Abstract
Dear Editor:
I appreciate the authors of the case report entitled “A Case of Esophagogastric Junction Cancer Treated with Pain Control by Administering Methadone Tablets Through a Gastrostomy” for their meticulous description of the tube administration safety of a methadone suspension. 1 The authors have provided objective evidence of therapeutic levels of methadone as well as its safety and efficacy following its administration as a simple suspension of the oral tablets.
The authors mention that there have been no previous reports examining the administration of methadone when the oral route becomes unavailable. I would like to draw their attention to a published letter on the use of syrup methadone in a jejunostomy tube (J-tube). 2 The correspondence briefly describes cancer pain management in a patient with carcinoma hypopharynx with a J-tube. Liquid methadone was the only option in the given situation and was used in the j-tube and found to be clinically effective. At the time, there was no published data on the suitability of methadone through a feeding tube. Methadone pharmacokinetics dictate that it is absorbed in the acidic environment of the stomach, and absorption is negligible beyond the pylorus. 3 Despite this theoretical concern, we found that the patient had effective analgesia after switching to methadone for nearly five months. Given that performance of blood levels of methadone cannot be routinely performed, we resorted to clinical response as a surrogate indicator of clinical efficacy. Also, our patient demonstrated no adverse effects during the time that could be attributed to methadone. The dose requirement was a modest 35 mg/day in three divided doses. Therefore, we concluded that liquid methadone could be safely administered through the J-tube.
In developing countries, such as India, a large majority of patients suffer from advanced aerodigestive tract cancers and lose the oral route for medication administration. This necessitates the insertion of feeding tubes, either nasogastric or post-pyloric. Often these patients also suffer from complex cancer-related pain and may need opioid rotation, options for which are painfully few. In this milieu, methadone is not only a cost-effective alternative to fentanyl but is also being recognized as a powerful analgesic in refractory cancer pain management due to its broad spectrum of action. 4
Physicians often prescribe oral medications through feeding tubes without mindfully considering the consequences of the change in the site of absorption of the oral drugs that the patient was receiving. Literature providing guidance for the administration of diverse medications is sparse and constantly evolving. Hence, this case report has brought forth practical information backed by sound scientific proof, which can be used by palliative care physicians worldwide. While we have clinical evidence that liquid methadone is efficacious when administered through a J-tube, formal blood levels of methadone have not been measured. This can be a subject of a future investigation providing tangible proof of post-pyloric methadone absorption and providing information about the dose and duration needed to produce a clinical effect.