Eliminate the patient's fear, tension and anxiety about surgery, make the patient emotionally stable and cooperative, and produce necessary amnesia (amnesia)

Increase the patient's pain threshold, enhance anesthesia effect, reduce anesthetic dosage, and relieve pain caused by pre-operative and pre-anesthetic operations

Such as increased respiratory secretions, toxic effects of local anesthetics, etc.

Adjust autonomic nervous function to eliminate or avoid adverse neural reflex activities, such as adverse vagal reflexes

Such as reducing gastric juice volume and acidity, antiemetics, preventing or combating allergic reactions

benzodiazepines

Butyrophenones

Phenothiazines

Mainly barbiturates, which have sedative, hypnotic, and anticonvulsant effects and are often used to prevent toxic reactions of local anesthetics

Commonly used drugs include phenobarbital (long-acting), pentobarbital (medium-acting, now less used), secobarbital (short-acting), etc. The role of barbiturates in preventing local anesthetic poisoning has been gradually replaced by benzodiazepines. Those who still use barbiturates mostly use phenobarbital sodium 1~2 mg/kg for intramuscular injection 1 hour before the day of the day.

Narcotic analgesics (narcotics) are also called central analgesics. Since these drugs are all opioid alkaloids or their semi-synthetic derivatives, they are often called opiates. These drugs all have strong analgesic effects, can increase the pain threshold, and some have obvious sedative effects; they have synergistic effects with general anesthetics, and can also be used as auxiliary drugs to improve the effects of other anesthesia, or for postoperative use. analgesia

morphine

pethidine or dolantin

methadone

Anticholinergics (anicholinergics) used before anesthesia are all M-choline receptor blockers.

Commonly used drugs: atropine and scopolamine (scopolarnine, hyoscine)

This drug is a reversible, competitive H2 histamine receptor antagonist that can inhibit gastric acid secretion caused by histamine, gastrin and M-choline receptor agonists, reducing gastric juice volume and [H+] in gastric juice. It is generally not used as a routine pre-anesthetic medication. It is mainly used for patients with insufficient preoperative preparation and the risk of gastric reflux and laboring women. It can reduce the risk of reflux and aspiration, as well as the severity of aspiration.

Currently used clinically are cimetidine, ranitidine, famotidine and nizatidine

Patient condition

Intended anesthetic method and anesthetic agent

① Give oral hypnotics or sedatives and tranquilizers the night before surgery to eliminate the patient’s nervousness and ensure better sleep and rest. ② Pre-anesthetic medication on the day of surgery generally uses sedatives, diazepam or eye drops to eliminate the patient's nervousness, anxiety and fear, so that the patient can be emotionally stable and fully cooperative before anesthesia. If the patient has severe pain or pain, additional sedatives should be used. Analgesics may also be given if the patient is undergoing a painful procedure. Morphine is often used to enhance sedation, especially in patients with heart disease. M-choline receptor blockers are given according to specific circumstances to reduce the secretion of mucus in the trachea and bronchus and reduce the excitability of the vagus nerve.

Those who need to reduce the dosage of inhibitory drugs such as sedatives, tranquilizers, hypnotics, and central analgesics as appropriate

Those who need to increase the dose of inhibitory drugs as appropriate

Central analgesics are prohibited or used with caution

The dosage of anticholinergic drugs should be larger

It is advisable not to use or use less anticholinergic drugs

When multiple pre-anesthetic drugs are used together, the dosage should be adjusted accordingly according to the effects of the drugs.

For emergency patients, intravenous medication is appropriate when necessary