Metronidazole Flashcards
What is metronidazole?
nitroimidazole used to treat amebiasis, vaginitis, trchomonas infections, giardiasis, anaerobic bacteria and trponemal infections.
What is metronidazole indicated for?
anaerobic infections (incl. dental) intestinal and extraintestinal amoebiasis, urogenital trichomiasis, giardiasis, HELICOBACTER PYLORI ERADICATION surgical prophylaxis
What class of drugs does metronidazole belong to?
Other antibiotics and antiinfectives
antiprotozoal agents
radiation sensitising agents
What are other compounds which belong to the same class as metronidazole?
niazoxanide ornidazole clindamycin trimethoprim, sulfamethoxazole, vancomycin
What is the role of therapy of metronidazole?
H. pylori eradication (for penicillin allergy?)
What is the dose of metronidazole given to H pylori infection?
Oral: 400mg q8h
What is the mechanism of action of metronidazole?
Prodrug. Unionised form is selective for anaerobic bacteria due to their ability to intracellularly reduce metronidazole into its active form.
Reduced/active form covalently binds to DNA disrupts helical strcutre and inhibits bacterial nucleic acid synthesis, resulting in bacterial cell death
What are the main PK/PD parameters associated with metronidazole?
Well absorbed (~80%)
<20% bound to plasma proteins
hepatically metabolised
half lives of 6-8 hours
What are the precautions associated with metronidazole use?
history of blood disorders
neurotoxicity and blood disorders are more likely with high dose/prolonged treatment
disulfiram like reaction with alcohol
What are the adverse effects associated with metronidazole?
GI disturbances (nausea and vomiting) taste disturbances furred tongue oral mucositis anorexia
less common: QT interval prolongation
What are the interactions with metronidazole use?
Disulfiram like reaction when given with alcohol
Increases plasma concentration of busulfan- increased risk of toxicity
enhances anticoagulant effect of coumarins
psychotic reaction reported with disulfiram
inhibits metabolism of fluorouracil
increases risks of Li toxicitiy
Metabolism of metronidazole accelerated by phenobarbital
Inhibits metabolism of phenytoin
What are the alarm bells associated with metronidazole use?
Monitor if treatment >10 days or if patient exhibits disulfiram like reaction with alcohol.
What are the contraindications with metronidazole use?
active organic disease of the CNS
