Antivirals

Phosphorylated by viral thymidine kinase to acyclovir monophosphate, which blocks viral DNA polymerase → stops viral DNA synthesis

Herpes simplex virus (HSV), varicella- zoster virus (VZV)

Pregnancy category B

SE: IV infusion associated with reversible obstructive nephropathy, rarely may see severe CNS Pregnancy category B changes (i.e., seizures)

Prodrug of acyclovir, same mechanism of action (viral thymidine kinase-dependent activity)

HSV, VZV, cytomegalovirus (CMV)

Category B

Better bioavailability than acyclovir

SE: TTP/HUS^* seen in advanced HIV disease and transplant patients taking high doses

Phosphorylated by viral thymidine kinase (similar mechanism to acyclovir)

HSV, VZV

Low bioavailability so typically used in topical form

Prodrug of penciclovir with same mechanism as above

HSV, VZV

Category B

Better bioavailability than Category B penciclovir

Phosphorylated by viral thymidine kinase; same mechanism as above

CMV (retinitis)

Category C

Better activity against CMV than acyclovir; ↓ oral bioavailability

SE: neutropenia, bone marrow suppression, mucositis, thrombocytopenia, seizures hepatic dysfunction

Noncompetitive inhibition of viral DNA polymerases; analogue of pyrophosphate

Does not require phosphorylation so active against acyclovir-resistant viruses

CMV (retinitis), resistant HSV, resistant VZV

Category C

Only IV form; active against infections resistant to acyclovir, famciclovir, ganciclovir

SE: penile ulcerations or erosions, nephrotoxicity

Nucleoside analogue, inhibits viral DNA polymerase, independent of thymidine kinase activation

CMV

Category C

IV only; active against infections resistant to ganciclovir/foscarnet

SE: renal proteinuria, renal toxicity, ↑ creatinine

Inhibit uncoating of viral DNA within infected host cells (prevents replication)

Influenza A/C, rubella

Category C

SE: anticholinergic symptoms, Category C ataxia, and photosensitivity

Zidovudine (AZT)

Thymidine analogue, inhibits HIV reverse transcriptase (RT)

SE: melanonychia, mucocutaneous pigmentation, bone marrow suppression, lipodystrophy

Pregnancy category C

Didanosine (ddI)

Pyrimidine analogue, similar to AZT

SE: pancreatitis, optic neuritis, peripheral neuropathy, lactic acidosis; pregnancy category B

Abacavir (ABC)

Nucleoside RT inhibitor

SE: hypersensitivity reaction
(can be fatal upon rechallenge)

Pregnancy category C

Nucleotide analogue, inhibits RT

Peripheral wasting, cushingoid appearance
Pregnancy category B

Block HIV-1 protease enzymes

SE: lipodystrophy (buffalo hump), gynecomastia, periungual pyogenic granulomas, paronychia, hepatotoxicity