Diamorphine
Diamorphine is a more potent opioid analgesic than morphine. It is used for the relief of severe pain especially in palliative care.
| Generic Name 藥名 | HA Code 藥物代碼 | Classification藥物分類 |
|---|---|---|
| Diamorphine | DD |
Mechanism of Action[edit]
Equivalent doses of opioid analgesics
| Analgesic/Route | Dose |
|---|---|
| Codeine: PO | 100 mg |
| Diamorphine: IM, IV, SC | 3 mg |
| Dihydrocodeine: PO | 100 mg |
| Morphine: PO | 10 mg |
| Morphine: IM, IV, SC | 5 mg |
| Oxycodone: PO | 6.6 mg |
| Tramadol: PO | 100 mg |
Route of Administration : IV
Dosage[edit]
For severe acute pain:
Subcutaneous or intramuscular: 5 to 10 mg every 4 hours.
For the pain of myocardial infarction
Slow intravenous: doses of 5mg are given at a rate of 1 to 2 mg/minute with a further dose of 2.5 to 5 mg if required.
For chronic severe pain:
Subcutaneous or intramuscular: 5 to 10 mg every 4 hours; the dose may be increased according to needs.
Administration in children[edit]
Doses according to age or body-weight, and adjusted according to response:
By intravenous injection:
- 1 to 2 months: 20 micrograms/kg every 6 hours
- 3 to 5 months: 25 to 50 micrograms/kg every 6 hours
- 6 to 11 months: 75 micrograms/kg every 4 hours
- 1 to 11 years: 75 to 100 micrograms/kg (maximum of 5 mg) every 4 hours
Side Effects[edit]
Opioid Analgesic in general[edit]
The commonest adverse effects are nausea, vomiting, constipation, drowsiness and confusion.
Large doses of opioids produce respiratory depression and hypotension, with circulatory failure and deepening coma. Death may occur from respiratory failure.
Treatment of Adverse Effects[edit]
- Constipation can be treated with laxatives such as senna tables and lactulose.
- Nausea and vomiting can be alleviated by metoclopramide.
- Intensive supportive therapy may be required to correct respiratory failure and shock. Naloxone is used for rapid reversal of the severe respiratory depression and coma.
Euphoria, nausea and vomiting, respiratory depression, constipation and cough suppression.
Pharmacokinetics[edit]
| Oral bioavailability | Diamorphine hydrochloride is well absorbed after subcutaneous or intramuscular injection.It readily crosses the blood-brain barrier. |
|---|---|
| Onset of action | |
| Metabolism | It is mainly excreted in the urine. |
| Elimination half-life |
Drug Management[edit]
Efficiency[edit]
Relief of moderate to severe pain, especially that associated with cancer, myocardial infarction and surgery.
Contraindication[edit]
- acute respiratory depression and obstructive airways disease
- acute alcoholism
- convulsive disorders
- head injuries
- avoid in patients at risk of paralytic ileus
- patients with hypothyroidism
- patients with adrenocortical insufficiency
- renal or hepatic impairment
- prostatic hyperplasia
Drowsiness may affect the ability to perform skilled tasks; those so affected should not drive or operate machinery. Morphine should be stopped gradually in patients who may have developed physical dependence, to avoid precipitating withdrawal symptoms (see Dependence )
Abrupt withdrawal of opioids precipitates a withdrawal syndrome. With morphine and diamorphine, withdrawal symptoms usually begin within a few hours, reach a peak within 36 to 72 hours, and then gradually subside; they develop more slowly with methadone.
Withdrawal symptoms include yawning, mydriasis, rhinorrhea, sneezing, muscle tremor, weakness, sweating, nausea vomiting, diarrhoea, bone pain, abdominal and muscle cramps, increases in heart rate, respiratory rate, blood pressure and temperature.
Safety[edit]
Mental status, blood pressure, respiratory drive, and misuse/overuse.
Caution[edit]
Toxic psychosis, CNS depression, severe, cor pulmonale
Tolerance and dependence
Contraindication[edit]
Where hepatic and renal impairment may result in toxicity
FAQ[edit]
What should I avoid while taking?[edit]
Avoid abrupt withdrawal
What happen if I overdose?[edit]
Emergency situation, called 999 immediately Antidote: Naloxone
What happen if I miss a dose?[edit]
Administered by professionals
