Chapter 8: Antifungal and Antiviral Agents

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Questions and Answers

What is the mechanism of action of Nystatin as an antifungal agent?

Inhibits nucleic acid synthesis

Inhibits protein synthesis

Interferes with cell wall synthesis

Binds to sterols in the cell membrane (correct)

Which of the following fungal infections is NOT commonly caused by Candida Albicans?

Athlete's foot (correct)

Oropharyngeal candidiasis

Oral Thrush

Tinia infections

What is the recommended method of application for Nystatin for effective treatment?

Topically (correct)

Intravenously

Inhalation

Orally as a tablet

What type of infections do Imidazoles, such as Clotrimazole, primarily target?

Fungal infections Signup and view all the answers

What dosage range is recommended for Ketoconazole when treating mucocutaneous candidiasis?

200-400 mg PO daily Signup and view all the answers

For Clotrimazole, what is a notable concern when using its lozenge form in patients with Xerostomia?

It may be difficult to dissolve Signup and view all the answers

Which antifungal agent is recommended for patients who have not responded to other treatments for candidiasis?

Ketoconazole Signup and view all the answers

Which of the following is a common side effect associated with Ketoconazole when taken orally?

Nausea and GI effects Signup and view all the answers

What is the primary role of protease inhibitors in viral replication?

To prevent viral replication Signup and view all the answers

Which of the following is commonly associated with the side effects of injectable antiviral agents?

Pain, itching, and swelling at the injection site Signup and view all the answers

What is the purpose of using Highly Active Antiretroviral Therapy (HAART)?

To manage HIV and AIDS Signup and view all the answers

What is PEP and when should it be initiated after exposure to HIV?

Post Exposure Prophylaxis, within 72 hours Signup and view all the answers

Which of the following enzymes is integral to the replication of the HSV virus?

Integrase Signup and view all the answers

What type of hepatitis is characterized by inflammation of the liver lasting more than six months?

Chronic Hepatitis Signup and view all the answers

Which treatment is known to generally suppress hepatitis virus effectively?

Nucleoside Analogs Signup and view all the answers

What are common adverse reactions associated with Nevirapine (NVP)?

CNS effects, headache, and drowsiness Signup and view all the answers

What is the primary action of Acyclovir in treating herpes simplex virus (HSV)?

Inhibits DNA synthesis Signup and view all the answers

Which of the following side effects is commonly associated with Acyclovir?

Excessive fatigue Signup and view all the answers

Which statement about the transmission of HSV viruses is accurate?

Both HSV 1 and HSV 2 are transmitted similarly. Signup and view all the answers

Which antiviral medication is available without a prescription for HSV 1 lesions?

Docosanol Signup and view all the answers

What is the absorption range for Acyclovir when taken orally?

10-30% Signup and view all the answers

Which class of medications is NOT typically used in the treatment of AIDS?

Non-steroidal anti-inflammatory drugs (NSAIDs) Signup and view all the answers

What is a notable characteristic of famciclovir in relation to acyclovir?

It is prescribed when acyclovir is ineffective. Signup and view all the answers

What effect does Acyclovir have on host cells when treating viral infections?

It damages host cells when killing the virus. Signup and view all the answers

Study Notes

Fungal Infections

Fungal infections are notoriously challenging to treat due to similarities with human cells.
Common oral fungi include Candida Albicans and Tinia infections.
Individuals with underlying health conditions are more susceptible to fungal overgrowth.

Types of Fungal Infections

Mucocutaneous: Localized effects on body surfaces.
Systemic: Internal organ effects caused by fungi in the bloodstream.

Antifungal Agent: Nystatin

Produced by Streptomyces Noursei, nystatin is a prescription antifungal.
Exhibits both fungicidal and fungistatic properties.
Mechanism: Binds to sterols in the cell membrane, increasing permeability and causing loss of cell contents.
Poorly absorbed orally; topical application is more effective.
Commonly used for oral candidiasis as a mouthwash solution.
Creams administered for 10-14 days or 48 hours post-symptom resolution.
Brand names include Myostatin and Nilstat.

