The synthetic triazoles include:
• fluconazole
• itraconazole
• voriconazole.
合成三唑类药包括:氟康唑、伊曲康唑、伏立康唑。
Fluconazole belongs to a class of synthetic, broad-spectrum triazoles and is also referred to as a bistriazole antimycotic drug. Itraconazole and voriconazole also belong to the synthetic triazole class of drugs. They inhibit the synthesis of ergosterol, a vital component of fungal cell membranes.
Pharmacokinetics
After oral administration, fluconazole is about 90% absorbed. It’s distributed into all body fluids, and more than 80% of the drug is excreted unchanged in urine.
Oral bioavailability is greatest when itraconazole is taken with food; voriconazole is more effective if taken 1 hour before or after a meal.
Itraconazole and voriconazole are bound to plasma proteins and extensively metabolized in the liver into a large number of metabolites. They’re minimally excreted in stool.
Pharmacodynamics
Fluconazole inhibits fungal cytochrome P-450, an enzyme responsible for fungal sterol synthesis, causing fungal cell walls to weaken. Itraconazole and voriconazole interfere with fungal cell-wall synthesis by inhibiting the formation of ergosterol and increasing cell-wall permeability, making the fungus susceptible to osmotic instability.
Pharmacotherapeutics
Fluconazole is used to treat mouth, throat, and esophageal candidiasis and serious systemic candidal infections, including UTIs, peritonitis, and pneumonia. It’s also used to treat cryptococcal meningitis.
Itraconazole is used to treat blastomycosis, nonmeningeal histoplasmosis, candidiasis, aspergillosis, and fungal nail disease. Voriconazole is used to treat invasive aspergillosis and serious fungal infections caused by Scedosporium apiospermum and Fusarium species.
Drug interactions
Fluconazole may have interactions with other drugs:
• Using fluconazole with warfarin may increase the risk of bleeding.
• It may increase levels of phenytoin and cyclosporine.
• It may increase the plasma levels of oral antidiabetic drugs, such as glyburide, tolbutamide, and glipizide, increasing the risk of hypoglycemia.
• Rifampin and cimetidine enhance the metabolism of fluconazole, reducing its plasma level.
• Fluconazole may increase the activity of zidovudine.
Itraconazole and voriconazole may have these interactions:
• Both may increase the risk of bleeding when combined with oral anticoagulants.
• Antacids, H2-receptor antagonists, phenytoin, and rifampin lower plasma itraconazole levels.
• Voriconazole may inhibit the metabolism of phenytoin, benzodiazepines, calcium channel blockers, sulfonylureas, and tacrolimus.
• Voriconazole is contraindicated with sirolimus and ergot alkaloids because voriconazole may increase plasma levels of sirolimus and ergots.
• Voriconazole is contraindicated with quinidine and pimozide because of the risk of prolonged QT interval and, rarely, torsades de pointes.
triazole – n. 三唑类药
fluconazole – n. 氟康唑
itraconazole – n. 伊曲康唑
voriconazole – n. 伏立康唑 bistriazole antimycotic drug – 双三唑抗真菌药
ergosterol – n. 麦角固醇
blastomycosis – n. 芽生菌病
nonmeningeal – a. 非脑膜(炎)的
histoplasmosis – n. 组织胞浆菌病
aspergillosis – n. 曲霉菌病 Scedosporium apiospermum – 尖端赛多孢子菌 Fusarium – n. 镰刀菌
glyburide – n. 格列本
tolbutamide – n. 甲苯磺丁脲
glipizide – n. 格列吡嗪
sulfonylureas – n. 磺脲类
tacrolimus – n. 他克莫司
sirolimus – n. 西罗莫司
torsades de pointes – n. 扭转性室速
Test 1. Silver sulfadiazine is prescribed for a client with a burn injury. Which laboratory finding requires the need for follow-up by the nurse?
A. Glucose level of 99 mg/dL (5.65 mmol/L)
B. Magnesium level of 1.5 mEq/L (0.75 mmol/L)
C. Platelet level of 300,000 mm3 (300 × 109/L)
D. White blood cell count of 3000 mm3 (3.0 × 109/L)
2. Sirolimus (Rapamune) is prescribed to a post-renal transplantation client. Upon the review of the chart, the nurse expects which of the following laboratory results?
A. Elevated serum potassium.
B. Decreased cholesterol level.
C. Elevated platelet count.
D. Elevated triglyceride level.
本期ISPN Review答案: 1. D. White blood cell count of 3000 mm3 (3.0 × 109/L)
Silver sulfadiazine is used for the treatment of burn injuries. Adverse effects of this medication include rash and itching, blue-green or gray skin discoloration, leukopenia, and interstitial nephritis. The nurse should monitor a complete blood count, particularly the white blood cells, frequently for the client taking this medication. If leukopenia develops, the health care provider is notified and the medication is usually discontinued. The white blood cell count noted in option 4 is indicative of leukopenia. The other laboratory values are not specific to this medication, and are also within normal limits.
2. D. Elevated triglyceride level.
Sirolimus (Rapamune) raises cholesterol and triglyceride levels. This medication also causes a decrease in potassium and platelet count.