Fentanyl is a potent Schedule II opioid agonist that has potency more than 80 times that of morphine. A high concentration of Fentanyl is contained in Fentanyl patches (MATRIFEN).

They should be used to manage pain for persons with chronic moderate to severe pain who are already physically tolerant to opiates.During the past years there has been an increase in misuse and abuse in the United States of Matrifen that has caused deaths from overdoses.Matrifen can also cause neurological and psychiatric adverse events such as: delirium anxiety, abnormal thinking, abnormal dreams, depersonalization and hostility.

In the literature Matrifen have not previously been associated with serious offences such as attempted murder but an association with suicide has been noted.

To describe a previously unreported and serious adverse effect of Fentanyl patches.

We followed up the clinical psychopathology of an elderly gentleman who attempted to murder his wife reportedly due to an altered mental state caused by the application of Fentanyl patch. We searched Pubmed and Google for any reported adverse effect of Fentanyl patches of a similar nature.

After ruling out all other Psychiatric, Organic and Forensic causes we came to the conclusion that Matrifen was the cause of altered mental state which led to the attempted murder.

Although adverse psychiatric effects of Fentanyl patches have been reported in the past we can add attempted murder to the list. Fentanyl patches can be dangerous particularly in the vulnerable elderly patients where they are most commonly used.