2 - Antivirals/Fungal/Parasite, TB Flashcards
TB
- type of agent
- # 1 symptom
- active vs latent tx
RNA pol
Night sweats
Active = combo = (RIPE) Latent = isoniazid or rifampin monotherapy (think chest x-ray)
Rifampin
- MOA
- adverse effects
Prevents mRNA synthesis (transcription) by binding to the beta subunit of DNA-dependent RNA pol
Hepatotoxicity (= incr AST and ALT) is most common
Orange-pink urine and tears (*unique)
Exudative conj-itis is rarely reported
Isoniazid
- MOA
- adverse effects
Prevents cell wall synth by inhibitbing mycolic acid synth
Hepatotoxicity
Pyridoxine (vit B6) deficiency -> peripheral neuropathy
Optic neuritis: rare (also optic atrophy, both leading to vision loss)
Ethambutol
- MOA
- adverse effects
Inhibits synth of mycobacterial cell wall by inhibiting arabinosyl transferase
OPTIC NEURITIS: RETROBULBAR, BILATERAL (pt sees nothing, dr sees nothing; 25yo with 20/200 OU)
- complaints of reduced VA, color blindness
- vision loss is usually reversible, may take months to normalize
- pts should rec’v baseline and periodic assessment of VA and RG color discrimination
Oseltamivir
- MOA
- clinical indications
- adverse effects
Inhibits flu A and B viral neuramidase
Prevents spread of virus along mucous lining of resp tract
Influenza therapy
Conj-itis in 1% of pts
Zidovudine
- MOA
- clinical indications
- adverse effects
Nucleoside analog of thymidine - potent inhibitor of viral RNA-dependent DNA pol (reverse transcriptase)
Major component of 3-drug therapy for HIV (recall AIDS at <200 CD4)
During pregnancy to lower risk of transmission to fetus
Bone marrow suppression
Lactic acidosis
Muscle breakdown: myopathy, myositis
Amblyopia + macular edema have been reported: unknown why
Ribavirin
- MOA
- clinical indications
- adverse effects
Inhibits viral RNA pol
Always used in combo with interferon
Hep C (recall A+B have vaccines, vowels are fecal-oral transmission)
Conj-itis is most common ocular SE RIVAViriN*: -RD -Ischemia (CWS) -Bleeding (heme) -A/V occlusions -optic Neuritis *with long-term (9-12mo), not huge deal/usually goes away, VA okay
Herpes
- type of microbe
- MOA for ALL anti-herpetic drugs
- examples of varients
DNA virus
Inhibit DNA pol
Simplex, zoster, cytomegalovirus
Trifluridine
- MOA
- clinical indications
- adverse effects
Inhibits DNA pol
Herpes simplex keratitis (dendrites)
-bad dosing (9x/day)
Thimerisol preservative
Acyclovir, Valacyclovir, Famciclovir
- MOA
- clinical indications
- adverse effects
Inhibit DNA pol - systemic
Anti-herpetic:
- cold sores (HSV1)
- genital sores (HSV2)
- shingles (HZV)
- HZO
- HSV keratitis, incl prophylaxis for recurrent
HA + GI are most common, esp in pts with renal dysfunction
Elderly/immunocompromised + pts with renal/liver dz should be dosed and monitored carefully
HSV epithelial keratitis standard of care
Oral antivirals (acyclo/valacyclo/famciclo/ganciclovir, trifluridine)
Ganciclovir
- MOA
- clinical indications
- vs Viroptic
- adverse effects
Inhibits DNA pol
HSV keratitis
Intraocular sustained-release capsule for CMV retinitis
Better dosing (5x/day) Reduced corneal toxicity (BAK preserved, not thimerosal)
Topical: blur, irritation
IV: immediate but temporary decr VA, RD, vitreous hemorrhage
Foscarnet
- MOA
- clinical indications
- adverse effects
DNA pol inhibitor - administered as IV
Safety net if ganciclovir fails for CMV ret
Acyclovir-resistant HSV infections in pts with AIDS (CD4 < 200)
Nephrotoxicity
Seizures
Anti-fungals
- target for most drugs
- drugs that punch holes
- drugs that inhibit synth
- drug that inhibits mitosis, interferes with microtubules
Ergosterol: component of fungal cell walls not found in human cells (analogous to cholesterol)
NatamyCIN, amphoteriCIN B, nystaTIN
KetoCONAZOLE, fluCONAZOLE, miCONAZOLE
Griseolfulvin
Natamycin, Amphotericin B, Nystatin
- MOA
- clinical indications
Bind to ergosterol, forms pores
Nata: FDA approved - fungal bleph, conj-itis, keratitis; Candida, Aspergillus, Fusarium
AmphoB: broad-spec topical for fungal keratitis, IV for systemic/intraocular fungal infections
- topical only thru compounding pharmacy
- nephrotoxicity common with IV tx
Nyst: not indicated for ophthalmic use
-Candida oral (thrush), vaginal (yeast) infxns