A nitroimidazole antibiotic used particularly for;
Anaerobic bacteria &
Protozoa
Its an antimicrobial drug which is highly active against;
Anaerobic bacteria
Some protozoa
Amoeba
Thus metronidazole is an;
Antibiotic drug
Ameobicide
Antiprotozoal
Its common trade name is Fragyl in USA & Uganda
Tinidazole is similar to metronidazole but with a long duration of action
2. A nitroimidazole antibiotic used particularly for;
Anaerobic bacteria &
Protozoa
Its an antimicrobial drug which is highly active
against;
Anaerobic bacteria
Some protozoa
Amoeba
3. Thus metronidazole is an;
Antibiotic drug
Ameobicide
Antiprotozoal
Its common trade name is Fragyl in USA & Uganda
Tinidazole is similar to metronidazole but with a
long duration of action
4. Anti-bacterial ,anti-protozoal & amoebic activity of
metronidazole
This drug is kills;
1. Anaerobic bacteria like;
Bacteroides fragilis spp
Fusobacterium spp
Clostridium spp; c. tetani ,c. difficile ,
c. perfringens
5. Peptococcus spp
Peptostreptococcus spp
Prevotella spp etc
2. Protozoa like giardia lamblia which coz giardiasis
3. Amoeba like entamoeba histolytica which can coz
bacillary dysentery, hepatic abscess (amoebema)
6. Pharmacodynamics
Mechanism of action
Metro is selectively absorbed by anaerobic
bacteria, sensitive protozoa & amoeba
Within these micro-organisms fragyl is
converted to a toxic form that damages the
DNA of the microorganisms
7. Pharmacokinetics
Its available in form of;
Tabs
Syrups
IV solutions
Topical application gel
Rectal preparations (suppositories)
8. Metronidazole shld always be taken;
With a large glass of water
With or after food
When given orally its rapidly & completely
absorbed frm gut
Its distributed rapidly throughout all tissues & body
fluids + CSF
9. Some is metabolised & most is excreted in urine
Plasma half life is about 7 hrs
10. Dosage
Adult:
PO; (varies depending on disease)
200-400 mg 2-3 times /d (common)
800mg start then 400mg 3 times/d
250-500mgs 2-3 times/d
2g start
IV ;500mg 2-3 times /d
15. 2. Surgical prophylaxis 2 hrs before surgery in high
risk procedures like colorectal surgery or
appendectomies
3. Surgical & gynecological septicaemia due to
colonic anaerobes like bacteroides fragilis
4. Amoebic dysentery due to entamoeba histolytica
16. 5. Tx of symptomatic bacterial vaginosis due to
overgrowth of gardnerella spp & co-infective
anaerobes (mobiluncus, bacteroides)
6. Pseudomembranous colitis due to Clostridium
difficile
7. Tx of peptic ulcer disease by eradicating
Helicobacter pylori in a triple therapy regimen
17. 8.Established cases of tetanus in combination with
diazepam & tetanus immunoglobulin
9.Oral infections like acute necrotizing ulcerative
gingivitis & other dental infections
10.Tx of pelvic inflammatory disease in combination
with other antibiotics like ofloxacin, levofloxacin,
doxycycline or ceftriaxone
18. 11.Tx of septic leg ulcers & pressure sores
12. Treatment of giardiasis which is a protozoa
infection leading to non bloody diarrhoea & GI Sx
13. Crohn's disease with colonic or perianal
involvement in combination with ciprofloxacin
14. Tx of trichomonal vaginitis due to protozoa
trichomonas vaginalis
19. Indications for topical metronidazole
1. Treatment of rosacea
2. Treatment of malodorous fungating wounds
3. Killing of malodorous producing anaerobic
bacteria in fungating tumors like malignant
melanomas
21. Its has few S/Es
1. Minor Gl disturbances like
Metallic & bitter mouth taste
Nausea & vomiting
Anorexia
Diarrhoea
Furred tongue
Oral mucositis
2. Thrombophlebitis after IV drug
22. Other very rare S/Es
1. Blood disorders like thrombocytopenia,
neutropenia, pancytopenia etc
2. Hypersensitivity reactions like;
Rash
Pruritus
Fevers
Flushing of the skin
25. Contraindications
1. First trimester of pregnancy
2. Relatively contraindicated in pts with hepatic
impairment & hepatic encephalopathy
3. Concurrent intake of alcohol with metronidazole
bcoz Fragyl inhibits alcohol metabolism leading to
flushing, DIB, tachycardia, N&V etc
4. Acute porphyria