Pharmacodynamics
Pharmacological effects
Has antihistamine, sedative, anti-motion sickness, antiemetic and anticholinergic effects.
1)Antihistamine effect: Competes with histamine released by tissue for H1 receptors, which can antagonize the effect of histamine on the gastrointestinal tract, trachea, bronchi or bronchioles Smooth muscle contraction and contracture, relieve the spasmodic and hyperemic effect of histamine on bronchial smooth muscle.
2) Antiemetic effect: It may be related to the inhibition of the emetic chemoreceptor area of the medulla oblongata.
3) Anti-motion sickness: It may act on the vestibular and emesis centers and midbrain medullary receptors through central anticholinergic properties, mainly blocking the vestibule Excitation of vagal impulses at nuclear cholinergic synapses.
4) Sedative and hypnotic effect: It may be due to indirectly reducing the excitability of the brainstem reticular ascending activation system.
Mechanism of action
Promethazine, a phenothiazine derivative, is a competitive H1 receptor antagonist, but does not block the release of histamine. Structural differences with the antipsychotic phenothiazine lead to its relative lack (1/10 of chlorpromazine) dopamine antagonist properties.
Domestic approved indications
Oral administration
1. IsoPromazine Bile Tablets: For cough caused by cold, whooping cough and its paroxysmal, spasmodic cough.
2. Promethazine Hydrochloride Tablets:
1)Skin and mucous membrane allergies: Applicable to long-term, seasonal allergic rhinitis, vasomotor rhinitis, contact Allergic conjunctivitis due to allergens or foods, urticaria, angioedema, allergic reactions to blood or plasma products, skin scratching. When necessary, it can be used in combination with epinephrine as an adjuvant of this drug.
2) SicknessMotion sickness: Prevention of motion sickness, seasickness, and plane sickness.
3) Sedation, Hypnosis: Suitable for preoperative, postoperative and obstetrics. In addition, it can also be used to reduce the fear of adults, showing a light sleep state.
4) NauseaTreatment of heart and vomiting: Applicable to some nausea and vomiting after anesthesia and surgery, and also used to prevent and treat radiation sickness Sexual or drug-induced nausea and vomiting.
5) Postoperative painPostoperative: It can be used in combination with analgesics as an adjunct.
Injection administration
1)Allergic skin and mucous membranes: Applicable to long-term, seasonal allergic rhinitis, vasomotor rhinitis, allergic rhinitis Conjunctivitis, urticaria, angioedema, allergic reactions to blood or plasma products, skin scratching.
2)Motion sickness: Prevent motion sickness, seasickness, and plane sickness.
3) for anesthesia and adjuvant therapy before and after surgery, including sedation, hypnosis, analgesia , stop vomiting.
4) for the prevention and treatment of radiation-induced or drug-induced nausea and vomiting.
Domestic routine dosage
Oral administration
1.Promethazine Bile Tablets: Oral. 12.5 mg once, 3 times a day.
2. Promethazine Hydrochloride Tablets:
1)Anti-allergic: 12.5 mg once, 4 times a day, after meals and before bedtime, 25 times before bedtime if necessary mg;
2)Antiemetic: 25 mg once at the beginning, 12.5~25 mg every 4~6 hours if necessary;< /p>
3)Anti-dizziness: 25 mg once, 2 times daily if necessary;
4)Sedation and Hypnosis: 25~50 mg once, double if necessary.
Injection Administration: Injections
1)Anti-allergicallergy: 25 mg once, repeated 2 hours later if necessary; intramuscular injection of 25-50 mg is available for severe allergies, and the maximum dose should not exceed 100 mg.
2) In special emergency situations, it can be diluted to 0.25% with sterile water for injection and injected intravenously slowly.
3)Antiemetic: 12.5~25 mg once, repeat every 4 hours if necessary.
4)Sedation and Hypnosis: 25~50 mg once.
FDA Boxed Warning
1. Respiratory Depression: Pediatric Patients
Promethazine Hydrochloride Injection should not be used in pediatric patients younger than 2 years of age and may cause fatal respiratory depression. Postmarketing cases of respiratory depression (including deaths) have been reported with promethazine in pediatric patients under 2 years of age. Caution should be exercised when administering promethazine hydrochloride to pediatric patients 2 years of age and older.
2. Severe tissue damage (including gangrene)
(1) Regardless of the route of administration, promethazine hydrochloride injection can cause severe chemical irritation and tissue damage, which may be caused by perivascular and external Infiltration, intraarterial injection, and intraneuronal or perineuronal infiltration.
(2) Adverse reactions include burning sensation, pain, thrombophlebitis, tissue necrosis and gangrene. In some cases, surgical intervention, including fasciotomy, skin grafting, and/or amputation, is required.
3. Due to the risk of intravenous injection, the preferred route of administration of promethazine hydrochloride injection is deep intramuscular injection, subcutaneous injection is prohibited.
The content is for reference only, please combine clinical practice
Source | Medication Assistant App