IDENTIFICATION AND USE: Lofentanil is a very potent opioid analgesic. It is used clinically in the management of pain. However, the high analgesic potency of this drug is limited by the development of tolerance after chronic use. HUMAN STUDIES: In patients side effects of very low incidence included nausea, vomiting and sedation. Another study mentions drowsiness in three patients as a side effect. ANIMAL STUDIES: Increasing doses of lofentanil (0, 0.08, 0.16, 0.31, 0.63, 1.25, 2.50, 5.00, and 10.0 ug/kg) were administered intravenously to rats to examine the relationship among central nervous system (CNS) depressant dosage, degree of analgesia (inhibition of tail withdrawal reflex), anesthesia (no response to bone-crush injury), and CNS opiate-receptor occupancy. Increasing doses of lofentanil produce increasing analgesia and anesthesia and eventually complete opiate receptor occupancy. Analgesia occurs with doses of lofentanil (0.31 ug/kg) that result in levels of CNS opiate-receptor binding too low to be measured and anesthesia occurs with doses of lofentanil (1.25 ug/kg) that produce occupancy of about 25% of the available opiate receptors in subcortical areas and cortex. In rats a dose eight times the anesthetic dose of lofentanil is needed to saturate virtually all available CNS opiate receptors (10.0 ug/kg).
/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on the left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Poisons A and B/
/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . /Poisons A and B/
/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W TKO /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poisons A and B/
Emergency and supportive measures. 1. Maintain an open airway and assist ventilation if necessary. Administer supplemental oxygen. Treat coma, seizures, hypotension, and noncardiogenic pulmonary edema if they occur. /Opiates and opioids/
(3)H-Lofentanil, an extremely potent opiate drug with a very long duration of action was injected intravenously into rats immediately after a ligature had been tied around the vagus nerve. Radioactivity accumulated on both sides of the ligature 24 hours and, to a larger extent, 48 hours after the injection. In contrast, there was no accumulation in animals pretreated with naloxone, neither in ligated sciatic nerves nor between two ligatures in the vagus nerve. An accumulation of stereospecific (3)H-lofentanil binding sites measured in vitro was only detected above the ligature, thus in the proximal part of the nerve. When (3)H-lofentanil was injected at different time intervals after ligation, we observed a tremendous drop of labelling in the distal and also but more slowly in the proximal part of the nerve. This could be due to a possible recycling or re-utilization of (3)H-lofentanil binding sites. The present data are compatible with an axoplasmic flow and a possible recycling of opiate receptors labelled in vivo after intravenous injection of (3)H-lofentanil.
The in vivo binding of (3)H-lofentanil was studied in various regions of the brain in rat. After intravenous injection of (3)H-lofentanil the disposition of the labelled drug in the brain paralleled exactly the regional distribution of opiate receptors measured in in vitro binding assays. The labelling was saturable and could be prevented by naloxone when given before (3)H-lofentanil, in all the regions except in the cerebellum. The long-lasting occurrence of the specific labelling was entirely compatible with the extremely slow dissociation rate of lofentanil and its long duration of action. This explains why (3)H-lofentanil is not displaceable by naloxone in vivo. Subcellular fractionation experiments revealed that all the labelling in the frontal cortex but not in the cerebellum was particulate-bound and entirely displaceable by naloxone. The advantages of (3)H-lofentanil in vivo are its extremely low non-specific binding and its ability to reveal very low occupancy of opiate receptors in brain.
The in vitro plasma protein binding and distribution in blood of fentanyl and three analogues were studied in rats, dogs and healthy volunteers. In human plasma, 84.4% of fentanyl was bound, 92.5% of sufentanil, 92.1% of alfentanil and 93.6% of lofentanil. Plasma protein binding of the four analgesics was independent of their concentration over the whole therapeutic range. Plasma protein binding of alfentanil was much less pH dependent than that of the three other analgesics. Attention was drawn to the possible contribution of the "acute phase" protein alpha 1-acid glycoprotein (alpha 1-AGP), of lipoproteins and of blood cells to the binding of fentanyl and its analogues in blood.
The influence of the pH of the incubation medium on the cellular accumulation of tritiated fentanyl, lofentanil, and alfentanil was investigated in isolated guinea pig atria. Fentanyl and lofentanil accumulated in atrial tissue up to about 30- and 50-fold, respectively. The amount of drug bound when equilibrium was attained was found to be dependent upon the pH of the medium. By plotting binding equilibria v. pH of the bath, curves were obtained which resembled titration curves. Half-maximal binding was attained at pH values close to the pKa values of fentanyl and lofentanil. Alfentanil was found to accumulate less. The uptake by the tissue was strongly proportional to the extracellular concentration. Atria equilibrated with fentanyl at pH 8.5 released the compound rapidly when exposed to a pH of 7.0, even in the continuous presence of fentanyl in the bath. The consequences of the findings for in vivo conditions are discussed with respect to a possible augmentation of the actions of fentanyl by respiratory acidosis.
来源:Hazardous Substances Data Bank (HSDB)
文献信息
NASAL DRUG PRODUCTS AND METHODS OF THEIR USE
申请人：Adapt Pharma Limited
公开号：US20170071851A1
公开（公告）日：2017-03-16
Drug products adapted for nasal delivery, comprising a pre-primed device filled with a pharmaceutical composition comprising an opioid receptor antagonist, are provided. Methods of treating opioid overdose or its symptoms with the inventive drug products are also provided.
