The most serious side effects of d4T are peripheral neuropathy and lactic acidosis. Peripheral neuropathy is a form of nerve damage. It usually shows up as tingling, numbness, or a sharp burning sensation in the feet, legs, or hands. The nerve damage is usually temporary and will go away if you stop taking d4T, or reduce the dose. If you continue to take d4T after nerve damage shows up, it may become permanent.
Lactic acidosis is a buildup of lactic acid in the blood.
This is a by-product of abnormal energy production by the cells. It may be caused by damage to the mitochondria. See Fact Sheet 554 for more information on mitochondrial toxicity . Lactic acidosis can cause severe damage to the pancreas and liver. Symptoms of lactic acidosis can include weight loss, abdominal pain, and severe fatigue.