The effect of smoking on the bioavailability of metronidazole in plasma and saliva.
BACKGROUND
Cigarette smoking is considered to be a major risk factor for periodontal disease, and the antimicrobial agent metronidazole is commonly used for treatment of periodontitis. The authors evaluated the effect of cigarette smoking on the bioavailability of metronidazole in plasma and saliva.


METHODS
Thirteen smokers and 13 nonsmokers received a single oral dose of 750 milligrams of metronidazole. Study personnel collected blood and saliva samples at baseline and at 0.5, 1, 1.5, 2, 4, 6, 8, 12, 24 and 48 hours after metronidazole administration. The authors quantified plasmatic and salivary metronidazole concentrations by means of high-performance liquid chromatography, and they determined the pharmacokinetic parameters and analyzed them statistically by using the Mann-Whitney test and nonpaired t test (α = 5 percent).


RESULTS
The authors detected a significant reduction in plasmatic metronidazole concentrations in smokers at 1 hour, 1.5 hours and 2 hours compared with nonsmokers (P < .05). They also found a significant reduction in the maximum concentration in plasma in smokers as compared with that of nonsmokers (P < .05). The authors observed no statistically significant differences in the salivary concentration or pharmacokinetics between the two groups, however (P > .05).


CONCLUSIONS
Cigarette smoking interfered with the bioavailability of metronidazole in plasma but not in saliva.  Practice Implications.  The clinical significance of these findings needs to be investigated further to verify the effectiveness of metronidazole in smokers.
Department of Oral Pathology, São Leopoldo Mandic Institute and Research Center, Campinas, São Paulo, Brazil.
Victor Angelo
VA
Montalli
Cristiane de Cassia
Cde C
Bergamaschi
Juliana Cama
JC
Ramacciato
Fabiana Pinchetti
FP
Nolasco
Francisco Carlos
FC
Groppo
Rui Barbosa de
RB
Brito
Daniel A
DA
Haas
Rogerio Heladio Lopes
RH
Motta
D000293:Adolescent; D000890:Anti-Infective Agents / Q000097:blood* / Q000493:pharmacokinetics; D019540:Area Under Curve; D001682:Biological Availability; D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D002851:Chromatography, High Pressure Liquid; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008795:Metronidazole / Q000097:blood* / Q000493:pharmacokinetics; D012463:Saliva / Q000378:metabolism*; D012907:Smoking / Q000378:metabolism*; D055815:Young Adult
D000890:Anti-Infective Agents; D008795:Metronidazole