acyclovir vs cidofovir
PlainMeds reviewed this comparison against our methodology in August 2026. It places FDA and CMS record fields side by side, without recommending either medication.
Side-by-side comparison of acyclovir and cidofovir. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
minor Known Drug Interaction
Drug Interactions Probenecid Probenecid is known to interact with the metabolism or renal tubular excretion of many drugs (e.g., acetaminophen, acyclovir, angiotensin-converting enzyme inhibitors, aminosalicylic acid, barbiturates, benzodiazepines, bumetanide, clofibrate, methotrexate, famotidine, furosemide, nonsteroidal anti-inflammatory agents, theophylline, and zidovudine).
Acyclovir is an antiviral medicine. It is used to treat infections caused by certain viruses.
Cidofovir injection is an antiviral medicine. It is used to treat CMV retinitis, an eye infection, in people with AIDS.
Acyclovir is used to treat shingles, which is caused by herpes zoster. It also treats genital herpes, both the first time you have it and when it comes back. Acyclovir can also treat chickenpox.
Cidofovir treats CMV retinitis in people who have AIDS. CMV retinitis is an infection in the eye that can cause vision problems. This medicine has not been proven to work for other CMV infections or in people without HIV.
Acyclovir stops the virus from growing and spreading. It does this by interfering with the virus's ability to make copies of itself. This helps your body fight off the infection.
Cidofovir stops the CMV virus from making copies of itself. It does this by blocking a key enzyme the virus needs to reproduce its DNA. This helps to reduce the amount of virus in your body.
- • Malaise (feeling unwell)
- • Nausea
- • Diarrhea
- • Kidney problems
- • Lowered white blood cell count
- • Decreased eye pressure
- • Inflammation inside the eye
- Fatigue 7,612
- Diarrhoea 7,064
- Pneumonia 5,471
- Nausea 5,328
- Pyrexia 4,719
No adverse event reports.
Acyclovir can cause nervous system problems, especially in older adults or people with kidney problems. Tell your doctor if you have kidney problems before taking this medicine.
Cidofovir can cause serious kidney damage, possibly leading to death. To reduce this risk, you must receive IV fluids and take probenecid pills with each dose. Your kidney function and white blood cell counts will be checked regularly. This drug can also cause birth defects and cancer, based on animal studies. It is only for treating CMV retinitis in AIDS patients.
Tell your doctor if you are pregnant or plan to become pregnant. It is not known if acyclovir will harm an unborn baby. Talk to your doctor about the risks and benefits of taking acyclovir while breastfeeding.
Cidofovir may cause harm to an unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is not known if cidofovir passes into breast milk, so talk to your doctor if you are breastfeeding.
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How to Read This acyclovir vs cidofovir Comparison
acyclovir is classified in the Antiviral (Nucleoside Analog) drug class, while cidofovir sits within the Antiviral (Nucleotide Analog) class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, acyclovir has 30,194 submissions while cidofovir has 0. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known minor interaction flagged in FDA labeling, attributed to probenecid is given with cidofovir and can slow down the removal of acyclovir through the kidneys. this can lead to an increase in the amount of acyclovir in your blood.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for acyclovir or cidofovir.
Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.