Old cardiac drug performs new tricks

By Piriya Mahendra, MedWire Reporter

An animal study has shown that the anti-angina drug ranolazine could significantly reduce the number of deaths from carbon monoxide poisoning.

Chris Peers (University of Leeds, UK) and colleagues say that although the findings come from a study in rats, they could have important implications for the development of a protective treatment for people who have been exposed to toxic levels of the gas.

"When patients are admitted to hospital with carbon monoxide poisoning, the main problem doctors face is preventing damage to the body whilst the body slowly removes the chemical," commented Peers in a press statement.

"We've shown that ranolazine can rapidly protect the heart and prevent the kind of cardiac events which threaten patients long after their exposure to the gas."

Carbon monoxide poisoning leads to 1.6 million deaths worldwide each year. The majority of people who have been exposed to the gas develop cardiac arrhythmias, which if left untreated, may lead to fatal cardiac arrest.

Ranolazine, which was approved in 2006 in the USA for the treatment of angina, targets a sodium channel in the heart which also induces irregular heartbeats. Peers et al found that exposure to carbon monoxide increases nitric oxide within myocyte cells and causes this channel to stay open for longer, allowing calcium to build up within cells. This ultimately alters the heart's rhythm.

As reported in the American Journal of Respiratory and Critical Care, treatment with ranolazine in rats reversed this pro-arrhythmic effect and, according to telemetry analysis, also corrected QT variability.

"Whilst the link between arrhythmias and carbon monoxide has been known for over 50 years, this is the first piece of research to explain the underlying process," commented co-author Derek Steele, also from the University of Leeds.

Peers adds that the next step is to replicate the findings in human trials. "As the drug has been clinically approved, roll out of this treatment could begin soon after we have these results."

Hélène Wilson, Research Advisor at the British Heart Foundation, said the current study is a good example of research being used to better understand the underlying causes of abnormal heart rhythms. "In this case it has uncovered the ability of an old drug to perform a new trick," she remarked.

"Carbon monoxide poisoning is tragically common but hopefully these promising results can be replicated in people so that it saves lives in the future."

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