Antiviral Flashcards
Nucleoside analogues
Acyclovir Famciclovir Valacyclovir Panciclovir Ganciclovir Valganciclovir Cidofovir Trifluridine
Nucleoside analogues - MoA
Prodrugs that are converted to monophosphate by virus enzymes, and then to active triphosphate metabolites by host enzymes. Competitive inhibition of viral DNA polymerase.
Acyclovir - Clinical use
HSV, VZV
Prophylaxis of CMV
Chickenpox
IV form: most effective treatment for serious herpesvirus infections, including herpetic encephalitis and severe HSV and VZV infections in immunocompromised patients
Topical form: herpes genitalis and mild mucocutaneous infections in immunocompromised patients. In cases of herpes genitalis, however, topical form is less effective than oral form
Acyclovir - Adverse effects
Well tolerated
Headache, GI disturbances, rash (General for all the nucleoside analoges)
IV: phlebitis + reversible renal dysfunction
Famciclovir - Clinical use
HSV
VZV
Valacyclovir - Clinical use
HSV, VZV
Prophylaxis of CMV , such as in bone marrow and organ transplant recipients and in persons with HIV
Panciclovir - Clinical use
Herpes labialis
Ganciclovir - Clincal use
Prevent CMV diseases, including retinitis, esophagitis, and colitis
HSV: keratitis (infection of the corneal epithelium) caused by HSV-1 and HSV-2
Ganciclovir - Adverse effects
Leukopeina, thrombocytopenia
Retinal detachment, liver and renal dysfunction
Ganciclovir - Interactions
Severe myelosupression with zidovudine
Valganciclovir - Clinical use
Prevent and treatment of less severe CMV infections, including those occurring in renal and heart transplant patients
Cidofovir - Clinical use
Prevent CMV diseases resistant to ganciclovir
Cidofovir - Contraindications
Contraindicated in patients taking other nephrotoxic drugs, such as aminoglycosides and amphotericin B.
Cidofovir - Adverse effects
Nephrotoxicity, neutropenia, metabolic acidosis.
Trifluridine - Clinical use
Ocular herpervirus infections, primarily herpetic epithelial keratitis and keratoconjuctivitis
Pyrophosphate derivative (HSV drug)
Foscarnet
Foscarnet - MoA
Blocks pyrophosphate-binding sites on viral DNA polymerase and prevents attachment of nucleotide precursor to DNA. Does not need activation by viral/host kinases.
Foscarnet - Clinical use
CMV, VZV, HSV
CMV retinitis in AIDS patients
Acyclovir-resistant HSV infections
Shingles
Combined with ganciclovir to treat infections resistant to either drug alone because of their synergistic effect on viral DNA polymerase
Foscarnet - Adverse effects
Renal impairment and acute renal failure, hematologic deficiencies, cardiac arrhythmias + heart failure, seizures, pancreatitis
Renal toxicity can be minimized by administering intravenous fluids to induce diuresis before and during treatment
Nucleoside reverse transcriptase inhibitors (NRTIs)
Didanosine Lamivudine Stavudine Emtricitabine Zidovudine (ZDV) Abacivir (ABC) Tenofovir
Nucleoside reverse transcriptase inhibitors (NRTIs) - MoA
Triphosphate metabolites of the drug compete with nucleoside triphosphates for incorporation into viral DNA. Cause DNA chain termination.
Inhibit host cell DNA polymerase somewhat.
Nucleoside reverse transcriptase inhibitors (NRTIs) - Clinical use
HIV
Some are active for Epstein-Barr virus and hepatitis B virus
Nucleoside reverse transcriptase inhibitors (NRTIs) - Special considerations
Included in almost all HIV treatment regimens.
Often more effective with multiple NRTIs (antimetabolites of different bases of DNA).
Cross BBB.
Careful with renal impairment
Nucleoside reverse transcriptase inhibitors (NRTIs) - Adverse effects
Lactic acidosis, hepatic steatosis, lipodystrophy
First line HIV drugs
Abacivir (ABC)
Tenofovir
Emtricitabine
Lamivudine
Alternative for 1st line drugs for HIV
Stavudine
Didanosine
Nucleoside reverse transcriptase inhibitors (NRTIs) - For treatment of hepatitis B
Lamivudine
Tenofovir
Which NRTI is used to treat HIV in pregnant women?
Zidovudine (ZDV)
Which NRTIs are not used together and why?
Zidovudine and stavudine because they appear to be antagonistic
Abacavir - Adverse effects
Hypersensitivity reactions
Which NRTIs cause Pancreatitis and Peripheral neuropathy
Didanosine and Stavudine
Tenofovir - Adverse effect (the most important)
Renal impairment
Zidovudine - Adverse effect (the most important)
Bone marrow suppression