Antifungal agents

1. Dr.Elza Joy Munjely
JR-I
Depmt. Of Pharmacology
Govt. Medical College,Kottayam.

2. Fungi- Eukaryotes

3. Cell wall- beta glucan and chitin
Cell membrane – ergosterol

4. 1. Yeasts – Crypyococcus
neoformans
2. Yeast –like fungi-
Candida albicans
3. Moulds-
Dermatophytes
4. Dimorphic fungi-
Blastomyces
dermatitidis, Histoplasma
capsulatum, Coccidioides
immitis, Sporothrix
Pathogenic Fungi Classification

5. Fungal infections – Mycoses
SUPERFICIAL-Black piedra
CUTANEOUS-Tinea
SUBCUTANEOUS-Sporotrix
SYSTEMIC-
Blastomycosis, Histoplasmosis, Coccidioidomycosis,
Cryptococcosis
OPPORTUNISTIC –
Mucor,Aspergillus,Candida

6. Classification based on mechanism of
action
1. Acting on fungal cell wall :
Echinocandins.
2. Acting on fungal cell membrane :
Polyenes,Azoles & Allylamine
3. Inhibition of nucleic acid synthesis: 5–
Flucytosine.

7. 4.Acting on mitotic spindle:
Griseofulvin.
5.Topical:
Ciclopirox, Tolnaftate, Haloprogin,
Undecylenic acid, Topical
azoles.

8. MECHANISM OF ACTION

10. ANTIFUNGALS
ALTERATION OF
CELL MEMBRANE
/ WALL PROPERTIES
BLOCK NUCLEIC
ACID SYNTHESIS
INHIBIT
MICROTUBULE
FUNCTION
Porin-
Formation
Synthesis
inhibitors
Polyene antibiotics
 Amphotericin B
 Nystatin
Flucytosine
Griseofulvin
1.Azoles
2.Allylamines
3.Glucan synthesis inhibitors
Mechanism of action of
Echinocandins

12. MOA of Polyenes

13. Amphotericin B
Binds ergosterol in fungal cell membrane
Form pores in cell membrane
Cell contents leak out
Cell death

14. Precursors
Squalene
Lanosterol
ergosterol
14--demethylase
Squalene epoxidase
Fungal cell membrane
AZOLES & ALLYLAMINES
Allylamines
Azole
antifungals

16. MOA of flucytosine

18. MOA of Griseofulvin
Binds to polymerised
microtubules and inhibit
mitosis

20. Squalene
Lanosterol
Ergosterol
Squalene
epoxide
14--
demethylase
5-FC
5-FU
5-FdUMP
dUMP dTMP
DNA
Cytosine
deaminase
Thymidylate
synthetase
microtubules
Pore
formation
Permease
Fungal cellwall
cell membrane
ECHINOCANDINS
AMPHOTERICIN B
ALLYLAMINES
AZOLES
GRISEOFULVIN
FLUCYTOSINE
FUNGAL CELL

21. Polyene antibiotics
 Amphotericin B:
 Streptomyces Nodosus
 Amphoteric
Lactone ring
Lipophilic part
Hydrophilic part

22. Antifungal spectrum
- Aspergillus
- Blastomyces dermatitidis
- Candida albicans
- Cryptococcus neoformans
- Coccidioides immitis
- Histoplasma capsulatum
- Mucor spp.
-
Broadest
spectrum of
action

23. Liposomes in the therapy of infectious
diseases and cancer 1989: 105
Antiprotozoal spectrum
•Leshmania
•Naegleria fowleri

24. Mechanism of resistance
Replacement of ergosterol by
other sterols in fungal plasma
membrane.

25. Pharmacokinetics
Poorly absorbed orally
Insoluble in water so
colloidal suspension
prepared with sodium
deoxycholate(1:1
complex)
t ½ = 15 days

26. Lıpıd formulations of amphotericin B
(ABLC; Abelcet®)
(ABCD; Amphocil® or Amphotec®)
(L-AMB; Ambisome®)
Amphotericin B Lipid Complex(ABLC)
Amphotericin B Colloidal Dispersion(ABCD)
Liposomal Amphotericin B

