Opioids: formulations and properties
| Opioids: formulations and properties |
Some preparations of opioids have immediate-release characteristics, others are available as modified-release formulations, and some are a combination of both.
Modified-release formulations should never be crushed or chewed, as this destroys their release properties and can result in a large dose being absorbed over a short period.
See Box 1.2 for advice about converting from immediate-release to modified-release morphine preparations.
A comparison of approximate equivalent doses of various opioids is shown in Table 1.4.
Table 1.3 below lists some opioid preparations and their properties. Awareness of the many available strengths and formulations is essential to avoid medication errors.
Properties of common opioid preparations available in Australia (Table 1.3) [NB1]
| Opioid | Active metabolite | Dose adjustment in renal impairment | Duration of action (hours) [NB2] | Preparation | |
| no | no | dose-related: 10 to 30 min for 1.5 to 3 mg/70 kg | injection | ||
| no | no | 6 to 8 | sublingual tablets (Temgesic) | ||
| injection (Temgesic) | |||||
| 7 days | transdermal patch (Norspan Transdermal Patch) | ||||
| yes | yes | 3 to 4 | linctus | ||
| tablet | |||||
| yes | yes | 6 to 12 (metabolite 30 to 36) | capsule | ||
| no | no | 0.5 to 2 | lozenge | ||
| injection | |||||
| 72 | transdermal patch (Durogesic) | ||||
| probable minimal effect except in patients with renal impairment | yes | 2 to 4 | oral liquid | ||
| tablet | |||||
| injection | |||||
| no | note that duration of effect increases with chronic dosing | 6 to 8 initially, then increases with chronic dosing up to greater than 24 hours | syrup | ||
| tablet | |||||
| injection | |||||
| yes | yes | 2 to 3 | injection (sulfate) | ||
| injection (tartrate) | |||||
| immediate-release oral mixture | |||||
| immediate-release tablet | |||||
| 24 | modified-release capsule (MS Mono) | ||||
| 12 | modified-release suspension (MS Contin) | ||||
| modified-release tablet (MS Contin) | |||||
| 12 to 24 | modified-release capsule (Kapanol) | ||||
| yes | yes | 3 to 4 | oral liquid (OxyNorm Liquid) | ||
| immediate-release capsule (OxyNorm) | |||||
| immediate-release tablet (Endone) | |||||
| 12 | modified-release tablet with immediate-release component (OxyContin) | ||||
| uncertain | suppository (Proladone) | ||||
| 4 | injection (Oxynorm Injection) | ||||
| yes | yes | 2 to 3 | injection | ||
| no | no | dose related (biological half-life of 3 to 10 minutes) | injection | ||
| no | yes | dose-related (40 to 87 min) | injection | ||
| yes | yes | 3 to 6 | immediate-release capsule | ||
| immediate-release oral drops | |||||
| injection | |||||
| 12 | modified-release tablet | ||||
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