Risk for gastrointestinal adverse events in the form of nausea, vomiting and diarrhoea motivates vigilance against insufficient intake of food, especially of carbohydrate.

Very common adverse reactions of cidofovir that can be confused with an acute porphyric attack are nausea, vomiting and diarrhoea. These side effects may potentially be porphyrinogenic if leading to a decrease in carbohydrate intake.

Cidofovir is not metabolized via CYP450 enzymes and there are no drug-drug interactions with cidofovir as a perpetrator.

Pyrimidones

Cidofovir is a nucleoside analogue that is active against herpesviruses. It is indicated for the treatment of cytomegalovirus (CMV) retinitis in patients with AIDS. It is administered by intravenous infusion. Terminal plasma half-life is 2-3 hours, while intracellular elimination half-life of metabolites is 24 - 87 hours.

Cidofovir is phosphorylated to its active form by intracellular kinases and is conjugated to choline to form phosphocholine (UpToDate). Cidofovir is eliminated mainly through renal excretion and about 90 % is excreted as unchanged drug in the urine, both by glomerular filtration and tubular secretion (Martindale). Cidofovir is not metabolized by CYP450 enzymes and there are no drug-drug interactions involving CYP450 enzymes described (Lexi-Interact).