Morphine is the most abundant analgesic opiate found in opium and is a potent pain reliever. The drug is used in clinical pain relief but is also used illicitly for recreational purposes among drug users. It is potentially highly addictive and can cause intense physical dependence that leads to abuse of the substance.
Morphine is obtained from the seedpod extract or opium found in the poppy plant, Papaver somniferum.
Morphine is widely used in clinical pain management, especially for terminal cancer pain and post-surgery pain. In the body, morphine has several effects including reduction of pain, loss of hunger, and suppression of cough.
Some of the clinical uses of morphine include:
Morphine is sold clinically under brand names MSiR®, MS-Contin®, Roxanol®, RMS®, Kadian® and oramorph SR®.
Due to the euphoric effects of the drug, morphine is also commonly used illegally by drug abusers. Some of the street names for morphine include God's Drug, MS, Morf, Morpho, Dreamer, First Line, Emsel, Unkie and Mister Blue.
In previous decades, the injectable form of morphine was most commonly used. However, today it is taken in the form of a pill, a drinkable solution or a suppository.
Once injected or ingested, morphine enters the blood stream which carries it to the brain and other parts of the body where it activates opioid receptors to exert the effects of the drug. Activation of the μ1 receptor subtype leads to pain relief, while activation of the μ2 receptor can cause effects such as respiratory depression and addiction. Sedation or sleepiness is caused by morphine's activation of the κ receptor subtype.
Repeated use of morphine can lead to individuals developing tolerance of the drug and a physical and psychological dependence on it. Tolerance describes when an increased dose of the drug is needed if a person is to expereince the same pleasurable effects as they expereinced with a previous smaller dose because the effects have become blunted when this same smaller dose is used.
Worldwide, morphine is a Schedule I drug under the Single Convention on Narcotic Drugs. In the Unites Sates, morphine is a Schedule II drug under the Controlled Substances Act and in the UK, it is a Class A drug under the Misuse of Drugs Act 1971 and a Schedule 2 controlled Drug under The Misuse of Drugs Regulations 2001.it is classified as a Schedule 8 drug under State and Territory Poisons Acts.