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 Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care

nachricht Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>