Article: MSIR

MSIR® is a brand name of oral morphine sulfate currently manufactured by Purdue Pharma. MSIR stands for "Morphine Sulfate Instant Release". It is pronouced "em-es-eye-ar." Roxanol® is a brand name of a concentrated oral morphine solution manufactured by Elan Pharmaceuticals. These drugs are often prescribed for patients with chronic pain (e.g., from terminal cancer) who are already taking extended-release formulations of morphine or other opioids, such as Kadian or MS Contin, but require a rescue dose for breakthrough pain. MSIR is available in 15mg and 30mg tablets, and as a concentrated solution in various strengths. Roxanol is available in several formulations, the most common of which is a 20mg per mL morphine solution. As with all drugs containing morphine in the United States, MSIR and Roxanol are classified as Schedule II controlled substances. Morphine solution may be swallowed, or alternatively, it can be introduced in the buccal space for patients who have difficulty swallowing or who may have nausea.

MSIR, Roxanol®, and other highly-concentrated morphine solutions have been recently scrutinized by Food and Drug Administration (FDA) and other medical organizations due to the high potential for accidental overdose from incorrect dosing. For example, a teaspoon (5 mL) of Roxanol contains 100mg of morphine, which, in a non-opioid tolerant patient, would result in severe respiratory depression and possibly death. Prescription errors are not uncommon with MSIR and Roxanol, because doctors and pharmacists have mistakenly misread milligrams (a unit of strength/weight) as milliliters (a unit of volume/quantity). For instance, prescriptions have been written for "Roxanol solution 20mg/mL, take 10-20 mg every four hours," and have been erroneously filled with the directions to take 10-20 mL every four hours instead. In the latter instance, the patient would have received 200-400mg of morphine instead of the intended 10-20mg, a 20-fold difference. The Institute for Safe Medication Practices, the FDA and the USP have impressed the need to clarify such prescriptions to eliminate errors. At least one manufacturer (Elan) has suggested that written prescriptions for Roxanol and other concentrated morphine solutions should contain both the quantity and strength in the directions. In the example above, the recommended prescription would read "Roxanol solution 20mg/mL, take 10-20mg (1/2 - 1 mL) every four hours," with the aim to eliminate any confusion regarding the intended dose. There are contrary views, however; some believe that including both the quantity and strength side-by-side could lead to even more errors (see article from Arkansas Pharmacy Board below). The foregoing underscores the need for vigilance by pharmacists and doctors in any event to avoid potentially deadly mistakes.