Before using cidofovir, tell your doctor or pharmacist if you are allergic to it; or to other antivirals (such as ganciclovir); or to probenecid; or to other sulfa drugs (such as sulfamethoxazole); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: diabetes, ganciclovir eye implant, kidney disease.

This drug may cause vision changes. Do not drive, use machinery, or do anything that needs clear vision until you are sure you can perform such activities safely. Limit alcoholic beverages.

Older adults may be at a greater risk for kidney damage while using this drug.

During pregnancy, cidofovir should be used only when clearly needed. It may harm an unborn baby. Discuss the risks and benefits with your doctor. The manufacturer recommends avoiding pregnancy. To prevent pregnancy, men with female partners should use effective barrier protections (such as latex or polyurethane condoms) during all sexual activity during treatment and for at least 90 days after stopping the medication. Women should use effective forms of birth control (such as birth control pills and condoms) during treatment and for at least 1 month after stopping the medication.

It is unknown if this medication passes into breast milk. If you have HIV, breast milk may transmit HIV. Consult your doctor before breastfeeding.