Metondazole

Systemic Metronidazole i n Periodontal Therapy

Usama M. madanyProfessor, Department of Oral Medicine

Periodontology, Diagnosis and Oral Radiology, Faculty of Dental Medicine , Al-Azhar University

- Commonly used antibiotics in periodontal therapy :

Tetrayclines (doxycycline) MetronidazoleClindamycin Penicillins (amoxicillin)Erythromycins (azithromycin, clarithromycin)Ciprofloxacin

The microbial etiology of inflammatory periodontal diseases provides the rationale for the local and systemic use of different antibiotics in periodontal therapy.

-Systemic antibiotic therapy in periodontics should be reserved to the following:

A. Prophylaxis for patients with medical problems requiring antibiotic coverage.

B. Patients with systemic manifestations associated with

acute periodontal infections (ANUG and acute periodontal abscess) .

C. As an adjunct to surgical and non surgical periodontal therapy.

D. Patients who undergo continued periodontal breakdown in spite of thorough debridement and excellent home care .

Metronidazole

Pharmacology and spectrum:

-It is a nitroimidazole compound mainly active against protozoal infections.

-It is very effective in low reduction potential areas, and bactericidal to anaerobes through inhibition of DNA synthesis.

-It can readily attain effective antibacterial concentration in gingival tissue, saliva and crevicular fluid.

-It is effective against the microorganism strongly associated with and implicated in pathogenesis of periodontal disease.

% Absorption after Peak serum level Serum half-life

Antibiotic oral adminestration (µg/ml) (hours)

Metronidazole 90 20-25 6-14

Tetracyclines 93 2- 4 18

(Doxycyline)

Clindamycin 90 5 2.4

Penicillins 75 5- 8 1.2

(Amoxicillin)

Ciprofloxacine 70 1.5 4

Erythromycines 37-50 0.4-3 5-12

Selected pharmacological features of common antibiotics in use for periodontics

•metronidazole

metronidazole

metronidazole

AaP. intermedia

sprichetes

Anaerobes

Metronidazole

Spirochetes

P. gingivalis

P. intermedia

A.actinomycetemcomitansHydroxy metaolites of nitroimidazole

+ other antibiotics

tissues

Clinical use of systemic metronidazole:

If to be used, metronidazole should not be administered as monotherapy.

Alone

1- Treatment of ANUG 2- Treatment of periodontitis

250-500 mg/ tid/ 3-5 days 750-1000 mg /day for 7-14 days*

- growth of anaerobic bacteria.

- histopathological and Clinical

signs of periodontitis.

- the need for surgery.

-Recommended doses :

250 mg/ tid/ 7 days (Greenstien, 1993).

500 mg/ tid/ 8 days (Slots and Ting,

2002)

Loesche 1992; Nieminen et al.1996; Soder 1999.

Combined with other antibiotics -Complexity of periodontal pathogens in dental biofilm (dental plaque).-Considerable variation of sensitivity of these bacteria to different antibiotics.Treatment of periodontitis:

1- Metronidazole + amoxiciilin 250 mg/ tid/ 8 days of each drug. 2- Metronidazole 250 mg + amoxycillin-clavulanate potassium (augmentin) 375 mg / tid/ 8 days.3- Metronidazole + ciprofloxacin 500 mg/ bid/ 8 days of each drug.

-These regimens resulted in improved clinical status and suppression and/or elimination of Aa and Pg in aggressive and recurrent forms of periodontitis ( Slots and Ting 2002, AAP position paper 2004).

Adsverse reactios and side effects:

-Nausia/vomiting

-Unpleasant (metallic) taste.

-Pregnancy: Possible risk of teratogenicity.

Drug Interactions*:

1-Metronidazole metabolism of warfarin prolonged prothrombin time bleeding tendency (definite action).

2-Metronidazole + Ethanol disulfiram-like reaction:

nausia, vomiting, severe cramps, flushing, sweating, hypotension, palpitation and headache (probable action).

*Yagiela, 1999, Horn et al.2004

3-Metronidazole metabolism of oral hypoglycemic drugs Hypoglycemia (probable) .

5-Metronidazole may inhibit the action of estrogen components of oral contraceptives unexpected pregnancies ( Hersh 1999).

6-Barbiturates effectiveness of metronidazole (probable).

Precautions on prescription

1-Metronidazole should be avoided in patients undergoing warfarin therapy.

2-Alcohol containing products should be avoided during metronidazole therapy and for at least one day after therapy is discontinued.

3-Metronidazole is better to be avoided for diabetics on oral hypoglycemic drug.

4-It should be avoided during pregnancy especially in the first trimester, and also for females on oral contraceptives.

5-In patients with impairment of liver functions, metronidazole is better to be avoided or its dose to be decreased.

6-Dose for children should by properly adjusted according to body weight (7.5 mg/kg 8 hourly).