Nitrates (medicines) for achalasia (impaired swallowing)

Achalasia is a condition where the lower part of the oesophagus leading to the stomach is unable to relax normally after swallowing. Food may become stuck there rather than going through into the stomach. Although the cause of achalasia is not known, it is well demonstrated that loss of oesophageal neurons is the underlying problem. Patients may experience dysphagia, regurgitation of food, retrosternal pain and so on. Nitrates are drugs that may relax the muscle and they are used to try to relieve the symptoms. They can be taken either as tablets, or absorbed under the tongue. Nitrates can be used in patients with mild symptoms, where it is not necessary to perform an invasive procedure such as surgery or if the patient is not a suitable candidate for surgery for some other reason. Nitrates can also be used if there is no response to injections of botulinum toxin to relax the muscle of the oesophagus. One other widely used option for the treatment of achalasia is dilation of the oesophagus using endoscopic methods. This review found there is not enough evidence from trials to show if nitrates are an effective treatment to relieve achalasia.

Authors' conclusions: 

From most of the single reports we found, after intake of nitrates (either nitroglycerin or isosorbide dinitrate), there was a fall in lower oesophageal pressure and improvement of radionuclide esophageal emptying compared to the baseline. From the available evidence, we cannot provide any implications for practice. Appropriately designed, parallel group, randomised controlled trials with long term follow-up are needed to determine the effects of nitrates for achalasia.

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Background: 

Achalasia is a disease that impairs oesophageal motility. Although nitrates have been used to treat achalasia for a long time, the effectiveness of nitrates for achalasia is still controversial. Newer therapies have to some extent superceded the use of nitrates for achalasia, but nitrates may still be used in early or mild disease, in patients who are unsuitable for surgery or invasive procedures, or when botulinum injection therapy has failed.

Objectives: 

To quantify short-term and long-term effects of nitrate therapy in participants with achalasia.

Search strategy: 

Trials were identified by searching the Cochrane Controlled Trials Register (Issue 4-2001), MEDLINE (1966-2001), EMBASE (1980-2001), LILACS - Latin American and Caribbean health science literature (1982-2001) and CBM-Chinese Biomedical database(1980-2000). Additionally, all references in the identified trials were checked for further relevant trials. An updated search was run on the Cochrane Library, MEDLINE, and EMBASE in September 2003, October 2004, September 2005 and December 2008.

Selection criteria: 

All randomised controlled trials involving achalasic participants given any type of nitrates were included.

Data collection and analysis: 

Data were extracted by two independent observers.

Main results: 

Two randomised cross-over studies were found, but no results were included. Due to the design of the studies and the method of reporting the results in the original paper it was not possible to extract the necessary information to examine any of the outcomes.

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