Extended-release (orslow-release)formulations of morphine are those whose effect last substantially longer than baremorphine, availing for, e.g., one administration per day. Conversion betweenextended-release and immediate-release (or "regular") morphine is easier than conversion to or from anequianalgesic dose of another opioid with different half-life, with less risk of alteredpharmacodynamics.
Brand names for this formulation of morphine includeAvinza,[1]Kadian,[1]MS Contin,[1]MST Continus,[2][3][4][5]Morphagesic,Zomorph,Filnarine,MXL,[6]Malfin,Contalgin,Dolcontin, andDepoDur.[7][8] MS Contin is atrademark ofPurdue Pharma, and is available in the United States and Australia. In the UK, MS Contin is marketed byNAPP Pharmaceuticals as MST Continus. MS Contin is a DEASchedule II substance in the United States, a Schedule 8 (controlled) drug in Australia and a Schedule 2 CD (Controlled Drug) in the UK.
Avinza is made byKing Pharmaceuticals and Kadian is made by Actavis Pharmaceuticals. Unlike the MS Contin brand and its generic versions, Kadian and Avinza are designed to be 12- to 24-hour release, not 8- to 12-hour. So instead of 2–3 times a day dosing, it can be 1–2 times.
MST Continus[2][3][4] and MXL[6] are registeredcopyright and trademark of Napp Pharmaceuticals and are available in the UK. MXL is a 24-hour release formula designed to be taken once daily. It is available in doses between 30 mg and 200 mg in 30 mg intervals (equating to between 1.25 mg/hour and 8.33 mg/hour). MST Continus is a 12-hour release formula, therefore it is given 2 times per day. It is available in the following doses: 5 mg, 10 mg, 15 mg, 30 mg, 60 mg, 100 mg and 200 mg tablets (equating to between 0.416 mg/hour and 16.67 mg/hour).
For constant pain, the relieving effect of extended-release morphine given once (for Kadian[9]) or twice (for MS Contin[9]) every 24 hours is roughly the same as multiple administrations ofimmediate release (or "regular") morphine.[10] Morphine sulfate pentahydrate (trade names including Dolcontin) has a highermolecular mass than morphine base, and therefore 10 mg morphine sulfate pentahydrate contains approximatively 7.5 mg of morphine free base.[11] Extended-release morphine can be administered together with "rescue doses" of immediate-release morphinepro re nata in case ofbreakthrough pain, each generally consisting of 5% to 15% of the 24-hour extended-release dosage.[10]
Some brands may have a pellet (spheroid) formulations (made by extrusion and spheronization) can be used for controlled release of the drug in the body whereas powder filled pellets generally cannot. The plastic spheres containing powder havemicropores that open at varyingpH levels, to maintain a mostly constant release during transit through thedigestive tract. The spheres themselves, the outer shells, pass undigested in most patients.[citation needed] Other brands are thought to useethylcellulose coatings to control drug release from pellets. Another use these medications have is that they can be given viaNG tube, the pellets being very small. This makes them one of the few extended release oral medications that can be given by feeding tube.
According to aCochrane review in 2013, extended-release morphine as anopioid replacement therapy for people withheroin addiction or dependence confers a possible reduction of opioid use and with fewerdepressive symptoms but overall more adverse effects when compared to other forms of long-acting opioids. The length of time in treatment was not found to be significantly different.[12]