Antifungal drugs (add top 100)

Question 1

Ampothericin B is used for Systemic fungal infections. outline the information information regarding this drug

Answer 1

1) MHRA alert: fatal adverse reaction if formulations confused so both the complete generic name and the proprietary name should be used
2) Caution Anaphylaxis if given IV: Test dose first, Observe for 30 minutes after
3) Hepatic and renal function tests, blood counts, and plasma electrolyte monitoring required.
4) PRESCRIBE BY BRAND

Question 2

itraconazole is used for the treatment of candidiasis. outline some of the important information regarding this drug

Answer 2

1) Heart failure- caution in those at high risk of heart failure
2) Carbonated drinks, improves bioavailability. Take on an empty stomach
3) Potentially life-threatening hepatotoxicity - discontinue if signs of hepatitis develop.
4) Effective contraception during treatment and until the next menstrual period
5) recognise signs of liver disorder e.g. symptoms such as anorexia, nausea, vomiting, fatigue, abdominal pain or dark urine develop.

Question 3

Voriconazole is used in the treatment of Invasive aspergillosis. outline its main information

Answer 3

1) Hepatotoxicity- Hepatitis, cholestasis, and acute hepatic failure. Discontinue if LTFs show this
2) Phototoxicity- consider stopping if severe sunburn
3) Effective contraception
4) Monitor hepatic function before starting, at least weekly for 1 month then monthly. also renal function
5) keep the alert card with them at all times

Question 4

ketoconazole can be used in the treatment of fungal infections and Cushing’s syndrome. what are the important things to know about this drug?

Answer 4

1) risk of hepatotoxicity associated with oral ketoconazole stop patients unless being used for cushings
2) carbonated drinks improves bioavailability.
3) Monitor - ECG after 1 week, adrenal function - adrenal insufficiency, hepatic function
4) contraception in women of child-bearing potential

Question 5

what are antifungal drugs commonly indicated for?

Answer 5

1) local fungal infections, including of the oropharynx, vagina or skin. They may be applied topically (nystatin, clotrimazole) or taken orally (fluconazole).
2) Systemic treatment of invasive or disseminated fungal infections.

Question 6

outline the MoA of antifungal drugs

Answer 6

1) Polyene antifungals (e.g. nystatin) bind to ergosterol in fungal cell membranes, creating a polar pore which allows intracellular ions to leak out of the cell.
2) Imidazole (e.g. clotrimazole) and triazole antifungals (e.g. fluconazole) inhibit ergosterol synthesis, impairing cell membrane synthesis, cell growth and replication

Question 7

list the important side effects caused by antifungals

Answer 7

1) Fluconazole- GI upset, headache, hepatitis and hypersensitivity causing skin rash.
2) Rare but potentially life-threatening: hepatic toxicity; prolonged QT interval leading to arrhythmias
3) severe hypersensitivity, including cutaneous reactions and anaphylaxis.

Question 8

who should antifungals be used in caution with?

Answer 8

1) Topically administered nystatin and clotrimazole have no major contraindications.
2) Fluconazole caution in liver disease because of the risk of hepatic toxicity.
3) A dose reduction in moderate renal impairment
4) Avoid in pregnancy- risk of fetal malformation

Question 9

List the important interactions with regards to antifungals

Answer 9

1) Fluconazole inhibits CYT , causing an increase in carbamazepine, phenytoin, warfarin, diazepam, simvastatin and sulphonylureas.
2) It may reduce the antiplatelet actions of clopidogrel, a which requires activation by liver metabolism.
3) Risk of serious arrhythmias if prescribed with drugs that prolong the QT interval e.g. amiodarone, antipsychotics, quinine, quinolone and macrolides, SSRIs.