A primary care trial has shown that a commonly used prescription drug is safe and effective to treat irritable bowel syndrome (IBS).
Researchers from the Universities of Leeds, Southampton and Bristol carried out a controlled trial of the drug amitriptyline, a prescription drug used widely in primary care.
Patients using the drug were almost twice as likely to report an overall improvement in IBS symptoms compared to those taking a placebo.
The findings are published in The Lancet, and the researchers recommend that GPs support their patients with IBS to use amitriptyline to manage their symptoms.
Amitriptyline, which belongs to a group of medications called tricyclics, was initially prescribed to treat depression, although this is no longer the case as more effective treatments are now available. It is now commonly used in low doses to alleviate chronic nerve and back pain, and to prevent migraines. The drug has been shown to have possible benefits for IBS patients in hospital clinic settings. This trial is the first to examine the effectiveness and safety of using amitriptyline within a primary care setting.
One in 20 people suffer from IBS worldwide, and most patients are treated and managed within primary care. Patients with IBS experience abdominal pain and changes to bowel movements. There is currently no cure, and the condition can significantly impact quality of life.
The researchers recruited 55 general practice surgeries to the ATLANTIS trial from three regions of the UK, including West Yorkshire, Wessex and the West of England. In total, 463 people took part, with half of the participants being randomly assigned amitriptyline, whilst the remaining half were given placebo tablets. With the support of a patient dose document designed by the researchers specifically for this trial, patients controlled how many tablets they took based on their needs. Patients could increase or decrease their medication based on the symptoms and side effects they experienced.
Patients assigned the amitriptyline reported an increased improvement in symptom scores after six months compared to those taking the placebo. Those taking medication were twice as likely to report an overall improvement in IBS symptoms, and amitriptyline was shown to perform better across a wide range of IBS symptoms than the placebo.
In addition, the researchers noted that anxiety and depression scores were not altered in patients taking the medication, suggesting that the benefits of the drug were via the gut and not because of any side effect related to its previous use as an antidepressant.
The scientists reported no safety concerns and only mild side effects, such as dry mouth in the morning when taking amitriptyline.
Although NICE currently suggests GPs should consider a low dose of triglyceride medication for the treatment of IBS, the evidence of any benefits for IBS patients has yet to be determined. As a result of this study, researchers recommend that primary care support IBS patients with amitriptyline and have made the dose adjustment information available for clinicians and patients in primary care.
Co-chief investigator Professor Hazel Everitt, from the University of Southampton, said: ‘Prior to ATLANTIS, GPs haven’t often prescribed amitriptyline for IBS as the research evidence was uncertain, but our new research provides good evidence of benefit.’
Co-chief investigator Professor Alexander Ford, from the University of Leeds, added: ‘Amitriptyline is an effective treatment for IBS and is safe and well tolerated. This new rigorously conducted research indicates that general practitioners should support patients in primary care to try low-dose amitriptyline if their IBS symptoms haven’t improved with recommended first-line treatments.’