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 Even plants can be stressed
03.09.2015 | Max-Planck-Institut für Molekulare Pflanzenphysiologie

nachricht Research team from Münster develops innovative catalytic chemistry process
03.09.2015 | Westfälische Wilhelms-Universität Münster

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fraunhofer ISE Develops Highly Compact Inverter for Uninterruptible Power Supplies

Silicon Carbide Components Enable Efficiency of 98.7 percent

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE have developed a highly compact and efficient inverter for use in uninterruptible power...

Im Focus: How wind sculpted Earth's largest dust deposit

China's Loess Plateau was formed by wind alternately depositing dust or removing dust over the last 2.6 million years, according to a new report from University of Arizona geoscientists. The study is the first to explain how the steep-fronted plateau formed.

China's Loess Plateau was formed by wind alternately depositing dust or removing dust over the last 2.6 million years, according to a new report from...

Im Focus: An engineered surface unsticks sticky water droplets

The leaves of the lotus flower, and other natural surfaces that repel water and dirt, have been the model for many types of engineered liquid-repelling surfaces. As slippery as these surfaces are, however, tiny water droplets still stick to them. Now, Penn State researchers have developed nano/micro-textured, highly slippery surfaces able to outperform these naturally inspired coatings, particularly when the water is a vapor or tiny droplets.

Enhancing the mobility of liquid droplets on rough surfaces could improve condensation heat transfer for power-plant heat exchangers, create more efficient...

Im Focus: Increasingly severe disturbances weaken world's temperate forests

Longer, more severe, and hotter droughts and a myriad of other threats, including diseases and more extensive and severe wildfires, are threatening to transform some of the world's temperate forests, a new study published in Science has found. Without informed management, some forests could convert to shrublands or grasslands within the coming decades.

"While we have been trying to manage for resilience of 20th century conditions, we realize now that we must prepare for transformations and attempt to ease...

Im Focus: OU astrophysicist and collaborators find supermassive black holes in quasar nearest Earth

A University of Oklahoma astrophysicist and his Chinese collaborator have found two supermassive black holes in Markarian 231, the nearest quasar to Earth, using observations from NASA's Hubble Space Telescope.

The discovery of two supermassive black holes--one larger one and a second, smaller one--are evidence of a binary black hole and suggests that supermassive...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Together - Work - Experience

03.09.2015 | Event News

Networking conference in Heidelberg for outstanding mathematicians and computer scientists

20.08.2015 | Event News

Scientists meet in Münster for the world’s largest Chitin und Chitosan Conference

20.08.2015 | Event News

 
Latest News

Lighter with Laser Welding

03.09.2015 | Process Engineering

For 2-D boron, it's all about that base

03.09.2015 | Materials Sciences

Phagraphene, a 'relative' of graphene, discovered

03.09.2015 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>