1. Antifungal Agents
Chapter 11

2. How Fungus Differs from Bacteria
Composed of a rigid cell wall made up of chitin and various polysaccharides, and a cell membrane containing ergosterol.
Protective layers of the fungal cell make the organism resistant to antibiotics.

3. Patients Susceptible to Fungal Infections
Patients with AIDS and AIDS-related complex (ARC)
Patients taking immunosuppressant drugs
Patients who have undergone transplantation surgery or cancer treatment
Members of growing elderly population no longer protected from environmental fungi

4. Culture
A culture should be obtained prior to prescribing anti-fungal agents.
Patients on antifungal agents are typically immunosuppressed.

5. Amphotericin B Indications
Aspergillosis the use is reserved for
Leishmaniasis progressive, potential
Cryptococcosis fatal infections due to
Blastomycosis many adverse effects
Moniliasis
Coccidioidomycosis
Histoplasmosis
Mucormycosis
Candida infections (topically)

6. Amphotericin B
Indications - Progressive potential fatal fungal infections
Pharmacokinetics - IV form, excreted in the urine
Contraindications - Kidney disease
Adverse Reaction - Kidney failure

7. Systemic Antifungal Agents
Caspofungin (Cancidas) (IV)
Approved for the treatment of invasive aspergillosis in patients who are refractory to other treatments
Flucytosine (Ancobon) (Oral)
Less toxic drug used for the treatment of systemic infections caused by Candida or Cryptococcus
Nystatin (Mycostatin, Nilstat) (Oral)
Used for the treatment of intestinal candidiasis; also available in a number of topical preparations

8. Voriconazole and Terbinafine
Newer Agents
Voriconazole (Vfend)
Available in oral and IV forms
Treats invasive aspergillosis and serious infections caused by Scedosporium apiospermum, or Fuscariium species
Terbinafine (Lamisil)
Blocks the formation of ergosterol
Inhibits a CYP2D6 enzyme system
Oral drug for the treatment of onychomycosis of the toenail or fingernail

9. Azoles Newer class of drugs used to treat systemic fungal infections
Less toxic than amphotericin B
Less effective than amphotericin B

10. Question
Please answer the following statement as true or false. Nystatin, taken orally, is used for the treatment of intestinal candidiasis.

11. Rationale: Nystatin (Mycostatin, Nilstat) (Oral)
Answer
True
Rationale: Nystatin (Mycostatin, Nilstat) (Oral)
Used for the treatment of intestinal candidiasis; also available as a topical preparation.

12. Ketoconazole (Nizoral)
Used orally to treat many of the same mycoses as amphotericin B
Works by blocking the activity of a steroid in the fungal wall
Has side effect of blocking the activity of human steroids, including testosterone and cortisol

13. Ketoconazole (Nizoral) (cont.)
Pharmacokinetics – Absorbed from the GI tract, metabolized in the liver, excreted in the feces
Contraindications – Not drug of choice for patients with endocrine or fertility problems
Adverse Reactions – Hepatic toxicity
Drug-Drug Interactions – Many (ex: digoxin, warfarin, CCB, antacids, fentanyl)

14. Fluconazole (Diflucan)
Not associated with the endocrine problems seen with ketoconazole
Used to treat candidiasis, cryptococcal meningitis, and other systemic fungal infections
Prophylactic agent for reducing the incidence of candidiasis in bone marrow transplant recipients

15. Fluconazole (Diflucan) (cont.)
Pharmacokinetics - Available in oral and IV preparations, excreted unchanged in the urine.
Contraindications – Renal dysfunction
Adverse Reactions – Liver or renal toxicity
Drug-Drug Interactions – Inhibits CYP450 may be associated with drug–drug interactions

16. Itraconazole (Sporanox)
An oral agent used for the treatment of assorted systemic mycoses
Associated with hepatic failure
Is slowly absorbed from the GI tract and is metabolized in the liver by the CYP450 system
Is excreted in the urine and feces

17. Site of Action of Antifungals

18. Overall Contraindications to Systemic Antifungal Agents
Patient’s with a known allergy
Pregnant or lactating women (with the exception of terbinafine for life-threatening infections)
Patients with renal or liver disease
May alter drug metabolism and excretion. Condition may worsen as a result of drug actions.

19. Overall Adverse Reactions to Systemic Antifungal Agents
CNS Effects
Headache, dizziness, fever, shaking, chills
GI Effects
Nausea, vomiting, dyspepsia, anorexia
Hepatic Dysfunction
Dermatological Effects
Rash and pruritus associated with local irritation
Renal Dysfunction

20. Question
Which of the following is considered a contraindication of Ketoconazole ? A. Patients with renal problems B. Patients with fertility problems C. Patients with hepatic problems D. Patients with GI problems

21. B. Patients with fertility problems
Answer
B. Patients with fertility problems
Rationale: Contraindications – not drug of choice for patients with endocrine or fertility problems.

22. Topical Antifungal Infections
Caused by dermatophytes
Tinea Infections (Ringworm)
Athlete’s foot (tinea pedis)
Jock itch (tinea cruris)
Candida
Yeast infections of the mouth and vagina

23. Topical Antifungal Agents (cont.)
Action/Indication
Work to alter the cell permeability of the fungus, causing prevention of replication and fungal death
Indicated only for local treatment of mycoses, including tinea infections
Contraindication/Cautions
Limited to known allergy to any of these drugs

24. Topical Antifungal Agents (cont.)
Adverse Effects
Local effects include irritation, burning, rash, and swelling
When taken as a suppository or troche: nausea, vomiting, hepatic dysfunction, urinary frequency and burning, and change in sexual activity
Drug-to-Drug Interactions
No reported drug–drug interactions

25. Prototype Antifungal Agent

26. Prototype Antifungal Agent

27. Prototype Antifungal Agent (Continued)

28. Use of Antifungals Across the Life Span

29. Nursing Considerations for Systemic Antifungal Agents
Assessment: History and Physical Exam
Nursing Diagnosis-page 169 (Acute pain r/t GI, CNS, and local effects of the drug; Disturbed Sensory Perception r/t CNS effects)
Implementation-page 169 (appropriate C&S tests prior to beginning therapy, administer entire course of drug-could take as long as 6 months, monitor renal and hepatic function, freq small meals…)
Evaluation-page 170 (monitor response to therapy, monitor for adverse effects)

30. Nursing Considerations for Topical Antifungal Agents
Assessment: History and Physical Exam-page 172 (assess for known allergies, complete physical assessment, perform C&S)
Nursing Diagnosis-Page 173 (Acute pain r/t local effects of the drug, knowledge deficit regarding drug therapy)
Implementation-page (culture effected area before beginning therapy to identify the causative fungus, ensure patient take the complete course of the drug regimen...)
Evaluation-page 174 (monitor patient reponse to the drug, monitor for adverse effects, monitor effectiveness of teaching plan...)

31. Question
The nurse is caring for a patient with a fungal infection. Which of the following would be considered an adverse effect of an antifungal medication? A. Burning or irritation in the sexual partner B. Abnormal kidney function tests C. Upper abdominal pain D. Urinary retention

32. Answer
A. Burning or irritation in the sexual partner Rationale: Adverse effects: Troche: nausea, vomiting, abnormal liver function tests; topical: stinging, redness, urticaria, edema; vaginal: lower abdominal pain, urinary frequency, burning or irritation in the sexual partner