Drugs Flashcards
Zanamivir
Neuraminidase inhibitor - flu A and B Inhalation 15% absorbed and excreted via urine Cough, bronchospasm, decreased lung fxn Approved for children over 7
Oseltamivir
Neuraminidase inhibitor - flu A and B Oral - prodrug with 80% bioavailability Eliminated by kidneys Nausea-vomiting/abdominal pain - less with food Approved for children over 1
Amantadine
Block M2 H+ channel - flu A Resistance via M2 mutation Oral absorption and concentration in lungs CNS penetration Excreted unchanged in urine Insomnia, focus difficulty, headache
Rimantadine
Block M2 H+ channel - flu A
Resistance via M2 mutation
Oral absorption and concentration in lungs
Little CNS distribution - binds to other proteins
Eliminated by liver
Better tolerated than Amantadine
Docosanol
Prevent membrane and lipid envelope fusion
Long chain of saturated alcohols
Topical treatment for HSV given in 12 hours
Abbreva
Acyclovir
Nucleoside analog - phosphorylated in cell by viral kinases. Then inhibits viral DNA polymerase. Can also terminate growing DNA chain.
Resistance with mutated kinase
Plasma half-life shorter than intracellular.
Poor oral absorption - IV, topical, or oral.
Renal excretion
Well tolerated - HA, N/V, renal toxicity with IV route, and some CNS at high dosage.
Higher dose for VZV
Given for CMV induced retinitis.
Valacyclovir
Same as acyclovir, except it is a prodrug
Good oral absorption - 85% bioavailability
Cidofovir
Nucleotide analog - inhibits viral DNA polymerase
IV only with long intracellular half-life
Cleared by tubular secretion - probenecid blocks secretion and lowers nephrotoxicity.
Nephrotoxicity and neutropenia
Foscarnet
DNA polymerase inhibitor
IV only - poor oral absorption and GI intolerance
Renal excretion
Renal impairment, hypocalcemia, HA, and SZ
Ganciclovir
Similar mechanism to acyclovir
IV, intraocular, oral (poor absorption)
Renal elimination
For CMV retinitis in immunocompromised
Myelosuppression, nausea, diarrhea, rash, fever, HA
Valgnciclovir - oral absorbed prodrug form
Amphotericin B (polyene)
Bind ergosterol - open pore - cell death
IV, topical, and oral (poor absorption)
Mostly biliary, some slow renal excretion
Sequestered in liver, spleen, nodes, and lungs
Little to CNS
Nephrotoxicity, anemia/bone marrow depression, and chills/fever/vomiting (with IV use)
Use for systemic/life-threatening fungi (deep candidiasis, aspergilosis, mucormycosis, cryptococcosis, extracutaneous sporotrichosis)
Nystatin
Bind ergosterol - open pore - cell death
Topical only, GI intolerance
Toxicity limits use (more if immunocompromised)
Used for candidial infections
Fluconazole
Triazole: inhibits fungal CYP450 - less ergosterol synthesis, fungistatic.
95% oral bioavailability
Renal excretion and CNS penetration due to lipid solubility
Some inhibition of host CYP450
Well tolerated - GI upset, rash, extra liver enzymes
Use for vaginal candidiasis if other treatments failed, serious systemic candidial infection (oropharyngeal and esophageal), and cryptococcal meningitis in AIDS
Itraconazole
Triazole: inhibits fungal CYP450 - less ergosterol synthesis, fungistatic. Inhibits more than Fluconazole.
95% oral bioavailability
Hepatic metabolism - inhibition of host CYP450
Well tolerated - GI upset, rash, extra liver enzymes
Use - systemic for dermatophytoses and onychomycosis.
Ketoconazole
Imidazole: inhibits P450 dependent 14-alpha-demethylase - less ergosterol synthesis - fungistatic or fungicidal by concentration.
Oral (poor absorption) or IV for systemic
Distributes well to tissue but not CNS
Crosses placenta and excreted in breast milk
Metabolized by CYP450 in liver -DDI and hepatotoxic. Strong inhibitor of CYP3A4.
Anorexia, N/V, rash, dizziness, hepatotoxic and impotence from testosterone reduction.
Use for chronic mucocutaneous candidiasis
