It:Morphine

Introduction to Morphine

Morphine originates from the dried seeds of the poppy (Papaver somniferum.)Morphine is an extremely powerful analgesic drug, whcih is the principal active agent in opium. Morphine acts directly on the central nervous system to reduce pain. It has numerous side effects such as; impairment of mental performance, euphoria, drowsiness, lethargy and blurred vision. It also causes a decrease in hunger and promotes constipation. Morphine is highly addictive when compared to other substances.

Structure of Morphine

Properties of Morphine

Chemical Data
IUPAC Name	7,8-didehydro- 4,5-epoxy-17-methylmorphinan-3,6-diol
Chemical formula	C₁₇H₁₉NO₃
Molar Mass	285.4 g/mol
Pharmakenetic Data
Bioavailability	... ~30%
Protein binding	... 30–40%
Metabolism	... Hepatic 90%
Therapeutic Considerations
Pregnancy cat.	C(AU) C(US)
Legal status	S8(AU) Schedule I(CA) Class A(UK) Schedule II(US) Prescription only
Dependence Liability	Extremely High
Routes	smoked/inhaled, insufflated, Oral, SC, IM, IV

Uses

Morphine is used legally:

analgesic in hospital settings for
Pain after surgery
Pain associated with trauma
In the relief of severe chronic pain
Cancer pain
Pain from kidney stones
Back pain
In epidural anesthesia
As an antitussive for severe cough
As an antidiarrheal in chronic conditions (e.g., for diarrhea associated with AIDS)
To relieve breathlessness in patients in respiratory failure

Pharmacology of Morphine

Morphine is an opiod receptor agaonist whose main function is to bind and activate the µ-opioid receptors in the central nervous system.The activation of these receptors is what leads to euphoria, sedation, analgesia, physical dependence and respiratory depression. Morphine is also a κ-opioid receptor agonist, which is associated with spinal analgesia and miosis. These effects of Morphine can only be countered with naloxone or naltrexone.

Naloxone

Naltrexone

Both naloxone and naltrexone are competitive antagonists at the μ- and κ-opioid receptors, and to a lesser extent at δ-opioid receptors. The blockade of these receptors is what prevents the opiods such as morphine, from combining with these receptor sites thus preventing the side effects usually caused by morphine.

Derivatives of Morphine

Morphine can be used to synthesize a variety of different opiates. Some of the most prominent examples include:

Morphine

Codeine

Heroin

When comparing the structures of Morphine with those of Codeine and Heroine, it becomes clear that there are only slight differences. If one of the OH groups from Morphine (marked in red) is replaced by a OMe group it becomes codeine. If these -OH groups are both replaced bu CH₃COO group it becomes heroin.
Codeine is used as an analgesic, in a similar way to morphine. It is not as effective as morphine, however the addiction potential is much lower than that of morphine.
Heroin acts as a very strong analgesic with an extremely strong potential for addiciotn. For obvoius reasons the synthesis of heroin will be omited.

Contradications

Acute Respiratory Depression
Acute Alcoholism
Acute pancreatitis (this may be a result of morphine use as well)
Renal failure (due to accumulation of the metabolite morphine-6-glucuronide)

Synthesis of Codeine from Morphine

References and External Links

Morphine Apparently in Your Head -- Wired Magazine article about endogenous production of morphine
Morphine, Molecule of the Month
Opioid Analgesics
Schmitz J, Stotts A, Rhoades H, Grabowski J. "Naltrexone and relapse prevention treatment for cocaine-dependent patients.". Addict Behav 26 (2): 167-80. PMID 11316375.
Chicago Recovery Alliance's naloxone distrobution project
Synthesis of codeine from morphine. Ai, Lin; Chen, Xiaoyuan; Zhang, Le. Faming Zhuanli Shenqing Gongkai Shuomingshu (2005)