Transcript AntibioticsAntifunga..

Drugs used to treat infections caused by fungi
 Systemic
 Topical
 Very

large and diverse group of microorganisms
Broken down into yeasts and molds
 Fungal
infections also known as mycoses
 Some fungi are part of the normal flora of the
skin, mouth, intestines, vagina
 Reproduce by budding
 Can be used for


Baking
Alcoholic beverages
 Multicellular
 Characterized
called hyphae
by long, branching filaments
Four general types
Cutaneous
 Subcutaneous
 Superficial
 Systemic*

*Can be life threatening
*Usually occur in immunocompromised host
Candida albicans
Due to antibiotic therapy, antineoplastics,
or immunosuppressants (corticosteroids)
 May result in overgrowth and systemic infections
 Growth in the mouth is called thrush or oral candidiasis
 Common in newborn infants and immunocompromised
patients

Vaginal candidiasis
“Yeast infection”
 Pregnancy, women with diabetes mellitus, women taking
oral contraceptives

Systemic

amphotericin B, caspofungin, fluconazole, ketoconazole,
others
Topical

Examples: clotrimazole, miconazole, nystatin
Major groups based on their mechanisms of action
Polyenes: amphotericin B and nystatin
 Imidazoles: ketoconazole (Nizoral)
 Triazoles: fluconazole (Diflucan), itraconazole (Sporanox)
 Echinocandins: caspofungin (Cancidas), micafungin
 Listed individually, not by mechanism of action:


griseofulvin, flucytosine
Polyenes: amphotericin B and nystatin

Bind to sterols in cell membrane lining

Result: fungal cell death
Do not bind to human cell membranes or kill
human cells
 Use: Serious systemic fungal infections
 Administered: IV, PO, topical

Flucytosine (Ancobon)

Also known as 5-fluorocytosine (antimetabolite)

Taken up by fungal cells and interferes with DNA
synthesis

Result: fungal cell death

Use: Systemic mycoses due to Candida species
or Cryptococcus neoformans – administered
orally
Imidazoles and triazoles:
Ketoconazole (Nizoral), fluconazole (Diflucan)

Inhibit fungal cell cytochrome P-450 enzymes, resulting in cell membrane
leaking

Lead to altered cell membrane

Result: fungal cell death

Use: Ketoconazol (Nizoral): (po/topical): candidiasis, histoplasmosis,
coccidoidomycosis; cutaneous candidiasis; tinea infections

Use: fluconazole (Diflucan): (po/IV): systemic, oral, esophageal or vaginal
candidiasis; prevention of candidiasis after bone marrow transplant;
cryptococcal meningitis.
griseofulvin

Disrupts cell division

Result: inhibited fungal mitosis (reproduction)

Use: (po) Dermatophytosis (skin, hair, nails)
Echinocandins: capsofungin (Cancidas)

Prevent the synthesis of glucans, which are essential
components of fungal cell walls

Causes fungal cell death

Use: (IV) Invasive aspergillosis, Candidiasis
 Systemic
and topical fungal infections
 Drug
of choice for the treatment of many severe
systemic fungal infections is amphotericin B
 Choice
of drug depends on type and location of
infection
Fever / Headache
 Chills
 Dysrhythmias
 Malaise
 Nausea
 Hypotension
 Anorexia
 Muscle and joint pain
 Lowered potassium and magnesium levels
 Main concerns:
 *Renal toxicity
 *Neurotoxicity: seizures and paresthesias
 Many other adverse effects

Fluconazole (Diflucan)


Nausea, vomiting, diarrhea, stomach pain,
increased liver function studies
Flucytosine (Ancobon)

Nausea, vomiting, anorexia, headache, dizziness,
others
griseofulvin

Rash, urticaria, headache, nausea, vomiting,
anorexia, others
 Liver
 Renal
failure
failure
 Porphyria:
genetic disorder-erythrocyte
formation/liver dysfunction (griseofulvin)
 Many
antifungal drugs are metabolized by
the cytochrome P-450 enzyme system
 Co
administration of two drugs that are
metabolized by this system may result in
competition for these enzymes, and thus
higher levels of one of the drugs

Before beginning therapy, assess for hypersensitivity,
contraindications, and conditions that require cautious use

Obtain baseline VS, CBC, liver and renal function studies, and EKG

Assess for other medications used (prescribed and OTC) in order to
avoid drug interactions

Follow manufacturer’s directions reconstitution and administration

Monitor VS of patients receiving IV infusions every 15 to 30 minutes

During IV infusions, monitor I&O to identify adverse effects
amphotericin B

To reduce the severity of the infusion-related reactions,
pretreatment with an antipyretic (acetaminophen),
antihistamines, antiemetics, and corticosteroid may be
given

Use IV infusion pumps and the most distal veins possible

Some oral forms should be given with meals to decrease
GI upset; others require an empty stomach—be sure to
check

Nystatin given as an oral lozenge should be slowly and
completely dissolved in the mouth

(not chewed or swallowed whole)

Nystatin suspension should be swished thoroughly in
the mouth as long as possible before swallowing

Monitor for therapeutic effects
 Easing of the symptoms of infection
 Improved energy levels
 Normal vital signs, including temperature
Monitor carefully for adverse effects