ANTIFUNGAL DRUGS Flashcards
• Produced by Streptomyces nodosus
• Highly effective, a mainstay, in serious invasive & deep-
seated infections
• Toxicto kidneys - many side effects or adverse drug reactions
AMPHOTERICIN B
• Amphoteric polyene (many double bonds) macrolide (containing a large lactone ring of ≥ 12 atoms)
• Nearly insoluble in water
• Conventionally, the first preparation is as a colloidal
suspension of AmB + Na deoxycholate for IV injection
AMPHOTERICIN B
Advantages:
• ↑ daily dose of parent drug
• ↑ tissue conc. in the RE organs
• ↓ infusion related side effects
• Marked ↓ in nephrotoxicity
• Amphotericin B Liposomal (L-AmB)
• Amphotericin B Cholesteryl Sulfate
• Amphotericin B Lipid Complex (ABLC)
• Poorly absorbed from GIT
• Oral AmB
- Only used for luminal fungi
- Not for systemic disease
AMPHOTERICIN B
• Wide tissue distribution
• Unfortunately, only 2-3% penetrates CSF
- Need intrathecal
AMPHOTERICIN B
• Mode of Action:
- Affinity for ergosterol found in fungi cell membrane →→
pore formation → leakage of IC ions & macromolecules →
cell death
AMPHOTERICIN B
• Broadest spectrum of action. Fungicidal.
AmB ANTIFUNGAL ACTIVITY & CLINICAL USES
• Often used as induction therapy to rapidly reduce fungal burden (then replaced by newer azole drugs for chronic Tx or relapse prevention)
AmB ANTIFUNGAL ACTIVITY & CLINICAL USES
Adverse effects of AmB
Infusion Related Toxicity – immediate
Cumulative Toxicity – slow occurring
● Immediate/Rapid
● Nearly universal
○ Fever, chills, muscle spasms, vomiting, headache, low BP might manifest while infusing AmB
● Ameliorated by slowing down or low infusion rate or low daily dose
● Premedication with antipyretics, antihistamines, Meperidine, corticosteroids
● Test dose of 1 mg IV to gauge severity of reaction
INFUSION RELATED TOXICITY
Slow occurring
● More serious AE
● Renal damage or nephrotoxicity most significant and in almost all patients
○ Variable azotemia
- Azotemia: increase in BUN and
creatinine
- can be stabilized or will need renal
replacement therapy like dialysis
● Reversible: low renal perfusion (prerenal)
● Irreversible component:
○ AmB is very notorious for Tubular
injury associated with prolonged Tx (>4 grams cumulative dose)
CUMULATIVE TOXICITY
increase in BUN and creatinine
AZOTEMIA
Water soluble pyrimidine analog related to
5-Fluorouracil (5-FU) used for treating cancer.
FLU(ORO)CYTOSINE
Exhibit synergism with AmB and Itraconazole for
CNS Fungal Infection.
FLU(ORO)CYTOSINE
- Mainly used for CNS Infections
2.Cryptococcal meningitis Cryptococcus
neoformans(COMBINED WITH AMP B) - UTI (IF RESISTANT TO FLUCONAZOLE)
FLU(ORO)CYTOSINE