Imidazoles

Clotrimazole: Available as a sugar-containing lozenge (Troches) recommended for patients with xerostomia, used 5 times daily for 10-14 days.
Troches contain gelatin, suitable for dietary restrictions.
Effective for skin infections; available in cream and topical forms.
Mechanism: Binds with phospholipids in the cell membrane, enhancing permeability and causing loss of cell contents.
Miconazole: Another important imidazole antifungal.

Ketoconazole

Effective against Candida and used when other treatments fail.
Treats mucocutaneous and oropharyngeal candidiasis (oral thrush).
Available as an oral tablet, may cause nausea and gastrointestinal effects.
Also offered in cream form.
Brand name Nizoral treats athlete's foot, jock itch, ringworm, and anti-dandruff.
Dosage: 200-400 mg orally daily for 2 weeks to up to 12 months.

Other Imidazoles

Diflucan (Fluconazole) is taken orally as a tablet for serious candidiasis infections and other conditions like vaginal and urinary tract infections.

General Information on Viral Infections

Viruses replicate only in the presence of a host.
Antiviral medications inhibit viral DNA synthesis and replication.
Eliminating viruses can harm host cells; viruses remain inactive or latent rather than completely removed.

Herpes Simplex Virus (HSV)

HSV1 causes cold sores and can appear in nail beds and fingers, termed herpetic whitlow.
HSV2 predominantly affects the genital area but both types can be transmitted from either site.
Highly contagious; avoid treating clients with active oral lesions.

Treatment Options for HSV

Acyclovir
- Inhibits DNA synthesis, absorbed by infected cells.
- Available orally (10-30% absorption) or topically; side effects include burning, mild pain, itching, and rash.
- Does not prevent reinfection or viral contagion.
Docosanol (Abreva)
- Specifically targets HSV1 lesions.
- Speeds up recovery from oral HSV lesions; available over the counter.
Famciclovir / Valacyclovir
- Prescription medication for strains resistant to acyclovir.
- Effective against acute infections like Varicella Zoster.

HIV/AIDS and HSV

HIV leads to progressive damage to host cells; impacted individuals require multiple antiviral treatments.
Opportunistic infections are common in AIDS patients.

Transmission of HSV and AIDS

HSV1 and HSV2 can be transmitted through sexual intercourse, body fluids, and childbirth.
Mother-to-child transmission occurs only during pregnancy.

Antiviral Treatments for AIDS

NRTIs (Nucleoside/Nucleotide Reverse Transcriptase Inhibitors)
- Bind to the reverse transcriptase enzyme, preventing viral replication.
Protease Inhibitors
- Block protease activity, hindering virus replication.
Fusion/Entry Inhibitors
- Prevent virus entry into human cells.
Integrase Inhibitors
- Prevent integration of viral genome into host cells, stopping replication.
Highly Active Antiretroviral Therapy (HAART) often involves a combination of three drugs.

Post-Exposure Prophylaxis (PEP)

Following potential HIV exposure, treatment should commence within 72 hours for 28 days with Truvada plus Raltegravir.

Chronic Hepatitis

Most common types are Hepatitis B and C, accounting for about two-thirds of all hepatitis cases.
Chronic hepatitis is defined as lasting longer than six months.

Hepatitis Treatment Options

Nucleoside Analogs
- Suppress hepatitis virus with generally good tolerance and treatment lasting up to five years.
Interferons
- Injectable endogenous proteins used to treat hepatitis.
Protease Inhibitors
- Effective in increasing virologic response specifically for Hepatitis C.

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Description

Explore the complexities of treating fungal infections in Chapter 8. This quiz covers the challenges posed by fungi, common types such as Candida Albicans and Tinia, and the impact of underlying health conditions on susceptibility. Test your understanding of mucocutaneous and systemic fungal infections.