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MOST COMMONLY PRESCRIBED ANTIFUNGAL AND ANTIVIRAL MEDICATIONS Anneliese Bodding-Long University of Washington Doctor of Pharmacy Candidate, 2012

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Presentation on theme: "MOST COMMONLY PRESCRIBED ANTIFUNGAL AND ANTIVIRAL MEDICATIONS Anneliese Bodding-Long University of Washington Doctor of Pharmacy Candidate, 2012"— Presentation transcript:

1 MOST COMMONLY PRESCRIBED ANTIFUNGAL AND ANTIVIRAL MEDICATIONS Anneliese Bodding-Long University of Washington Doctor of Pharmacy Candidate, 2012

2 OBJECTIVES Identify the commonly prescribed antifungal and antiviral medications, their mechanism of action, and what they are commonly prescribed for Explain common counseling points for each class Identify the specific counseling points, side effects, and toxicities of these medications

3 ANTIVIRALS Influenza: Oseltamivir Herpes Simplex/ Herpes Zoster: Acyclovir Valacyclovir Famciclovir

4 VIRAL UPPER RESPIRATORY INFECTIONS OR “THE COMMON COLD” Caused by more than 200 viruses Rhinovirus, influenza, coronavirus, respiratory syncytial virus, etc. Virus replicates and “sheds” Symptoms and shedding usually last 3-7 days Most contagious the day before fever begins through 24 hours after fever ends Symptoms Nasal congestion, non-productive cough, fever, muscle aches, sore throat

5 WHEN TO TREAT THE COMMON COLD? Empiric use of antibiotics More harm than good? Unnecessary adverse effects? Increase bacterial resistance? “My snot’s yellowish-green, not clear. Is it bacterial?” Should we culture, and is it an infection or normal colonization? Cultures may take a few days to return from lab, pt often already has begun antibiotic treatment Rapid tests for influenza- results in 1 hr Can’t use if symptoms > 3 days, or recent LAIV False negatives and low sensitivity Expensive Antibiotic therapy does help those infections with a positive culture for the “big three” bacterial suspects H. influenzae, M. catarrhalis, or S. pneumoniae Antibiotics are important to prevent secondary infections Pneumonia, otitis media, bronchitis, sinusitis

6 WHEN TO PROPHYLAX/TREAT INFLUENZA WITH AN ANTIVIRAL? High risk populations: ≥65 years old Pregnant women Chronic medical conditions Diabetes, asthma, COPD, cardiovascular disease, etc Asplenic patients Influenza requiring hospitalization Prevent outbreak Nursing homes, long-term care facilities, correctional facilities

7 ANTIVIRALS FOR INFLUENZA Oseltamivir (Tamiflu®) Oral capsule Oral suspension

8 MECHANISM OF ACTION Oseltamivir : inhibits influenza virus neuraminidase which stops viral particle release LAYMEN’s terms: prevents the infected host cell from releasing new virus

9 OSELTAMIVIR INDICATIONS Influenza A & B H1N1 Avian (H5N1) Prophylaxis should begin hr after exposure for best effect Continue for 10 days QD therapy Prophylaxis is NOT replacement for vaccine Influenza A & B H1N1 Avian (H5N1) Treatment should begin ASAP, or hr after onset of symptoms Continue for 5 days BID therapy Oseltamivir resistance? Zanamivir ProphylaxisTreatment

10 OSELTAMIVIR PATIENT INFORMATION Administration: Take with or without food Food may decrease GI upset Suspension: Shake well Store in fridge Contraindications No live vaccines w/in 2 weeks before or 48 hours after What to expect: Improvement of symptoms May shorten duration of flu symptoms by 1-3 days May decrease risk of transmission to others Reduction in secondary antibiotic use

11 HERPES INFECTIONS HSV1 Herpes labialis or “cold sores”, fever blisters HSV2 Genital herpes Acquired through sexual contact, lifelong recurrent infection Can by asymptomatic, still transmissible Herpes Zoster Varicella zoster virus Causes chicken pox in children, shingles, and postherpetic neuralgia

12 ANTIVIRALS FOR HERPES INFECTIONS Acyclovir (Zovirax®) Oral capsule, tablet, and IV Oral suspension Topical cream, ointment Valacyclovir (Valtrex®) Oral tablet Famciclovir (Famvir®) Oral tablet

13 MECHANISM OF ACTION Acyclovir : acts as a purine nucleotide analog to interfere with herpes viral DNA polymerase Valacylovir: Prodrug converted to acyclovir Famciclovir: Prodrug converted to penciclovir (acts similarly to acyclovir) LAYMEN’s terms: interferes with viral DNA replication by terminating the DNA chain

14 INDICATIONS Acyclovir Herpes Labialis (topical) Genital Herpes Initial, Recurrent, Chronic Suppression Herpes Zoster (shingles) Varicella-zoster (chicken- pox) Valacyclovir Herpes Labialis Genital Herpes Initial, Recurrent, Reduction of Transmission, Chronic Suppression Herpes Zoster Varicella-zoster Famciclovir Herpes Labialis Genital Herpes Initial, Recurrent, Chronic Suppression Herpes Zoster

