How Do CMV Antivirals Work?

Cytomegalovirus (CMV) or human CMV antiviral drugs are used for the treatment and prevention of CMV infections. CMV is a common virus in the same family as herpesvirus, and it can infect anyone. CMV spreads by direct contact with body fluids, such as saliva, blood, urine, semen, vaginal fluids, congenital infection, and breast milk.

Primary infection with CMV is common and may be asymptomatic. When first infected, some adults may have symptoms similar to infectious mononucleosis, including:

• Fever
• Fatigue
• Sore throat
• Muscle aches

Most of the CMV antivirals work by inhibiting the enzyme DNA polymerase that is essential for the catalysis of DNA synthesis for viral replication. There are several antiviral drugs with each having a different approach to inhibiting DNA polymerase.

• The active metabolite of cidofovir inhibits the viral replication by selectively inhibiting DNA polymerase and this leads to inhibition of viral DNA synthesis.
• Foscarnet selectively inhibits the pyrophosphate binding site on viral DNA polymerase.
• Ganciclovir triphosphate and valganciclovir are competitive inhibitors of the incorporation of deoxyguanosine triphosphate into DNA and inhibit viral DNA polymerases. Ganciclovir triphosphate also disrupts viral DNA synthesis by interfering with chain elongation.

Letermovir, a CMV antiviral drug, is a viral terminase inhibitor, and it specifically inhibits the CMV viral terminase complex which is encoded by the CMV genes UL56, UL51, and UL89. This inhibition prevents the cleavage of DNA Concatemers, resulting in long uncleaved DNA and noninfectious viral particles.

CMV antivirals are used to treat and prevent CMV infection.

Side effects associated with CMV antivirals include:

• Nausea and vomiting
• Abdominal pain
• Fever and chills
• Dyspepsia
• Diarrhea
• Anorexia
• Elevated liver enzymes
• Headache
• Alopecia (hair loss)
• Skin rash
• Itching
• Insomnia (trouble sleeping)
• Difficulty breathing
• Gastritis (inflammation of the stomach)
• Nephrotoxicity (functional impairment of the kidneys due to the toxic nature of the drug)
• Electrolyte disturbances
• Hematological disorders
• Uveitis (inflammation of uvea in the eye)
• Iritis (inflammation of the iris)
• Retinal detachment
• Decreased intraocular pressure
• Genital ulcers
• Neurological disorders
• Phlebitis at the site of injection (inflammation of the vein)

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of CMV antivirals include:

• Cidofovir (Vistide)
• Foscarnet (Foscavir, Phosphonoformic acid)
• Ganciclovir (Cytovene)
• Letermovir (Prevymis)
• Valganciclovir (Valcyte)