27. Ribbon-like particles
Carrier lipids: DMPC, DMPG
J Liposome Res 1993; 3:
451
AMB Lipid
complex
(ABLC):
ABLC

28. ABCD
AMB
colloidal
dispersion
(ABCD):

29. The ‘LIPOSOME’..
Hospital Practice 1992; 30: 53
•Liposomal
AMB (Small
unilamellar
vesicles) :

30. • Adverse events:
–Acute reaction:
–Long term toxicity:
–Nephrotoxicity:
–CNS toxicity :
–Anaemia
–Hepatotoxicity rarely

31. • Systemic mycotic infections
• invasive aspergillosis
• Rapidly progressive Blastomycosis &
Coccidiomycosis
• Mucormycosis.
• Disseminated rapidly progressing
Histoplasmosis
• Cryptococcus neoformans-intra
thecal
•Given as IV
Available as 50mg vial – suspended in 10 ml water and then diluted
with 500 ml glucose
Uses

32. Liposomes in the therapy of infectious
diseases and cancer 1989: 105
Release from
macrophage
Macrophage
Release in blood
compartment
Endocytosis
Liposome Lysosome
Fusion
Liposome
degradation
Endocytic
vesicle
Reserve drugs
for resistant
kala azar

33. Topical uses
 Intestinal Monoliasis: Orally
 Vaginitis
 Otomycosis: 3 % drops
 Mycotic infections of the bladder (bladder irrigation)

34. Nystatin
 S.Noursei
 locally
Uses:
 Intestinal moniliasis
 Vaginitis
 Prevention of oral candidiasis
 Oral, cutaneous, conjunctival
candidiasis

35. Hamycin:
 S. Pimprina
 Hindustan antibiotics
Topical use in thrush, cutaneous
candidiasis, trichomonas & monilial
vaginitis, otomycosis by aspergillus

36. Natamycin:
Broad spectrum
Used topically
Fusarium solani keratitis,
trichomonas & monilial vaginitis

37. AZOLES
Synthetic
Broad spectrum
Fungistatic or fungicidal
depending on conc of drug
 imidazoles & triazoles

38. Imidazoles:
 Two nitrogen in structure
 Topical: econazole, miconazole, clotrimazole
 Systemic : ketoconazole
 Newer : butaconazole, oxiconazole, sulconazole

39. Triazoles Three nitrogen in structure
 Fluconazole, itraconazole, voriconazole
Terconazole

40. SYSTEMIC TOPICAL
 Ketoconazole
 Fluconazole
 Itraconazole
 Voriconazole
 Clotrimazole
 Miconazole
 Econazole
 Oxiconazole
 Sertaconazole
 Terconazole
 Sulconazole
 Tioconazole
 Butaconazole

41. Imidazoles

42. Miconazole & clotrimazole
 Topical use:
 Miconazole 2 % and clotrimazole 1 %
 Uses:
 Dermatophyte infections
 Candida: oral pharyngeal, vaginal, cutaneous
 Adverse events:
 Local irritation

43. First orally effective
broad spectrum
antifungal
acidic
environment
favours
absorption
Csf penetration less
Ketoconazole

44. Adverse events of ketoconazole
↓ steroid, testosterone & estrogen
synthesis
Gynaecomastia, oligospermia ,
loss of libido & impotence in
males
Menstrual irregularities &
amenorrhoea in females

45. Drug Interactions of ketoconazole

46. Dangerous interaction with
terfenadine,astemizole and
cisapridePolymorphic
ventricular tachycardia

47. Ketoconazole and steroid
hormone synthesis
 Inhibit cholesterol side-chain
cleavage enzyme
17α-hydroxylase -which converts
cholesterol to pregnenolone
17,20-lyase ,which
convert pregnenolone into androgens
 11β-hydoxylase, which converts 11-
deoxycortisol to cortisol.