15 COMMON COUNSELING POINTS Take with or without food Take with extra fluids Tell patients to drink enough to urinate every few hours Topical application: Use gloves, wash hands Cover lesion, rub on gently Adverse Effects with oral medication: Headache, fatigue N/V/D/constipation More SE with Herpes Zoster treatment (increased dose)

16 COMMON COUNSELING POINTS, CONT If taking chronically, explain importance of adherence to prevent outbreaks Cost of therapy? Covered by insurance? Reduction of stressors (may increase risk of outbreak) Pts concerned should know toxicity of long-term therapy is minimal Explain that this is not a cure, give realistic expectations If taking medication episodically for genital herpes, take within 24 hours of outbreak symptoms (tingling) to suppress or reduce duration and severity Reduces pain, length of time to healing, viral shedding Practice SAFE SEX Chronic therapy does reduce transmission risk Use condom, avoid sex during outbreak

17 SPECIFIC PATIENT INFORMATION Valacyclovir and famciclovir have longer half- lives than acyclovir, take less frequently Example : Acyclovir 5 times a day x 5 days Valacyclovir 2 times a day x 3 days May increase patient adherence to chronic med Acyclovir and valacyclovir Drug-Drug Interaction with probenicid May increase levels of these antivirals, increase side effects

18 ANTIFUNGALS

19 FUNGAL INFECTIONS Superficial Infections Tinea (dermatophyte) infections Named for site of infection Tinea pedis, corporis, cruris, capitus, etc Onychomycosis Infection of finger/toenails by dermatophytes Sebborrheic dermatitis Vaginal candidiasis (yeast infection) Most common species is C. albicans, though other spp are on the rise Antibiotic treatment can lead to overgrowth OTC treatment possible if uncomplicated

20 FUNGAL INFECTIONS, CONT. Oropharyngeal (thrush) and Esophageal candidiasis Infectioncan spread from oral mucosa into esophagus Risk factors include antibiotics, inhaled steroids, dentures, smoking, immunocompromised patients Systemic and Opportunistic Infections Can gain entry through GI, lungs, or IV Systemic candidiasis Can include peritonitis, pneumonia, and others

21 ANTIFUNGAL MEDICATIONS Azoles Imidazoles: ketoconazole Triazoles: fluconazole, itraconazole, voriconazole Terbinafine Nystatin

22 MECHANISM OF ACTION Triazoles: inhibition of CYP450 enzyme dependent ergosterol synthesis Ketoconazole and Terbinafine: interfere with fungal ergosterol biosynthesis Nystatin: binds to sterols in cell membrane and changes permeability LAYMEN’s terms: prevents proper production of fungal cell membrane resulting in cell death

23 AZOLES Ketoconazole (Nizoral®) Oral tablet & topicals: cream, gel, shampoo, foam Fluconazole (Diflucan®) Oral tablet and IV Itraconazole (Sporanox®) Oral capsule Voriconazole (VFEND®) Oral tablet and IV

24 OTHER ANTIFUNGALS Terbinafine (Lamisil®) Oral tablets Topicals: cream, gel, solution Nystatin (Nystat- RX®) Oral tablets Oral suspension Vaginal tablets Topical powder

25 MOST COMMON INDICATIONS Tinea Infections (1-4 wks) Ketoconazole Terbinafine Onychomycosis (6wks-1yr) Itraconazole Terbinafine Vaginal Candidiasis (1d- 2wks) Fluconazole Nystatin Oropharyngeal Candidiasis (7-14d) o Fluconazole o Itraconazole o Nystatin Esophageal Candidiasis (14-21d) o Fluconazole o Itraconazole o Voriconazole Systemic Infections Fluconazole Voriconazole Nystatin

26 PATIENT INFORMATION FOR ALL ANTIFUNGALS Administration Superficial fungal infections may take a LONG time to effectively treat (weeks to months) Exception -Fluconazole for vaginal yeast infection Important to counsel on adherence and time to effect Onychomycosis Side Effects Oral: Headache, dizziness, changes in taste GI upset: N/V/D Can take with food to prevent Exception - take voriconazole 1-2 hrs before meal Topical: Irritation, burning, and dryness Reminder to wash hands after administration

27 SPECIFIC PATIENT INFO Contraindications Azoles and Terbinafine can lead to liver toxicity so liver function should be closely monitored [US Black Box Warning] Azoles (especially triazoles) have drug interactions since MOA involves P450 enzymes Inhibit CYP3A4, 2C9, 2C19 (warfarin, phenytoin, benzodiazepines…) Terbinafine also exhibits drug interactions inhibits CYP2D6 (antidepressants, codeine…) Ketoconazole and Itraconazole : separate from antacids by 2 to 4 hours. Why? Voriconazole: may cause visual disturbances, photophobia Itraconazole: take with food to increase absorption

28 QUESTIONS?

29 QUIZ NEXT WEEK: Know COMMON counseling points about the classes of antifungals and antivirals Know the drugs in each class and their mechanisms of action (Laymen’s terms ok) Know some SPECIFIC counseling points, side effects, and toxicities for these medications *Hint* look at items in bold or all caps

30 FEEDBACK! Please take out a ½ sheet of paper and respond to these questions: 1) What was the most useful information you learned today? 2) What questions remain about the lecture material? 3) What constructive feedback to you have? THANK YOU!


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