Naltrexone

Naltrexone is oral opiate receptor antagonist. Naltrexone is derived from thebaine and is extremely similar in structure to oxymorphone. Like parenteral naloxone, Naltrexone is a pure antagonist (i.e., agonist actions are not apparent) but has better oral bioavailability and much longer duration of action than naloxone. Clinically, Naltrexone is used to help maintain an opiate-free state in patients who are known opiate abusers. It was approved by the FDA in 1984, and for the treatment of alcoholism, it was approved in january 17, 1995. Like naloxone, Naltrexone is a competitive antagonist at opiate receptor subtypes µ, , and Like naloxone, Naltrexone is a competitive antagonist at opiate receptor subtypes µ, ? and d. It can either prevent or displace opiate agonists from binding at these receptors. It does not antagonize the effects of non-opiates such as cocaine, ethanol, amphetamines, barbiturates, or benzodiazepines.

Brands
NULIFY E-TRACK TREXAN
Adult Dose
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Neonatal
Paedriatic
Dose: Safety not established
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Characteristics
. It is of Synthetic origin and belongs to Cyclopropane. It belongs to OPIATE antagonist pharmacological group on the basis of mechanism of action and also classified in Antidotes pharmacological group.The Molecular Weight of Naltrexone is 341.40. Its pKa is 8.13.
Contraindications
Naltrexone is contraindicated in conditions like Liver diseases,Opioid dependence.
Effects
The severe or irreversible adverse effects of Naltrexone, which give rise to further complications include Hepatic damage, Thrombocytopenic purpura.The signs and symptoms that are produced after the acute overdosage of Naltrexone include Liver dysfunction.The symptomatic adverse reactions produced by Naltrexone are more or less tolerable and if they become severe, they can be treated symptomatically, these include Tiredness, Headache, Diarrhea, Anxiety, Restlessness, Abdominal cramps, Skin rashes, GI adverse effects, Somnolence, Nausea and vomiting, Muscle aching, Skin rashes.
Indications
Naltrexone is primarily indicated in conditions like Adjunct to prevent relapse, Amenorrhoea, Heart failure, Induction of ovulation, Opioid addiction, Supraventricular arrhythmias (particularly atrial fibrillation), and can also be given in adjunctive therapy as an alternative drug of choice in Alcohol dependence, Appetite suppresser, Mental illness, Obesity, Pulmonary disease.
Interactions
Naltrexone is known to interact with other drugs, the details of drug interactions is as follows:DrugDetailsSeverityOnsetManagementAcamprosate CalciumMethyltestosteroneCoadministration of naltrexone with other agents known to induce hepatotoxicity may potentiate the risk of liver injury. Naltrexone, especially in larger than recommended doses (more than 50 mg/day), has been associated with hepatocellular injury, hepatitis, and elevations in liver transaminases and bilirubin.ModerateConcomitant use is generally not recommended unless the potential benefit outweighs the risk of hepatotoxicity. Periodic monitoring of hepatic function is advisable.OxandroloneCoadministration of naltrexone with other agents known to induce hepatotoxicity may potentiate the risk of liver injury. Naltrexone, especially in larger than recommended doses (more than 50 mg/day), has been associated with hepatocellular injury, hepatitis, and elevations in liver transaminases and bilirubin.ModerateConcomitant use is generally not recommended unless the potential benefit outweighs the risk of hepatotoxicity. Periodic monitoring of hepatic function is advisable.OxymetholoneCoadministration of naltrexone with other agents known to induce hepatotoxicity may potentiate the risk of liver injury. Naltrexone, especially in larger than recommended doses (more than 50 mg/day), has been associated with hepatocellular injury, hepatitis, and elevations in liver transaminases and bilirubin.ModerateConcomitant use is generally not recommended unless the potential benefit outweighs the risk of hepatotoxicity. Periodic monitoring of hepatic function is advisable.SulpirideThioridazine (HCl)Lethargy and somnolence have been reported following concurrent use.Moderate These interactions are sometimes beneficial and sometimes may pose threats to life. Always consult your physician for the change of dose regimen or an alternative drug of choice that may strictly be required.
Interfrence
Abnormal LFTs
Risks
Drug should not be given to Paediatrics, Pregnant Mothers, patients suffering from Liver Malfunction, Geriatrics, and Neonates.If prescribing authority justifies the benefits of the drug against the possible damages he/she should reevaluate them and consult the reference material and previous studies.
Storage
Tab Store Below 40°C. Protect from Sunlight and Heat.
Warnings
Naltrexone should be used only if clearly needed during pregnancy or lactation. It should be used with caution in patients with any pre-existing liver disease or if have any allergy. This must not be used in persons dependent on narcotics. Should be given with cuation to renal pateints.
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