48. Uses of ketoconazole
Dermatophytosis: conc in
stratum corneum
Monilial vaginitis :
Systemic mycosis
Topical: T.pedis, cruris,
corporis, versicolor

49. Other uses of ketoconazole
Prostate cancer
Precocious puberty
Cushing syndrome
Hirsuitism

50. Triazoles

51. Fluconazole
 Broad spectrum
 Candida, cryptococcosis,
coccidiodomycosis
 Dermatophytosis
 Blastomycosis
 Histoplasmosis
 Sporotrichosis
 Oral, IV as well as topical
 Not effective against aspergillosis &
mucormycosis

52. Pharmacokinetics of fluconazole
Not affected by food or gastric
pH
crosses BBB –Fungal
meningitis

53. Adverse events of fluconazole
GIT upset
Less adverse effects than
ketoconazole
No anti androgenic & other
endocrine effects

54. Uses of fluconazole
 Candida:
 vaginal candidiasis- 150 mg oral dose
 Oral candidiasis- 2 weeks treatment required
 Tinea infections & cutaneous candidiasis:
• 150 mg weekly for 4 weeks
• tinea unguim : 12 months
 Systemic fungal infections:
Meningitis: preferred drug
 Eye drops for fungal keratitis

55. Itraconazole
Broad spectrum of activity
also against aspergillus
Does not inhibit steroid
hormone synthesis and no
serious hepatoxicity

56. Pharmacokinetics of itraconazole
 Absorption enhanced by food & gastric acidity
 Accumulates in vaginal mucosa, skin, nails
 CNS penetration is poor
 Metabolized in liver

57. Uses of itraconazole
DOC for paracoccidomycosis &
chromoblastomycosis ,
histoplasmosis & blastomycosis
Also used in oesophageal,
oropharyngeal vaginal candidiasis
Dermatophytosis
Onychomycosis
Aspergillosis

58. Adverse events of itraconazole
 Hypokalemia
 Increase plasma transaminase
 Drug interactions:
 Oral absorption ↓by antacids, H2 blockers

59. Voriconazole
High oral bioavailability
Good CSF penetration
Doesn’t require gastric acidity
for absorption

60. Uses of voriconazole
DOC for invasive aspergillosis
Most useful for esophageal
candidiasis
First line for moulds like
fusarium
Resistant candida infections

61. Adverse effects of voriconazole
Adverse events:
Transient visual changes like
blurred vision , altered color
perception & photophobia
Prolongation of QT

62. Posaconazole
Broadest spectrum azole
Liquid oral formulation
Dose : 800mg/day
Potent inhibitor of CYP-3A4

63. Indications -Posaconazole
Prophylaxis of invasive candidiasis
Salvage therapy for invasive
aspergillosis
Mucor mycosis & zygomycosis –
the only azole active!

64. Ravuconazole
Phase II clinical trial
Spectrum-
Candida sp
Aspergillus
Dermatophytes
Oral

65. Water
solubility
Absorption Halflife(hrs
)
Eliminatio
n
Formulatio
ns
Ketoconazole low variable 7-10 Hepatic Oral
itraconazole low variable 24-42 Hepatic Oral/IV
Fluconazole high high 22-31 Renal Oral/IV
Voriconazole high high 6 Hepatic Oral/IV
Posaconazole low high 25 Hepatic Oral

66. VORICONAZO
LE
POSACONAZOL
E
RAVUCONAZOL
E
Formulations ORAL/IV ORAL ORAL
T 1/2 6 hrs 25 hrs 100 hrs
Adverse effects liver enz
Visual S/E
GI upset
Hepatotoxic
Drug interactions High least

67. Terbinafine
Orally & topically effective
Fungicidal
Pharmacokinetics:
Well absorbed orally
Highly keratophilic & lipophilic
poor BBB permeability
t1/2- 15 days

68. Adverse events and uses
Adverse events:
Taste disturbances
Rarely hepatic dysfunction
Uses:
Dermatophytosis
Onychomycosis
Candidiasis

69. Other allylamines
Naftifine
 Dermatophytes,T.versicolor,cutaneous candidiasis
Butenafine

70. 5 flucytosine
Narrow spectrum
Prodrug, pyrimidine analog
Adverse events:
 Bone marrow toxicity , Alopecia,
rarely hepatitis
Uses: in combination with AMB in
cryptococcal meningitis

71. Advantages of
combination:
–Entry of 5 FC
–Reduced toxicity
–Rapid culture
conversion
–Reduced duration of
therapy
–Decreased
resistance

