Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Dangerous interaction between the antibiotic ciprofloxacin and the muscle relaxant tizanidine

16.12.2004


Researchers from Finland have found that the antibiotic ciprofloxacin (brand names Ciproxin, Ciprofloxacin etc.) greatly increases the concentrations of tizanidine (Sirdalud, Zanaflex) in blood. Concomitant use of ciprofloxacin and tizanidine results in severe and prolonged decrease in blood pressure and greatly enhances central nervous system effects.



This previously unrecognised interaction can be dangerous, particularly in elderly patients, and the concomitant use of the two agents must be avoided. Tizanidine is widely used for treatment of musculoskeletal pain associated with increased muscle tension or chronic spasticity.

The concentrations of tizanidine in blood were increased on average 10-fold by ciprofloxacin in a carefully controlled study in healthy volunteer subjects. The volunteers ingested the usual 500-mg dose of ciprofloxacin (or placebo) twice daily for 3 days, and then a single 4-mg dose of tizanidine. The interaction was observed in each of the ten subjects; the greatest increase in tizanidine concentration by ciprofloxacin was 24-fold.


Ciprofloxacin enhanced greatly also the effects of tizanidine. In particular, the decrease in systolic (“upper”) blood pressure, to the level of 90-mm Hg or even less, was an alarming finding. Such hypotension can be dangerous, eg in elderly subjects and in patients who have heart problems. Also the central nervous system effects of tizanidine were greatly enhanced by ciprofloxacin: all ten subjects were somnolent and dizzy for about 3 hours after tizanidine intake.

Both tizanidine and ciprofloxacin are widely used drugs in many countries. E.g. in Finland (population 5 200 000) about 136 000 patients used tizanidine and about 60 000 patients used ciprofloxacin during the year 2003. Therefore, it is likely that ciprofloxacin and tizanidine can be coadministrered, if the risk of the interaction is not recognised by clinicians.

The interaction results from inhibition of the liver metabolism of tizanidine by ciprofloxacin. The same mechanism causes a serious interaction also between the antidepressant fluvoxamine and tizanidine, which was uncovered earlier this year. Further studies are being carried out to study whether there are other unrecognised interactions between tizanidine and other drugs.

The study was conducted at the Department of Clinical Pharmacology, University of Helsinki, by an independent group of researchers led by Professor Pertti J Neuvonen, MD, PhD, and Dr. Janne T Backman, MD, PhD. The study was published in the December issue of Clinical Pharmacology & Therapeutics, the leading scientific journal within the clinical pharmacology and therapeutics area.

Paivi Lehtinen | alfa
Further information:
http://www.helsinki.fi

More articles from Life Sciences:

nachricht Synthetic nanoparticles achieve the complexity of protein molecules
24.01.2017 | Carnegie Mellon University

nachricht Immune Defense Without Collateral Damage
24.01.2017 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Arctic melt ponds form when meltwater clogs ice pores

24.01.2017 | Earth Sciences

Synthetic nanoparticles achieve the complexity of protein molecules

24.01.2017 | Life Sciences

PPPL physicist uncovers clues to mechanism behind magnetic reconnection

24.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>