USFoodandDrugAdmin asked:
A report from the Institute for Safe Medication Practices lists several reasons for the serious and sometime fatal overdoses that have occurred when methadone is used to treat moderate to severe chronic pain. ISMP points out that methadone differs from other opioids in a number of ways. For example, methadone remains in the body long after its analgesic effect has worn off. Also, a patient may not experience the full analgesic effect of methadone until 3-5 days of use, so it must be titrated more slowly than other opioids. And a high degree of tolerance to other opioids does not eliminate the possibility of methadone overdose. ISMP cites two fatalities and a near fatality from prescribing too large a methadone dose for patients who had previously taken high daily doses of Oxycontin or Vicodin. Also, if a patient on methadone stops taking the drug for three consecutive days, the patient may lose tolerance for methadone and be at risk for an overdose if the usual dose is resumed. Errors have also been reported because of confusion between methadone and other drugs with “look alike” names. In one report, a 17-year old patient with a traumatic brain injury received 25 mg of methadone BID instead of methylphenidate and suffered respiratory arrest. ISMP also points out that errors can occur because of confusion between mL and mg doses. In one case, a patient had been taking 13 mg/day of methadone, which was prepared in the community pharmacy using a 1 mg/mL methadone …
carisoprodol
