Core pharmacology

Class Group

ANTIBIOTIC:
NITROIMIDAZOLE

Legacy Cicm Level

Level 3

Introduction

Nitroimidazole

Mechanism of action

Converted to active form or nitroso free radical by
obligate anaerobes. Inhibits DNA synthesis. Causes DNA degradation

Antimicrobial Spectrum

Active against anaerobes (including clostridium, N.Gonorrhoea, N.Menigitidis, Bacterioides and Fusobacterium) and protozoa
(trichomonas, Giardia)

Resistance Mechanism

reduced rate of uptake, by efflux or by reducing the rate of metronidazole reductive activation
increased DNA repair efficiency

Adverse Effects Toxicity

GIT– abdominal pain, N/V/D,
jaundice, pancreatitis
HAEM- leukopenia
CVS– T wave flattening, QT
prolongation
CNS– ataxia, seizures, insomnia, paraesthesia
HYPERSENSITIVITY– rash
OTHER– metallic taste

Absorption

50% PO BA
75% Rectal BA

Distribution

Widely distributed to all tissues

Protein binding

10% PB

Volume of distribution

Vd 0.75 L/kg

Metabolism

Hepatic Oxidation and glucuronidation

Excretion

Renal excretion 60% unchanged

Half-life

T1/2 = 6-10hrs
Renal dose adjustment not required