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Thursday, January 18, 2018

Comparison of oral antifungals



Availability in Hospital Keningau
  • Cap Fluconazole 50mg & 200mg
  • Tab Griseofulvin 125mg
  • Cap Itraconazole 100mg
  • Tab Ketoconazole 200mg 
  • Suspension Nystatin 100 000 units/ml
Comparison of Oral Antifungals
Antifungal
Indication (FUKKM)           
Pharmacokinetics
Ketoconazole
200mg
(B)
  • Pityriasis Versicolor
  • Systemic Mycoses (other skin mycosis)
  • Nail infection
  • Absorption can be increased by administration with a cola beverage (requires acidic condition)
  • Half life elimination is biphasic (initial 2 hours and terminal 8 hours)
Fluconazole 50mg

Fluconazole 100mg
(A)
  • Oropharyngeal candidiasis, atrophic oral candidiasis
  • Tinea Pedis, corporis, cruris, versicolor and dermal candidiasis
  • Invasive candida & cryptocococcal infections (includes meningitis)
  • Prevention of relapse cryptococcal meningitis in AIDS after completion of primary therapy
  • Prevention of fungal infections in immunocompromised patients
  • Oral bioavailability > 90%
  • The long serum half-life (approximately 24 hours) allows once-daily dosing
  • Good penetration into CSF
  • Absorption is not affected by the presence of food or gastric pH.
Itraconazole 100mg
(A/KK)
  • Dermatomycosis including pityriasis versicolor
  • Oral candidiasis
  • Palmar tinea manus and plantar tinea pedis
  • Fingernail onychomycosis
  • Toenail onychomycosis
  • Vulvovaginal candidiasis
  • Capsule bioavailability of approximately 55%
  • Relatively long half-life, approaching 25 to 50 hours thus allows OD dosing
  • Absorption increased by concurrent ingestion of cola or cranberry juice
Voriconazole 200mg

Voriconazole 50mg
(A*)
  • Treatment of immunocompromised patients with progressive, possibly life-threatening infections such as invasive aspergillosis, fluconazole-resistant serious invasive candidiasis, candidiasis of the oesophagus, serious fungal infections caused by Scedosporium species and Fusarium species
  • Prevention of breakthrough fungal infections in febrile high risk neutropenic patients

  • Oral biovailability >90% in adult and may vary with <12 year old
  • Ability to penetrate CSF



Syr. Nystatin
500 000
(B)
  • Prevention and treatment of candidiasis of the skin and mucous membranes
  • Protection against candidas overgrowth during antimicrobial /corticosteroid therapy and as selective decontamination regimens
  • Poorly absorbed
  • Excreted unchanged at feces 
  • Should be swished about the mouth and retained in the mouth for as long as possible (several minutes) before swallowing.
Griseofulvin
(B)
  • Dermatophyte infection of the skin, scalp, hair and nails, where topical therapy has failed or inappropriate
  • Absorption is almost complete (ultramicrosize)
  • Half life elimination is 9-24 hours
Flucytosine 500mg
(A*)
  • Only for the treatment of fungal meningitis
  • Ability to penetrate CSF
  • Bioavailability 78%-89% (decreased in neonates

Spectrum of activity



Imidazole (Ketoconazole)
  • Ketoconazole causes more gastrointestinal disturbances compared to other azoles.
  • Has been largely replaced by other triazoles due to favourable pharmacokinetic and safety profile
  • Should not be used as first-line treatment for any fungal infection.
  • It should be used for the treatment of endemic mycoses (eg, histoplasmosis, blastomycosis) only when alternative antifungal therapies are not available or tolerated.
  • Contraindicated in acute or chronic liver disease.
Triazole (Itraconazole, Fluconazole, Voriconazole)
  • The drugs in this class offer activity against many fungal pathogens without the serious nephrotoxic effects observed with amphotericin B 
  • Due to its inotropic effects, itraconazole’s labeling includes a black box warning in patients with heart failure, particularly in patients receiving a total daily oral dose of 400 mg
Pyrimidine (Flucytosine)
  • Flucytosine has limited clinical indication and is used primarily in combination with Amphotericin B as combination therapy for cryptococcal meningitis and selected life threatening Candida syndromes                 
References
  • Uptodate
  • https://mycology.adelaide.edu.au/docs/antifungals.pdf 
  • https://www.uspharmacist.com/article/the-fungus-among-us-an-antifungal-review 
  • Lexicomp 
  • FUKKM 

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