Phentanyl (solution for injections 0.005%)
Solutio Phentanyli pro injectionibus 0.005%
International not patented name
1 ml of the solution for injections contains 0.05 mg of phentanyl.
Phentanyl excites the SNC opiate receptors (mostly µ-receptors), bone marrow and peripheral tissues receptors. It enhances the anti-nociceptive system activity, increases the pain sensitivity threshold. The preparation changes the pain emotional coloring.
Phentanyl has a strong though a short-time (when injected once) analgesic effect.
When introduced intravenous the maximal effect develops in 1 – 3 minutes and lasts for 15 – 30 minutes. When injected intramuscular the maximal effect is registered in 3 – 10 minutes.
Up to 79% of phentanyl is fixed on blood proteins. The clearance is 0.4 – 0.5 l/min. The period of half elimination is 10 – 30 minutes. The preparation redistributes from blood and brain to muscles and adipose tissue. It is biotransformed in the liver, kidneys, intestine and adrenal gland. It is excreted with urine (75% of phentanyl as metabolites and 10% – unchanged) and with feces (9% of the preparation as metabolites). It penetrates into breast milk.
Indications for appliance
Phentanyl is applied mostly for neuroanalgesia in combinations with neuroleptics.
Phentanyl may be used for cupping acute pain under myocardial infarction, stenocardia, pulmonary infarction, renal and hepatic colics.
Mode of appliance and dosage regime
For providing neuroanalgesia first a neuroleptic is introduced, than phentanyl its dose calculated as 1 ml of 0.005% solution for every 5 kg of the patient’s body mass. The preparation is injected slowly intravenous. For an introduction narcosis twice smaller doses of phentanyl followed by barbiturates or other narcotic preparations in reduced doses introduction may be used.
As a rule after neuroleptics and phentanyl injections the patient is injected a muscular relaxant, his trachea is intubated and a supplementary or an artificial ventilation of lungs with oxygen or a mixture of oxygen and nitrous oxide or with other inhalation narcotics in smaller concentrations is performed. For supporting the analgesic effect in case of necessity every 10 – 30 minutes 1 – 3 ml of 0.005% phentanyl solution is injected.
In case of long-time extracavitary operations when intramuscular relaxants are not needed and neuroleptanalgesia is performed on the background of the spontaneous breathing preserved phentanyl is injected in the dose calculated as 1 ml of 0.005% solution for every 10 – 20 kg of the patient’s body mass. In those cases it is necessary to monitor the spontaneous breathing and to have an opportunity when necessary to intubate the trachea and provide an artificial breathing.
When the operation is performed under a local anesthesia phentanyl (mostly in combinations with neuroleptics) may be applied as an additional analgesic preparation. 0.5 – 1 ml of 0.005% phentanyl solution is injected intravenous or intramuscular (in case of necessity the preparation injections may be repeated every 20 – 40 minutes).
For cupping acute pain under myocardial infarction, stenocardia, renal and hepatic colics pf is injected intramuscular or intravenous – 0.5 – 1 – 2 ml of 0.005% solution. Phentanyl injections are repeated every 20 – 40 minutes and after the operation – every 3 – 6 hours.
When artificial ventilation of lungs is not possible neuroleptanalgesia is prohibited.
During the treatment it is not recommended to be occupied with potentially dangerous activities requiring an increased attention and psychomotor reactions.
When phentanyl is injected especially when it is injected quickly intravenous the breathing suppression may occur.
Motor excitement, spasms and thorax and limbs muscles rigidity, bronchospasm, hypotension, sinus bradycardia may be observed.
Phentanyl appliance is prohibited for obstetric operations, under pronounced hypertension in the lesser arterial circle of blood circulation, the breathing center suppression, pneumonia, atelectasis and pulmonary infarction, bronchial asthma, susceptibility to bronchospasm, extrapyramidal system diseases, narcomania, pregnancy and lactation.
The preparation is withdrawn little by little. When phentanyl large doses are injected into undernourished and asthenic patients the breathing secondary depression conditioned by phentanyl excretion in 1 – 2 hours after the preparation is introduced into the stomach lumen and its subsequent resorption may develop.
Interaction with other medicinal preparations
The effect is decreased by buprenorphyne. Opiates, sedative preparations, soporific drugs, phenothiasines, narcotic preparations, myorelaxants, alcohol and other depriming preparations enhance the side effects probability.
Symptoms: breathing suppression.
Treatment: naloxone introduction, oxygen inhalation, AVL.
0.005% solution for injections in 2 ml vials. 10 vials in a cartoon.