Heart drugs combination can cause muscle damage

U.S. health officials warned the public on Friday about the risk of a rare type of muscle injury seen when the cholesterol drug simvastatin is combined with the anti-arrhythmia medicine amiodarone.

The Food and Drug Administration said it continued to receive reports of rhabdomyolysis, a type of muscle injury that can lead to kidney failure or death, despite a 2002 warning about combining the drugs.

Simvastatin is an ingredient in Merck & Co's Zocor and Abbott Laboratories Inc's Simcor, and is sold generically. It also is one of two components in Merck and Schering-Plough Corp's Vytorin.

Amiodarone is an ingredient in Wyeth's Cordarone and is also sold generically. Upsher-Smith sells a version under the name Pacerone. The drug is used to control a life-threatening type of abnormal heart beat.

All drugs in the statin class of medicines, which include simvastatin, Pfizer Inc's Lipitor and others, carry a potential risk of rhabdomyolysis.

But compared with other statins, the risk is "more pronounced" when simvastatin is given with amiodarone, the FDA said. The risk increased with simvastatin doses greater than 20 milligrams per day.

"Prescribers should be aware of the increased risk of rhabdomyolysis when simvastatin is prescribed with amiodarone, and they should avoid doses of simvastatin greater than 20 mg per day in patients taking amiodarone," the FDA said in a notice on its website.

The FDA has confirmed 52 U.S. reports of rhabdomyolysis associated with use of amiodarone and simvastatin since the 2002 warning, agency spokeswoman Susan Cruzan said. During the same period, there were six cases linked with use of other statins and amiodarone, she said.

Patients should contact a doctor immediately if they develop unexplained muscle cramps, pain, tenderness, stiffness or spasms, the FDA said.

The muscle injury risk has been "very clearly stated" on Zocor's label since 2002, Merck spokesman Ron Rogers said.

Schering-Plough spokesman Lee Davies also said the risk was noted in Vytorin's prescribing instructions for years, and Abbott spokeswoman Elizabeth Hoff said the "prescribing information for Simcor already contains this information."

Wyeth noted a possible interaction specifically with simvastatin on Cordarone's label about six months ago, company spokesman Doug Petkus said. Earlier information mentioned a risk when combining Cordarone with Lipitor and implied it would apply to other statins, he said.

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Muscles strength not reduced by little stretching

While some research has raised the question of whether pre-workout stretching hinders muscle performance, a new study suggests that a few minutes of stretching may not sap the average exerciser's muscle strength.

Stretching is part of many active people's pre-exercise routine. But some recent studies have been pointing to potentially negative effects on athletic performance.

In some studies, though not all, stretching right before a workout has been found to decrease both sprint speed and jump height. There's also evidence that stretching temporarily reduces muscle strength.

However, one question has been whether such effects would be seen after the short bouts of stretching that a typical exerciser or weekend athlete might perform.

The new study, published in the journal Medicine & Science in Sports & Exercise, looked at just such a "practical" stretching regimen.

Researchers measured calf-muscle strength in 13 moderately active men and women under four different conditions: after no stretching, and before and after 2, 4 or 8 minutes of calf-muscle stretching.

They found that stretching did not diminish the participants' muscle strength compared with the no-stretching condition. It did, however, temporarily improve the range of motion in the ankle joint.

The findings suggest that "a few minutes of static stretching of the calf muscles before exercise is unlikely to diminish muscle strength," senior researcher Dr. Joel T. Cramer, of the University of Oklahoma in Norman, told Reuters Health.

Past studies, he noted, have shown that longer, less practical stretching regimens may in fact dampen calf muscle strength for a short time. "However," Cramer said, "most exercisers do not continuously stretch their calves for 10, 20 or 30 minutes."

It is possible that other muscle groups respond differently to stretching than the calf muscles do, according to Cramer. For instance, the quadriceps and hamstrings -- muscles in the front and back of the thighs, respectively -- may be more susceptible to the strength-sapping effects of stretching.

More studies are needed to answer that question, Cramer said.

Another limitation of the current study is that it included only moderately active people -- not athletes, who might be more affected by small changes in muscle strength or power brought on by pre-competition stretching.

None of this means that stretching is not useful to active people. As demonstrated in the current study, stretching can improve joint range of motion in the short term. And some studies suggest that over the long term, a regular stretching regimen can help build muscle strength.

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