Actions of Morphine

(By Dr. Ahmad Najmi, Index Medical College, Indore)
The main pharmacological effects are:

* analgesia

* euphoria and sedation

* respiratory depression-can lead to respiratory failure-apnoea.
* suppression of cough-is used as cough suppressent

* nausea and vomiting-Due to CTZ stimulation

* pupillary constriction-pinpoint pupil

* reduced gastrointestinal motility, causing constipation

* histamine release, causing bronchoconstriction-contraindicated in astmatics and hypotension.

* The most troublesome unwanted effects are constipation and respiratory depression.

* Morphine may be given by injection (intravenous or intramuscular) or by mouth, often as slow-release tablets.

* Acute overdosage with morphine produces coma and respiratory depression.- is treated by naloxone- antidote

* Morphine is metabolised to morphine 6-glucuronide (M6G), which is more potent as an analgesic.

* Morphine and M6G, are the active metabolites of diamorphine and codein