Antifungals Flashcards
What are the topical drugs for cutaneous fungal inections
Azoles: miconazole, clotrimazole, ketoconazole
Polyene: Nystatin
What are the systemic drugs for superficial fungal infections?
Griseofulvin
Terbinafine
Itraconazole
What are the systemic drugs for systemic fungal infections?
Amphoteracin B
Azoles: ketoconazole, fluconazole, itraconazole, vorconazole, posaconazole
Flucytosine (5-FC)
Topical azoles: miconazole, clotrimazole, ketoconazole CI routes of admin Use with caution in what pateints SE Drug interactions AE
CI
- pregnancy, lacatation
- caution in liver failure
- ketoconazole not for use with history of sulfa allergy
lotion or powder (very little systemic absorption)
-liver failure pts, inhibit CYP450
SE
-puritis, irritation, buring or stinging
Drug interations-
- topical: none
- oral: drug interactions similar to the other azoles due to inhibition of P450 enzymes
AE
- vulvovaginal burning
- abnormal LFTs
- puritius
- n/v
What formulations are available for ketoconazole?
lotion, powder, cream, foam, gel, or shampoo
What formulations are available for Miconazole?
Aerosol, powder aerosol, intravaginal suppository, cream, ointment, lotion
- there is enough systemic absorption with the intravaginal suppositories that it may interfere with warfarin
Topical polyene: Nystatin (mycostatin) CI available formulations Onset of action AE
CI
-hypersensitivity rxn
Formulations
-cream, ointment, powder, oral (swish and swallow), oral (tablets)
-relief of sx within 24-72 hours (no systemic absorption, no drug interactions)
AE
- Contact dermatitis
- Stevens-johnson syndrome
- N/v, diarrhea
Are mycostatin tablets absorbed well?
No, thats why they are good for intestinal infections. The drug stay within the intestines and is able to work. It is not systemically absorbed (which is good because that high of a dose would be toxic).
Griseofluvin is most commonly used to treat what?
Tinea capitis (fungal infection of the scalp)
Griseofluvin
- administration
- CI
- monitoring which systems for long term use
- drug interactions
- adverse rxns
- fatty meal (PB and ice cream) to increase GI absorption
- take with food of milk to decrease GI upset
CI
- liver failure
- porphyria
- Pregnancy cat X
- caution if history of penicillin allergy
- lactation: not recommended
Monitor
-kidney, liver, CBC for granulocytopenia
DI
- warfarin
- oral contraceptives
- alcohol
- barbituates
- cyclosporines
AE
- Photosensitivity, stevens-johnson syndrome,
- jaundice
- granulocytopenia
- dizziness, fatigue, HA
- diarrhea, n/v
- drug induced lupus like syndrome
Griseofluvin: which size particle has better bioavailability?
Ultramicrosize compared to microsize.
better bioavailability because its smaller so you need less (lower dose)
Terbinafine (Lamisil) routes of administration CI metabolism Drug interactions SE
-oral (for fingernails or toenails)
CI
-hypersensitivty
hepatic metabolism, 99% protein bound
DI
-significant interactions due to inhibition of CYP 450 enzymes (metoprolol, tramadol)
SE
- HA
- Diarrhea
- LFTs
-Burning, contact dermatitis, dryness, pruritus, rash
Itraconazole (sporanox) CI absorption metabolism Drug interaction AE
CI
- hypersensitivty
- concurrent administration with other drugs that act on the CYP450 system
- ventricular dysfunction
- CHF
- pregnancy
absorption
- better with food (capsule)
- solution better absorbed on an empty stomach
- requires gastric acidity for optimal absorption
Metabolism
-by liver, 99.8% protein bound
Drug interactions
-Many- pain meds, antiplatelets, anti-hypertensives, cholesterol lowering…
AE
- Nausea, HA, diarrhea
- Rash, edema
- heart failure
- Arrhythmia
- hearing loss
*monitor LFTs
Amphoteracin B used for routes of administration SE Monitoring Drug interactions
Used for SEVERE systemic fungal infections
Routes- IV only
SE
-anaphylaxis, infusion rxn, leukoencephalopathy, nephrotoxicity
Monitoring
-renal and liver function, electrolytes, PT/PTT, CBC
Drug interactions
-aminoglycosides, antifungal agents, corticosteriods, cyclosporines
Fluconazole (Duflucan) CI route distribution drug interactions AE
CI
- hypersensitivity
- coadministration of cyp CYP3A4 which may lead to QT prolongation
Route
-IV and oral
Distribution
-good penetration into CSF, eye, peritoneal fluid, sputum, skin and urine
DI -statins 0viagra -warfarin -sulfonylureas -antihypertensives -diclofenac (NSAID) -fentanyl -macrolide abx
AE
- pregnancy C/D
- HA, dizziness, n/v, diarrhea
- QT prolongation
Systemic Ketoconazole ( Nizoral)
Warning
When to use
SE
- serious hepatotoxicity
- people develop liver failure after taking this when they didnt have any signs of it before.
- risk of decreased adreal corticosteriod secretion
- risk of QT prolongation if on other drugs known to prolong QT
- significant inhibitor of CYP 450 enzymes
- Use only for the treatment of SYSTEMIC life threatening fungal infections when other safer agents cannot be used
- should not be used for candida or dermatophyte infections (skin/superficial infections)
SE
- multiple serious drug interactions
- edema, orthostatic htn, fatigue, insomnia, puritius, hot flashes, n/v
- need weekly monitoring of liver function
What might you use to treat a resistant systemic fungal infection?
Tri-azole antifungals such as Voriconazole and Posaconazole
