What is the difference between pethidine and morphine

From a macro perspective, both pethidine and morphine have analgesic effects. There are some differences in the therapeutic use of the two. Demerol is prohibited from use in some brain injury diseases, while morphine can be used for some more acute and chronic symptoms to relieve pain.

The adverse reactions of therapeutic doses of pethidine are similar to those of morphine, such as dizziness, discharge, dry mouth, nausea, vomiting, and tachycardia. Patients are prone to orthostatic hypotension. Repeated use can also cause addiction, but the addiction is milder than morphine and the progression is slower. Withdrawal symptoms may also occur if the drug is stopped suddenly, but they last for a shorter period of time.

Toxic doses can depress breathing, and addicts may develop tolerance to the central nervous system depressant effects of pethidine. Repeated administration of large doses of pethidine in a short period of time can produce central nervous system excitement symptoms such as tremors, muscle contractures, hyperreflexia, and even convulsions. This is caused by norpethidine, a metabolite of meperidine.

Demerol is contraindicated in patients with brain injury, suspected intracranial space-occupying lesions, chronic obstructive pulmonary disease, and bronchial asthma. Use with caution in patients with severe hepatic impairment. Morphine is effective for various types of pain such as dull pain, sharp pain or colic, but because it is addictive, it is generally only used when other analgesics are ineffective for acute and sharp pain such as severe trauma, combat injuries, burns, etc. In addition to inhaling oxygen, injecting aminophylline and rapid-acting cardiac glycosides, intravenous injection of morphine can often achieve good results in the treatment of cardiac asthma. It can relieve patients' shortness of breath and suffocation and promote the absorption of pulmonary edema fluid. Morphine can be used for acute and chronic diarrhea to relieve symptoms, and opium tincture or compound camphor tincture can often be used. Morphine is addictive and withdrawal symptoms may occur once the drug is stopped. Morphine can inhibit the breathing of the newborn through the placenta or breast milk. It can also counteract the stimulating effect of oxytocin on the uterus and prolong labor. Therefore, it is contraindicated for analgesia during labor and for lactating women.

Codeine's effects are similar to those of morphine, but weaker than morphine. Its analgesic effect is 1/2 of that of morphine based on equivalent dose, but it is slightly stronger than antipyretic analgesics. Although its inhibition on the cough center is not as strong as morphine, it can achieve satisfactory antitussive effect. Its absorption inhibition, euphoria and addiction are weaker than morphine. Mainly used for cough relief and analgesia. Codeine is a typical centrally acting antitussive drug, and new antitussive drugs are often compared with it in terms of their potency. It can also be used to relieve moderate pain.