Zalcitabine (Hivid, ddC)

What Is ddC?

ddC (Hivid®) was a drug used for antiretroviral therapy (ART). It was manufactured by Roche. ddC was also known as zalcitabine or dideoxycytidine. ddC was a nucleoside analog reverse transcriptase inhibitor, or nuke.

ddC was approved in 1992 as an antiretroviral drug (ARV) for people with HIV infection. The manufacture and distribution of ddC (Hivid) was discontinued by the manufacturer as of February 15, 2006.

There are no absolute rules about when to start ART. You and your health care provider should consider your CD4 cell count, your viral load, any symptoms you are having, and your attitude about taking HIV medications. Fact Sheet 404 has more information about guidelines for the use of ART.

If you take ddC with other ARVs, you can reduce your viral load to extremely low levels, and increase your CD4 cell counts. This should mean staying healthier longer.

What About Drug Resistance?

Many new copies of HIV are mutations. They are slightly different from the original virus. Some mutations can keep multiplying even when you are taking an ARV. When this happens, the drug will stop working. This is called "developing resistance" to the drug. See Fact Sheet 126 for more information on resistance.

Sometimes, if your virus develops resistance to one drug, it will also have resistance to other ARVs. This is called "cross-resistance."

Resistance can develop quickly. It is very important to take ARVs according to instructions, on schedule, and not to skip or reduce doses.

How Is ddC Taken?

ddC is available in film-coated tablets of 0.75 mg or 0.375 mg. The normal adult dose is one 0.75 mg tablet three times a day.

Be sure your health care provider knows if you have had liver or kidney problems. Your liver and kidney will have to be watched carefully if you take ddC, and your health care provider might decide that you should not use ddC at all.

What Are the Side Effects?

When you start any ART you may have temporary side effects such as headaches, high blood pressure, or a general sense of feeling ill. These side effects usually get better or disappear over time.

The most common side effects of ddC are rashes, chest pain, fever, nausea, changes in liver function, and mouth sores.

The most serious side effects of ddC are peripheral neuropathy and, in rare cases, pancreatitis.

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 ddC, or reduce the dose. If you continue to take ddC after nerve damage shows up, it may become permanent. See Fact Sheet 555 for more information.

Pancreatitis is an inflammation of the pancreas, a large gland located behind the stomach. Pancreatitis can be fatal. If you are taking ddC and have sharp pain near your stomach, back, or sides, with nausea and vomiting, you should stop taking ddC immediately and call your health care provider.

How Does ddC React With Other Drugs?

ddC can interact with other drugs or supplements you are taking. These interactions can change the amount of each drug in your bloodstream and cause an under- or overdose. New interactions are constantly being identified. Make sure that your health care provider knows about ALL drugs and supplements you are taking.

ddC is more effective if taken with other ARVs.

ddC should not be combined with 3TC (lamivudine, Epivir®), d4T (stavudine, Zerit®), or ddI (didanosine, Videx®).

Blood levels of ddC may be decreased by antacids or cimetidine.

Blood levels of ddC may be increased by aminoglycosides, amphotericin B, foscarnet, or probenecid.

Several other medications can make the side effects of ddC worse.-->