72. Griseofulvin
Penicillium griseofulvum
Fungistatic
 systemic drug for superficial
fungal infections
Active against dermatophytes
Dermatophytes concentrate it
actively hence selective toxicity

73. Pharmacokinetics:
Increased absorption by
fatty food
 keratinized tissue
t1/2=24 hrs

75.  Adverse events:
 Headache most common
 CNS symptoms: confusion, fatigue, vertigo
 Peripheral neuritis
 photoallergy
 Transient leukopenia, albuminuria

76.  Uses:
Systemically only for dermatophytosis,
ineffective topically
Duration of treatment depends on site,
thickness of keratin and turnover of
keratin.
Treatment must be continued till infected
tissue is completely replaced by normal
skin,hair, nail.
Dose: 125-250 mg QID

77. Duration of treatment
• Body skin = 3 weeks
• Palm, soles = 4- 6 weeks
• Finger nails = 4- 6months
• Toe nails = 8 – 12 months

78.  Interactions:
 Warfarin , OCP
 Phenobarbitone, Disulfiram like reaction

79. Echinocandins
 Spectrum
Candida
Aspergillus
NOT active againt Cryptococcus
PK
 Highly PPB
 Metabolites are eliminated by kidneys & GIT
 Available only as i/v formulations

80. Echinocandins
Adv
Broad -spectrum activity against all
Candida species
Relatively low toxicity-
among the safest

81. Caspofungin
FDA approved in 2001
Dose – single loading dose 70mg
followed by daily dose of 50mg iv
over 1 hr
Use
Invasive forms of candidosis
Candidemia
Invasive aspergillosis

82. Micafungin
FDA- approved in 2005
Candida esophagitis- 150 mg/day
Candidemia -100mg/day
Prophylaxis of fungal infections in
those receiving stem cell
transplant- 50mg/day
D/I
Micafungin -↑ the levels of
nifedipine,cyclosporine and sirolimus

83. Anidulafungin
FDA approved in2006
Candida esophagitis-
100mg 1st day followed by 50mg/day
Candidemia-
200mg 1st day followed by
100mg/day

84. Adverse Effects
 Flushing , phlebitis-Anidulafungin
 Increase in liver enz.
 GI disturbances Caspofungin

85. Topical agents used in dermatophytosis
 Tolnaftate:
 Tinea infections.
 Not effective in hyperkeratinized lesions
 Salicylic acid aids its effect by keratolysis

86. Topical agents used in dermatophytosis
 Ciclopirox olamine:
 Tinea infections, pitryasis versicolor
,dermal candidiasis, vaginal
candidiasis
 Penetrates superficial layers

87. Topical agents used in dermatophytosis
Undecylenic acid: 5% (Tineafax)
Generally combined with zinc (20%)
used in tinea cruris and nappy rash
Sodium thiosulfate: (Karpin lotion)
Reducing agent known as hypo
Effective in pitryasis versicolor only
20 % solution for 3-4 weeks

88. Topical agents used in dermatophytosis
 Benzoic acid:
 Used in combination with salicylic acid
 Whitfields ointment: ( benzoic acid 6% +
salicyclic acid 3 %)
 Salicyclic acid due to its keratolytic action
helps to remove infected tissue &
promotes penetration of benzoic acid in
fungal infected lesion
 Adverse events: irritation & burning
sensation
(Ring cutter ointment)

89. Topical agents used in dermatophytosis
Haloprogin
 Dermatophytosis
 Mainly-T.pedis

90. Topical agents used in dermatophytosis
Quinidiochlor;
Luminal amoebicide
Weak antifungal & antibacterial
External application :
dermatophytosis , mycosis barbae,
pitryasis versicolor
Selenium sulfide: T. versicolor
 Potassium iodide: Dermatophytic
infection

91. Spectrum of action
Nystatin: Candidiasis only
Griseofulvin: Dermatophytosis only
Terbinafine : Dermatophytosis &
candidiasis
Caspofungin: Aspergillosis & candidiasis

92. Important characteristics
• Broad spectrum: AMB, KTZ, FLU, ITR
• Nephrotoxic/ Anemia: AMB
• Leucopenia: 5 FC
• GIT upset: All
• Over all toxicity: highest for AMB
lowest for fluconazole, itraconazole