Promedol (solution for injections 2%)
Solutio Promedoli 2% pro injectionibus
International unlicensed name
Trimeperedin hydrochloride.
Pharmacotherapy group
Opioids.
Composition
1 ml of solution for injections contains trimeperedin hydrochloride 20 mg.
Pharmacological action
Pharmacodynamics
Promedol is a narcotic anaesthetic (opioid analgesic). Like morphine and fentalyn, it is an agonist of opioid receptors. It activates the endogenous antinociceptic system and thus disturbs the interneurotic transmission of pain impulses on different levels of the central nervous system, as well as changes the emotional perception of the pain affecting the highest brain parts. The pharmacological properties of promedol are close to those of morphine: it increases the pain threshold on pain incentives of different modality, depresses conditioned reflexes, has a moderate soporific effect. Unlike morphine, it depresses the respiratory centre to a lower extent and more rarely induces nausea and vomiting, has a moderate spasmolytic effect onto the bronchi and ureters, it is inferior to morphine in spasmogenic effect onto the bile passage and intestine. Promedol slightly increases the tone and myometria contraction activity.
On subcutaneous and intramuscular administration the action of promedol starts in 10—20 minutes and lasts 2—4 hours and more.
Pharmacokinetics
On intravenous administration the max.concentration in blood is achieved in 15 minutes. Then a rapid drop of the content in plasma is observed, and in 2 hours only trace concentrations are found. Bounding with plasma proteins makes 40%. It metabolizes by the hydrolysis with formation of meperidin and normeperidin acids followed by conjugation. In small quantities it is excreted unaltered.
Indication
Promedol is used either in adults, or in children older than 2 years old on moderate and intensive pains, mainly of traumatic origin, in the preoperational, operational and postoperational periods, on myocardical infarct, severe stencardia attacks. The preparation is effective on a pain syndrome related to the smooth muscle spasm in the inner organs (in combination with atropine-like and spasmolytic preparations), on pains induced by malignant swellings. In obstetrics it is used for anaesthetization of the labor.
Route and dosage
It is prescribed subcutaneously, intramuscularly and, in case of emergency, intravenously. In adults it is administered subcutaneously and intramuscularly from 0,01 to 0,04 г (from 1 ml of solution 1% up to 2 ml of solution 2%). Under anaesthetic the preparation by small doses is administered (0,003—0,01 g). In case of pains caused by smooth muscle spasm (hepatic, renal, intestinal colic) promedol shall be combined with atropine-like and spasmolytic preparations under a thorough control. For premedication before the anesthesia the preparation is administered subcutaneously or intramuscularly 0,02—0,03 g with atropine (0,0005 g) 30—45 minutes before the operation. For the labor anaesthetization it is administered subcutaneously or intramuscularly in the doses of 0,02—0,04 g on fauces dilatation at 3—4 sm, the fetus’s condition being satisfactory (it has a spasmolytic action onto the uterus cervix accelerating its dilatation). The last dose of the preparation should be administered 30—60 minutes before the delivery in order to prevent the narcotic depression of the fetus and the new-born child.
The highest doses in adults should be administered parenterally: single — 0,04 g, daily — 0,16 g.
In children older than 2 years old promedol is prescribed in the doses 0,003—0,01 g depending on the age. The preparation is contraindicated for children younger than 2 years old.
Special indications
Alcohol is prohibited during the course of treatment. Promedol complicates the performance of work requiring a high speed of psychic and physical reactions.
Side effects
On administration of the preparation the following case have been registered: nausea, vomiting, disorientation, dizziness, muscle weakness, sensation of slight intoxication (euphoria) that pass away without using special medications. In such cases the dose of the preparation should be reduced.
On repeated use of promedol addiction to its components or opioid may develop (weakening of anesthetic action).
Contraindications
Higher individual intolerance to the preparation, general emaciation, young age (up to 2 years) and old age, as well as conditions accompanied by respiratory depression.
Precautions
It should be taken with care in patients with indication to opioid addiction in the anamnesis.
Interaction with other medications
Promedol should be administered with care on the basis of action of narcotic agents, soporifics and neuroleptics in order to prevent an excessive depression of the central nervous system and suppression of the respiratory centre activity. Promedol should not be combined with narcotic analgesic of agonist-antagonist group (nalbuphine, buprenorphine, butorphanol, tramadol) of opioid receptors because of danger of analgesia weakening. On the basis of systemic administration of barbiturates, esp.phenobarbital, it is possible that anesthetic action of opioid analgesics weakens.
It should not be combined with monoaminoxidase inhibitors (excitation and convulsions are possible). A prolonged administration of barbiturates or opioid analgesics stimulates the cross tolerance development.
Anesthetic action and undesired side effects of opioid agonists (morphine, fentanyl) in the therapeutic range of doses are added to the action of promedol.
Overdosing
Symptoms: on intoxication and overdosing stuporous or comatose condition may develop; respiratory depression is registered. The characteristic peculiarity is apparent myosis (on severe hypoxia the pupils may be dilatated).
Treatment: keeping an adequate lung ventilation. Intravenous administration of specific naloxone opioid antagonist in the dose from 0,4 till 0,2 mg is required (the desired effect not achieved, administration of nalozone should be repeated in 2 -- 3 minutes). The initial dose of naloxone in children is 0,01 mg/kg.
Product form
Solution for injections 2%. 1 ml in vials. 10 vials in a package.
