Tongxinluo, in capsule form, is a traditional Chinese medicine which consists of herbs and insects. Traditionally it has been thought to have clinical benefits for patients with angina, including the reduction of the occurrence of acute myocardial infarction (AMI), and complications of some types of heart surgery. Some studies also suggest a possible benefit in reducing the frequency and severity of angina attacks and improving symptoms. However, none of these individual studies have been reviewed systematically.
The review authors systematically reviewed evidence from 18 randomised controlled trials for the benefit of tongxinluo with or without other treatments, including routine care or placebo, for patients with unstable angina. All the trials were conducted in China. The total number of participants was 1413, ranging in age from 25 to 88 years. Most studies randomised patients to receive tongxinluo with conventional medication or conventional medications alone.
There was some evidence from seven studies that tongxinluo improved the electrocardiogram (ECG) changes indicating ischaemia and reduced the number of people with no improvement or worsening of ECG (six studies). Some improvement in angina symptoms (10 studies) and reduced numbers of people showing no improvement or worsening of symptoms were apparent with tongxinluo. Tongxinluo appeared to be as effective as isosorbide mononitrate in three studies. A few cases of slight gastrointestinal discomfort were reported after giving tongxinluo in seven studies and three cases of breaking of tiny blood vessels under the skin (ecchymosis) in one study.
The evidence suggested possible benefits relating to a range of outcomes among patients with unstable angina but all the studies were of poor quality and neither blinding nor allocation concealment were used. This makes it impossible to reach firm conclusions about the benefit of this treatment. Large, high quality, randomised controlled trials are needed to confirm the possible benefit of tongxinluo for unstable angina and to suggest appropriate future use of this herbal medicine.