Diamorphine

From Ganfyd

Jump to: navigation, search

Diamorphine is an opioid analgesic. It is the diacetylated form of morphine, from which the name diamorphine derives.

Contents

History

The first synthetic opioid, it was originally synthesized by Charles Wright at St. Mary's Hospital, London in 1874 but was not used as a medicine until marketed from 1898 under the trade name Heroin (Heroïne) by Bayer. Together with aspirin, it helped to make Bayer's fortune. Its synthesis was made illegal in the USA in 1924. Use has considerably reduced in Britain, the main legal medicinal market during 2005 due to supply problems, and is projected not to return to previous levels simply because it is more expensive than morphine for most indications.

Clinical Use

By the early 1980's British doctors were writing just under 99% of the world's prescriptions for medicinal diamorphine and consuming 95% of the worldwide legally produced annual quantity of about 300 kg of diamorphine (United Nations International Narcotic Control Board, 1990). There is clinical trial evidence that 5mg iv gives more prompt pain relief than 10mg morphine in myocardial infarction[1] but this may not be of clinical significance.

Indications

Where a high solubility opioid is required.

Administration

IV or Epidural

Clinical Issues

Its use even for medical purposes is illegal in many countries.

Toxicity

Contra-indications

Cautions and Interactions

Side effects

  • Nausea and vomiting
  • Constipation
  • Drowsiness
  • Respiratory depression
  • Dependence
  • Hallucinations & Confusion

Special advice

Pharmacology

Diamorphine is the diacetylated form of morphine. Being more soluble than morphine, it readily crosses the blood-brain barrier where it is subsequently hydrolysed to 6-monoacetylmorphine (6-MAM) and morphine. Hydrolysis to 6-MAM occurs rapidly and measurement of 6-MAM in autopsy toxicology is a method for confirming ante-mortem diamorphine use.

The detection of other opiate compounds in the blood, e.g. noscapine and thebaine suggests the diamorphine was derived from an illicit source rather than pure medical grade diamorphine.

References