairly common after exercise but are usually temporary. But when lactic acid reaches a higher level, there is a risk of a serious condition called lactic acidosis.

Lactic acidosis was once relatively common but thanks to much safer HIV treatments in use today, it is extremely rare.

Although other medications can cause lactic acidosis, most cases have occurred in people using nucleoside analogues (nukes). These include AZT (Retrovir, and in Combivir, Trizivir and generic formulations), and in very rare cases, tenofovir (Viread, and in Truvada, Biktary, Descovy, Genvoya, Atripla, Complera and Stribild). Cases have also been reported with the broad-spectrum antiviral drug ribavirin.

Researchers think these drugs can damage mitochondria (your cells’ energy factories), leading to a dangerous buildup of lactic acid. Lactic acidosis causes non-specific symptoms, including:

• fatigue
• nausea
• vomiting
• abdominal pain
• sudden unexplained weight loss
• shortness of breath or difficulty breathing (respiratory symptoms)
• neurologic symptoms (including difficulty moving)
• changes in blood circulation indicated by cold hands or feet or blue colour in the skin

If you experience these symptoms, tell your healthcare provider.

Because mitochondrial damage is thought to be an underlying cause of lactic acidosis, some people take supplements to try and prevent or reverse mitochondrial damage. It is not clear how effective this approach is in preventing lactic acidosis. These supplements are:

• antioxidants (vitamin C, carotenoids, selenium and others), which can be found in some multivitamin- mineral and/or antioxidant formulas
• B vitamins, found in a B complex formula or a multivitamin that contains the whole B complex
• Co-enzyme Q₁₀
• acetyl-L-carnitine (500 mg, three times daily with meals)

A separate supplement of N-acetyl-cysteine (NAC; 600 mg, three times daily with meals) is sometimes added to boost glutathione levels, since glutathione is an antioxidant that can be deficient in HIV disease.

Pancreatitis

Pancreatitis is an inflammation of the pancreas, the organ that secretes digestive enzymes and insulin. Pancreatitis is rarely linked to HIV treatment today, though it has been associated with 3TC (lamivudine and in Combivir, Kivexa, Delstrigo, Dovato, Trizivir and in generic formulations). However, 3TC-related pancreatitis is extremely rare today.

Protease inhibitors and the non-nucleoside analogue efavirenz (Sustiva, and in Atripla) have also been rarely associated with pancreatitis. In addition, high levels of blood fats can put people living with HIV at increased risk for pancreatitis. Other possible causes are gallstones, alcohol, street drugs and other medications or infections.

Pancreatitis may cause symptoms such as:

• severe nausea
• vomiting
• severe abdominal pain

The risk of pancreatitis may be higher when people drink a lot of alcohol. If sudden and severe abdominal pain is accompanied by nausea and vomiting that lasts several hours, especially after drinking a lot of alcohol, pancreatitis is a possibility. If left untreated, pancreatitis can be fatal. If there is any suspicion of pancreatitis, seek immediate medical attention.

Abacavir hypersensitivity

Without screening, an allergic-like reaction called a hypersensitivity reaction occurs in up to eight percent of people who start taking abacavir (Ziagen, and in Triumeq, Trizivir, Kivexa and generic formulations). A screening test is available that identifies the version of the gene HLA-B*5701 linked to the hypersensitivity reaction. This test can identify most people who are susceptible to this problem, reducing the risk of a reaction to less than one percent. Anyone considering therapy with any abacavir- containing medication should be screened with this test before starting treatment. Now that screening is standard practice, abacavir hypersensitivity reactions are extremely rare.

When an abacavir hypersensitivity reaction does occur, it usually appears during the second week of therapy, although in some people it can take up to six weeks for symptoms to develop. Very rarely, the reaction can develop much later in people who have taken the drug for an extended period with no symptoms.

The most common symptoms of abacavir hypersensitivity are fever and rash, as well as a combination of flu-like symptoms: fatigue, headache, nausea, vomiting, diarrhea, sore throat, cough, shortness of breath, and aches and pains. These symptoms usually get worse over time. In anyone taking abacavir, such symptoms should be reported to a healthcare provider immediately.

If you are experiencing a hypersensitivity reaction, you will be told to stop the drug immediately. Anyone who has had this hypersensitivity reaction cannot take medications that contain abacavir again, since restarting the drug could cause severe illness or death.