Metronidazole
2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethanol
抗菌劑(系統性)—
厭氧菌感染 : 口服，每公斤體重7.5mg，一次最高達1g，每六小時一次，為時7天。
幽門螺旋桿菌相關之十二指腸潰瘍(治療輔助) : 口服，500mg，一天三次，與Bismuth Subsalicylate及其它口服抗生素如Ampicillin或Amoxicillin併服，為時一至二週。
抗原蟲劑 —
阿米巴病 : 口服，500-700mg，一天三次，為時5-7天。
滴蟲病 : 口服，2g，以單劑量投與，或1g，一天二次，為時一天;或250mg，一天三次， 為時7天。
驅蟲劑(系統性)—
龍絲蟲病(Dracunculiasis) : 口服，250mg，一天三次，為時10天。
一般成人處方限量 : 抗菌(系統性) : 每天最高不可超過4g。 一般孩童劑量:
抗菌劑(系統性)：
厭氧菌感染 : 口服，每公斤體重7.5mg，每六小時一次，或每公斤體重10mg，每8小時I次。
抗原蟲劑：
阿米巴病 : 口服，每公斤體重11.6-16.7mg，一天三次，為時10天。
滴蟲病 : 口服，每公斤體重5mg，一天三次，為時7天。
驅蟲劑(系統性) ：
龍絲蟲病(Dracunculiasis) : 口服，每公斤體重8.3mg，一次最高達250mg，一天三次， 為時10天。
Absorption
Oral metronidazole is well absorbed; topical application is less complete and more prolonged. Following administration, T max is 1 to 2 h, and C max is 25 mg/mL. Oral bioavailability is not affected by food, but peak serum levels will be delayed to 2 h.
Distribution
Metronidazole appears in cerebrospinal fluid, saliva, and breast milk in concentrations similar to those found in plasma. Less than 20% is protein bound.
Metabolism
Metabolites are 2–hydroxymethyl and acidic metabolite.
Elimination
Routes of elimination are via urine (60% to 80%) and feces (6% to 15%). Renal Cl is approximately 10 mL/min per 1.73 m 2 . The t ½ is 8 h in healthy adults, and the hydroxy-metabolite t ½ is 15 h.
Special Populations
Hepatic Function Impairment
Patients with hepatic function impairment metabolized metronidazole slower; accumulation of drug may occur. Cautiously administer doses below the usual recommended dose.
Elderly
Because the pharmacokinetics of metronidazole may be altered in the elderly, monitoring of serum levels may be necessary to adjust the dosage accordingly.
Anticoagulants
Anticoagulant effect may be increased.
Barbiturates, phenytoin
Therapeutic failure of metronidazole may occur.
Cimetidine
May prolong the t ½ and decrease plasma Cl of metronidazole.
Disulfiram
Concurrent use may result in acute psychosis or confusional state. Do not give metronidazole to patients who have taken disulfiram within last 2 wk.
Ethanol
Disulfiram-like reaction including flushing, palpitations, tachycardia, nausea, and vomiting may occur with concurrent use.
Lithium
Plasma levels may be elevated by metronidazole, increasing the risk of lithium toxicity.
3. 患有腦、脊髓疾病之患者。（會顯現出中樞神經系症狀）
4. 懷孕三個月之婦女。
1. 有嚴重肝病之患者。
2. 較易患水腫病者或服用副腎皮質類固醇之患者。
3. 有血液惡病質病歷之患者，治療前後應注意測量其白血球數量。
