Hivid – brand name

ddC – commonly-used name

zalcitabine – generic name

Hivid belongs to a class of HIV drugs called nucleoside reverse transcriptase inhibitors (NRTIs), also known as nucleoside analogs or “nukes.”

Hivid and the other NRTIs block reverse transcriptase, a protein that HIV needs to make more copies of itself. This may slow down HIV disease.

The Food and Drug Administration (FDA) has approved Hivid for use in combination with other HIV drugs for the treatment of HIV infection in adults and adolescents over 13 years of age.

Hivid comes in:

• 0.375 milligram (mg) and 0.75 mg tablets

The usual dose for adults is one 0.75 mg tablet taken three times daily (every eight hours).

Hivid can be taken with or without food, but works better when taken on an empty stomach.

If you have liver, kidney, or pancreas problems, diabetes, or peripheral neuropathy, the dose of Hivid may need to be reduced.

Hivid must be used with other HIV medications to treat HIV.

An experimental liquid formulation of Hivid is available for children through Hoffmann-La Roche (may not be available after 2006).

As with all HIV drugs, it is important to take Hivid as prescribed. Missing or skipping doses can cause your blood levels of the drug to fall too low and resistance can develop. When your virus becomes resistant to an HIV medication, that drug may stop working.

Hivid is sometimes used in salvage regimens for people who can’t use other HIV drugs or for whom other drugs no longer work.

Your doctor can run a resistance test to help determine whether Hivid is likely to work for you.

Hivid isn’t usually used if you are beginning treatment for the first time. This is because it is taken three times per day and has a high rate of side effects. Newer NRTI drugs have replaced Hivid.

The manufacturer of Hivid is planning to discontinue production of the drug in 2006.

If your virus develops resistance to Hivid then it may stop working or not work as well for you. You also may not get as much benefit from the other NRTIs, especially Videx EC (didanosine or ddI).

Sometimes taking more than one medication can cause drug interactions. Taking certain drugs with Hivid can change the amount of Hivid or other drugs in your blood. Your doctor may need to adjust the doses of your drugs to avoid under- or overdosing.

Some drugs should not be taken with Hivid, such as Epivir (lamivudine or 3TC), Zerit (stavudine or d4T), or Videx. You should also avoid using alcohol and antacids (such as Rolaids or Maalox) while taking Hivid.

Several other medications can make the side effects of Hivid worse. Be sure your doctor knows about all the medications you are taking (including over-the-counter, prescription, street drugs, and herbs), even if you only use them occasionally.

For more information and additional resources to check interactions between the particular drugs you are taking, see our info sheet on drug interactions.

Hivid can cause side effects, however most of them are likely to be temporary and go away as your body adjusts to the medication. If you experience any of the side effects listed below, call your doctor for advice. Do not just stop taking your medication.

• Nausea
• Vomiting
• Fever
• Diarrhea or constipation
• Headaches
• Fatigue (unusual tiredness)
• Mouth sores
• Skin rash

More serious side effects:

• Low white blood cell count (neutropenia)
• Peripheral neuropathy (numbness, pain, or tingling, especially in your feet and hands)
• Pancreatitis (inflammation of the pancreas) can be a serious threat to your health. Symptoms include sudden or sharp pains in the middle of the abdomen, fever, nausea, or vomiting.
• An increase of lactic acid in the blood ( lactic acidosis), an enlarged and fatty liver, and liver failure have been reported in people using NRTIs. Lactic acidosis is a rare but potentially fatal side effect. Symptoms include nausea, vomiting, or stomach pain; feeling very weak and tired; shortness of breath.
• Lipodystrophy, which may include elevated blood sugar (glucose), elevated lipid levels ( cholesterol and triglycerides), and fat gain or loss in certain areas. The exact causes of lipodystrophy are not known, but may include HIV and/or HIV drugs. It is unclear if Hivid will cause or impact symptoms of lipodystrophy. For more information on lipodystrophy, see our info sheet.

If you are experiencing persistent, unusual, or serious side effects, call your doctor right away.

Hivid has been studied in both men and women. Its effectiveness and side effects seem very similar in both genders.

Hivid was approved based on ACTG trial 175, which compared Retrovir (zidovudine or AZT) alone, Videx alone, Hivid plus Retrovir, and Videx plus Retrovir. This study included 18 percent, or about 444 women out of 2,467 total participants.

In this trial, the two combination regimens both worked better than Retrovir alone. The Hivid plus Retrovir combination reduced progression to AIDS or death by half compared with Retrovir alone in people who had never before taken AIDS drugs, but showed only a very small benefit in people who had prior experience using Retrovir.

Several later studies showed that Hivid does not seem to work as well as other NRTIs, and today it is not commonly included in combination regimens when new HIV drugs are tested.

In terms of side effects, studies of medical records indicate that women (especially overweight women) taking NRTI drugs, including Hivid, are more likely than men to develop elevated lactic acid levels and enlarged fatty livers.

Studies have shown that pregnant women who use HIV drugs can greatly reduce the risk of passing HIV on to their babies. There have been no formal studies on the use of Hivid during pregnancy. Check with your doctor about the best treatment options for you and your baby if you are thinking of getting pregnant.

Click this link for more information about pregnancy.

People who are starting HIV treatment for the first time may develop Immune Reconstitution Syndrome or IRS (also called Immune Reconstitution Inflammatory Syndrome or IRIS). IRS can happen as a result of the immune system getting stronger and responding to an HIV-related infection such as Mycobacterium avium infection (MAC), cytomegalovirus (CMV), Pneumocystis jirovecii pneumonia (PCP), or tuberculosis (TB). People may have been treated for these infections in the past or not even know they have them. If you notice any unusual symptoms soon after starting HIV drugs for the first time, let your doctor know right away so you can be evaluated and, if necessary, treated.

1		Abrams, D.I, et. al. (1994). A comparative trial of didanosine or zalcitabine after treatment with zidovudine in patients with human immunodeficiency virus infection. New EnglandJournal of Medicine, 330(10). 657-662.
2		Bozzette, S.A, et, al. (1995). Health status and function with zidovudine or zalcitabine as initial therapy for AIDS. Journal of the American Medical Association, 273(4).  295-301.
3		Richman, D.D, et. al. (1994). Resistance to AZT and ddC during long-term combination therapy in patients with advanced infection with human immunodeficiency virus. Journal of Acquired Immune Deficiency Syndromes, 7(2). 135-138.
4		Schooley, R.T, et. al. (1996). Virologic and immunologic benefits of initial combination therapy with zidovudine and zalcitabine or didanosine compared with zidovudine monotherapy. Journal of Infectious Diseases, 173. 1354.