Before Using This Medicine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For zalcitabine, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to zalcitabine. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Zalcitabine has not been studied in pregnant women. However, studies in animals have shown that zalcitabine causes birth defects when given in very high doses. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding—It is not known whether zalcitabine passes into the breast milk. However, if your baby does not already have the AIDS virus, there is a chance that you could pass it to your baby by breast-feeding. Talk to your doctor first if you are thinking about breast-feeding your baby.

Children—Zalcitabine can cause serious side effects in any patient. Therefore, it is especially important that you discuss with your child's doctor the good that this medicine may do as well as the risks of using it. Your child must be seen frequently and your child's progress carefully followed by the doctor while the child is taking zalcitabine.

Older adults—Zalcitabine has not been studied specifically in older people. Therefore, it is not known whether it causes different side effects or problems in the elderly than it does in younger adults.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking zalcitabine, it is especially important that your health care professional know if you are taking any of the following:

• Alcohol or
• Asparaginase (e.g., Elspar) or
• Azathioprine (e.g., Imuran) or
• Estrogens (female hormones) or
• Furosemide (e.g., Lasix) or
• Methyldopa (e.g., Aldomet) or
• Pentamidine by injection (e.g., Pentam, Pentacarinat) or
• Sulfonamides (e.g., Bactrim, Septra) or
• Sulindac (e.g., Clinoril) or
• Tetracyclines or
• Thiazide diuretics (water pills) (e.g., Diuril, Hydrodiuril) or
• Valproic acid (e.g., Depakote)—Use of these medicines with zalcitabine may increase the chance of pancreatitis (inflammation of the pancreas)

• Aminoglycosides by injection (amikacin [e.g., Amikin], gentamicin [e.g., Garamycin], kanamycin [e.g., Kantrex], neomycin [e.g., Mycifradin], netilmicin [e.g., Netromycin], streptomycin, tobramycin [e.g., Nebcin]) or
• Amphotericin B (e.g., Fungizone) or
• Foscarnet (e.g., Foscavir)—Use of these medicines with zalcitabine may increase the chance of side effects

• Antacids, aluminum- and/or magnesium-containing (e.g., Maalox, Mylanta)—Use of antacids with zalcitabine may decrease the absorption of zalcitabine; antacids and zalcitabine should not be taken at the same time

• Chloramphenicol (e.g., Chloromycetin) or
• Cisplatin (e.g., Platinol) or
• Dapsone (e.g., Avlosulfon) or
• Didanosine (e.g., Videx, ddI) or
• Disulfiram (e.g., Antabuse) or
• Ethionamide (e.g., Trecator-SC) or
• Glutethimide or
• Gold (arthritis medicine) or
• Hydralazine (e.g., Apresoline) or
• Iodoquinol (e.g., Dinquinol, Yodoxin) or
• Isoniazid (e.g., Nydrazid) or
• Metronidazole (e.g., Flagyl) or
• Phenytoin (e.g., Dilantin) or
• Ribavirin (e.g., Virazole) or
• Stavudine (e.g., Zerit, d4T) or
• Vincristine (e.g., Oncovin)—Use of these medicines with zalcitabine may increase the chance of peripheral neuropathy (tingling, burning, numbness, or pain in your hands or feet)

• Cimetidine (e.g., Tagamet) or
• Probenecid (e.g., Benemid)—Use of these medicines with zalcitabine may increase the chance of side effects of zalcitabine

• Doxorubicin (e.g., Adriamycin or Rubex) or
• Lamivudine (e.g., 3TC, Epivir, Heptovir)—Use of these medicines with zalcitabine may make zalcitabine not work well

• Nitrofurantoin (e.g., Furadantin, Macrodantin)—Use of nitrofurantoin with zalcitabine may increase the chance of side effects, including peripheral neuropathy (tingling, burning, numbness, or pain in your hands or feet) and pancreatitis (inflammation of the pancreas)

Other medical problems—The presence of other medical problems may affect the use of zalcitabine. Make sure you tell your doctor if you have any other medical problems, especially:

• Alcohol abuse or
• Increased amylase (or a history of ) or
• Increased blood triglycerides (or a history of) or
• Pancreatitis (or a history of, or at risk for)
• Receiving nutrition in your veins—Patients with these medical problems may be at increased risk of pancreatitis (inflammation of the pancreas)

• Abnormal liver function, or
• Alcohol abuse, history of, or
• At risk for liver disease, or
• Hepatitis, or
• Liver disease, or
• Obesity, or
• Taking medicines called nucleosides for a long time—Zalcitabine may make liver disease worse in patients with liver disease or a history of alcohol abuse

• Allergy to zalcitabine, or
• Allergy to any part of the medicine—Serious allergic reactions can occur

• Bone marrow disease—Patients with this condition may develop severe blood problems when taking zalcitabine

• Heart problems, or
• Congestive heart failure—Zalcitabine may make these conditions worse.

• Kidney disease—Patients with kidney disease may have an increased chance of side effects

• Low CD4 cell count—Zalcitabine may cause serious side effects in patients with very low CD4 cell counts.

• Peripheral neuropathy or at risk of developing peripheral neuropathy, or
• Diabetes, or
• Low CD4 cell count, or
• Weight loss—Zalcitabine may increase your chance of developing neuropathy or worsening neuropathy.