In vitro and in vivo synergism between tetracycline and the cardiovascular agent oxyfedrine HCl against common bacterial strains

Kaushiki Mazumdar, Noton Dutta, Kuppusamy Asok Kumar, Sujata Ghosh Dastidar

Research output: Contribution to journalArticle


The cardiovascular drug oxyfedrine HCl revealed noteworthy in vitro antibacterial action against 501 strains of Gram positive and Gram negative bacteria. It also offered significant protection to mice challenged with a mouse-virulent bacterial strain. Prompted by such results, the present study was carried out to ascertain whether this drug could augment the efficiency of an antibiotic when used in combination with it. For this purpose, ten bacterial strains were selected, which were sensitive to oxyfedrine as well as to six antibiotics, like benzyl penicillin, chloramphenicol, ciprofloxacin, erythromycin, streptomycin and tetracycline. Distinct and statistically significant (p<0.01) synergism was observed between oxyfedrine and tetracycline by disc diffusion tests, compared with their individual effects. The fractional inhibitory concentration (FIC) index of this combination, evaluated by checkerboard analysis, was 0.37, which confirmed synergism between the pair. This synergistic drug duo was further dispensed to infected mice. The results of the mouse-protection tests advocated that the combination was significantly synergistic (p<0.0001), according to Student's 't' test. Hence, the capacity of extended antibiotic therapy in several microbial diseases may be improved with the help of this synergistic drug pair, and the study might throw light on newer directions to contest drug-resistant bacterial infections.

Original languageEnglish (US)
Pages (from-to)713-717
Number of pages5
JournalBiological and Pharmaceutical Bulletin
Issue number4
Publication statusPublished - Apr 2005
Externally publishedYes



  • Antimicrobial activity
  • Non-antibiotic
  • Oxyfedrine
  • Synergism
  • Tetracycline

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology, Toxicology and Pharmaceutics(all)

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