What is the mechanism of morphine analgesia?

The mechanism of action of morphine drugs: by combining with opioid receptors in different brain regions, it simulates the role of endogenous opioid peptides, inhibits the release of substance P, and interferes with the afferent center of pain impulses to play an analgesic role. The affinity and intrinsic activity of morphine drugs to different types of opioid receptors are not completely the same, and the combination with opioid receptors in the glial region of spinal cord, medial thalamus, ventricle and periaqueductal gray of midbrain can cause analgesic effect.

clinical application

1. Analgesic morphine is effective for acute pain, dull pain and visceral colic, but it is easy to become addictive after long-term use, so it can only be used for short-term acute pain, such as severe trauma, war injury and burning pain. For acute pain caused by myocardial infarction, morphine can be used to relieve pain if blood pressure is normal.

2. Patients with cardiogenic asthma and left heart failure can suddenly develop acute pulmonary edema and cause shortness of breath and asphyxia, which is called cardiogenic asthma. Besides oxygen inhalation and intravenous injection of quick-acting cardiac glycoside and aminophylline, intravenous injection of morphine can also produce good results. Its mechanism of action is: (1) Morphine has sedative effect, which is beneficial to eliminate the fear and anxiety caused by asphyxia; (2) Morphine reduces the sensitivity of respiratory center to CO2 and reduces uncompensated respiratory overexcitation; (3) Morphine dilates peripheral blood vessels and reduces peripheral resistance, which is beneficial to eliminate pulmonary edema and reduce heart load. However, it is forbidden for coma, shock and severe pulmonary insufficiency.

3. Antidiarrhea is suitable for relieving symptoms of acute and chronic consumptive diarrhea. Opioid tincture or compound camphor tincture can be selected; If it is a bacterial infection, you should also take antibacterial drugs.