Morphine and other opioids

Morphine will be described in detail and other opioid analgesics principally in so far as they differ. Morphine acts mainly on the opioid p,-receptor (analgesia, euphoria, dependence) and p2-receptors (respiratory depression, reduced gut motility). The principal actions of morphine may be summarised:

On the central nervous system:

• Depression, leading to: analgesia, respiratory depression, depression of cough reflex, sleep

• Excitation, leading to: vomiting, miosis, hyperactive spinal cord reflexes (some only), convulsions (very rare)

• Changes of mood: euphoria or dysphoria

• Dependence; affects other systems too.

Peripheral nervous system:

• Analgesia, some anti-inflammatory effect

Smooth muscle stimulation:

• Gastrointestinal muscle spasm (delayed passage of contents with constipation)

• Biliary tract spasm

• Bronchospasm

Cardiovascular system:

• Dilatation of resistance (arterioles) and capacitance (veins) vessles.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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