Morphine
Morphine is an opioid used for background and breakthrough pain relief.
Indications
Pain Dyspnoea
Pharmacokinetics
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Pharmacodynamics
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Dosing and routes of administration
Morphine can be given orally and subcutaneously. Given its oral bioavailability, a subcutaneous dose of morphine should be around one-third to one-half of the oral dose. Dosing in an opioid naïve patient is age related and typical starting doses may be:
| Age | Form and route | Typical starting dose | |
| Young and middle aged adult | Oral immediate release | 10mg for breakthrough pain | |
| Oral modified release | 10mg twice daily | ||
| Subcut stat | 5mg for breakthrough pain | ||
| CSCI | 15mg over 24 hours | ||
| Elderly adult | Oral immediate release | 5mg for breakthrough pain | |
| Oral modified release | |||
| Subcut stat | 2.5mg for breakthrough pain | ||
| ::: O | CSCI | 10mg over 24 hours |
Equianalgesic doses
1mg of subcut morphine = 3mg or oral morphine = 1mg of SC oxycodone = 2mg of oral oxycodone = 0.2mg of subcut hydromorphone = 0.6mg of oral hydromorphone = 15 microgs of subcut fentanyl
Equivalence tables only give approximate doses and it is always wise to use caution and be conservative in dosing when undertaking a conversion.
| Morphine (milligrams) | Oxycodone (milligrams) | Fentanyl (micrograms) | |||
| Oral | Subcut | Oral | Subcut | Patch | Subcut |
| 5 | 2.5 | 5 | 2.5 | 25 | |
| 10 | 2.5-5 | 10 | 2.5-5 | 50 | |
| 15 | 5 | 10 | 5 | 75 | |
| 20 | 5-7.5 | 15 | 5-7.5 | 100 | |
| 30 | 10 | 20 | 10 | 150 | |
| 45 | 15 | 30 | 15 | 225 | |
| 60 | 20 | 40 | 20 | 300 | |
| 90 | 30 | 60 | 30 | 450 | |
| 120 | 40 | 80 | 40 | 600 | |
| 180 | 60 | 120 | 60 | 900 | |
| 240 | 80 | 160 | 80 | 1200 | |
| 300 | 100 | 200 | 100 | 1500 | |
| A 20mg buprenorphine patch approximately equals a 12microgram/hour fentanyl patch | |||||
Compatibilities in a CSCI
Morphine can be mixed safely with a large combinations of other medications in a continuous subcutaneous infusion.
| Second Drug | Diluent | |
|---|---|---|
| Morphine + | Cyclizine | Water |
| Haloperidol | Water or Saline | |
| Hyoscine butylbromide | Water | |
| Ketamine | Saline | |
| Levomepromazine | Water or Saline | |
| Metoclopramide | Water or Saline | |
| Midazolam | Water or Saline | |
| Octreotide | Saline | |
| Ondansetron | Water or Saline |
| Second Drug | Third Drug | Diluent | |
|---|---|---|---|
| Morphine + | Cyclizine + | Midazolam | Water |
| Halperidol + | Cyclizine | Water | |
| Hyoscine butylbromide | Water or Saline | ||
| Ketamine | Saline | ||
| Midazolam | Water or Saline | ||
| Octreotide | Water or Saline | ||
| Hyoscine butylbromide + | Octreotide | Saline | |
| Ondansetron | Saline | ||
| Ranitidine | Water | ||
| Levomepromazine + | Hyoscine butlybromide | Water or Saline | |
| Metoclopramide | Water or Saline | ||
| Midazolam | Water or Saline | ||
| Octreotide | Water or Saline | ||
| Ranitidine * | Water | ||
| Metoclopramide + | Ondansetron | Saline | |
| Ranitidine | Saline | ||
| Midazolam + | Cyclizine | Water | |
| Hyoscine butylbromide | Water or Saline | ||
| Ketamine | Water or Saline | ||
| Octreotide | Water or Saline | ||
| Ondansetron | Saline | ||
| * Add ranitidine last once all other drugs and diluent have been combined. Precipitation reported with high doses of levomepromazine > 75mg | |||
| Second Drug | Third Drug | Fourth Drug | Diluent | |
|---|---|---|---|---|
| Morphine + | Haloperidol + | Cyclizine + | Octreotide | Water |
| Ranitidine | Water | |||
| Hyoscine butlybromide + | Ranitidine | Water | ||
| Midazolam + | Cyclizine | Water | ||
| Hyoscine butylbromide | Water | |||
| Levomepromazine + | Hyoscine butylbromide + | Octreotide | Saline | |
| Ranitidine * | Water | |||
| Midazolam + | Hyoscine butylbromide | Water | ||
| Ketamine | Saline | |||
| Metoclopramide | Water or Saline | |||
| Ondansetron | Water | |||
| Metoclopramide + | Midazolam + | Ketamine | Saline | |
| Octreotide | Water or Saline | |||
| Ondansetron + | Octreotide | Saline | ||
| Midazolam + | Hyoscine butylbromide + | Octreotide | Saline | |
| Cyclizine + | Ondansetron | Water | ||
| * Add ranitidine last once all other drugs and diluent have been combined. Precipitation reported with high doses of levomepromazine > 75mg | ||||