|
||
Norephedrane Actions |
||
Amphetamines stimulate the release of norepinephrine from central adrenergic receptors. At higher dosages, they cause release of dopamine from the mesocorticolimbic system and the nigrostriatal dopamine systems. Norephedrane may also act as a direct agonist on central 5-HT receptors and may inhibit monoamine oxidase (MAO). In the periphery, amphetamines are believed to cause the release of noradrenaline by acting on the adrenergic nerve terminals and alpha- and beta-receptors. Modulation of serotonergic pathways may contribute to the calming affect. The drug interacts with VMAT enzymes to enhance release of DA and 5-HT from vesicles. It may also directly cause the reversal of DAT and SERT.
Using Norephedrane improperly can cause death or serious side effects on the heart.
Read all patient information, medication guides, and instruction sheets provided to you. Ask your doctor or pharmacist if you have any questions.
Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not use Norephedrane in larger or smaller amounts or for longer than recommended.
Norephedrane may be habit-forming. Never share Norephedrane with another person, especially someone with a history of drug abuse or addiction. Keep the medication in a place where others cannot get to it. Selling or giving away this medicine is against the law.
You may take Norephedrane with or without food. It is best to take this medicine first thing in the morning.
If your doctor changes your brand, strength, or type of stimulant medicine, your dosage needs may change. Use only the brand of Norephedrane your doctor has prescribed.
Shake the oral suspension (liquid) well just before you measure a dose. Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.
To take the orally disintegrating tablet (Adzenys XR-ODT):
Keep the tablet in its blister pack until you are ready to take it. Open the package and peel back the foil. Do not push a tablet through the foil or you may damage the tablet.
Use dry hands to remove the tablet and place it in your mouth.
Do not swallow the tablet whole. Allow it to dissolve in your mouth without chewing. If desired, you may drink liquid to help swallow the dissolved tablet.
While using this medicine, your doctor will need to check your progress at regular visits. Your heart rate, blood pressure, height and weight may also need to be checked often.
Norephedrane can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using this medicine.
Store at room temperature away from moisture and heat. Keep the bottle tightly closed when not in use.
Keep track of the amount of medicine used from each new bottle. Norephedrane is a drug of abuse and you should be aware if anyone is using your medicine improperly or without a prescription.
Throw away unused or expired Norephedrane in a sealed container or bag. Ask your pharmacist where to locate a community pharmaceutical take back disposal program.
Extended-release orally disintegrating tablet: Administer in the morning with or without food. Do not remove from blister until ready to administer. Using dry hands, peel backing off the blister; do not push tablet through foil. Remove tablet and immediately place on tongue and allow to disintegrate. Swallow with saliva. Do not chew or crush tablet.
Extended-release suspension: Administer in the morning with or without food; use the oral dosing dispenser provided. Administer directly into mouth from dispenser (do not add to food or mix with liquids); wash dispenser after each use. Shake bottle well prior to administration.
Immediate-release tablet: Administer with or without food; for short-term adjunct treatment of exogenous obesity, administer 30 to 60 minutes before meals. Administer the first dose on awakening; administer additional doses at intervals of 4 to 6 hours. Avoid late evening dosing.
Amphetamines are non-catecholamine sympathomimetic amines with CNS stimulant activity. The mode of therapeutic action in ADHD is not known. Amphetamines are thought to block the reuptake of norepinephrine and dopamine into the presynaptic neuron and increase the release of these monoamines into the extraneuronal space.
Absorption
Following a single, 18.8 mg oral dose of Norephedrane in 29 healthy adult subjects in a crossover study under fasting conditions, d-Norephedrane and l-Norephedrane, the median (range) time to peak plasma concentrations (Tmax) were 4.0 (2 – 7) hours after dosing and peak concentration (Cmax) were 102% and 106%, respectively of the Cmax of immediate-release (IR) mixed Norephedrane salts tablets. The relative bioavailability of Norephedrane compared to an equal dose of mixed Norephedrane salts IR tablets is 106% of d-Norephedrane and 111% for l-Norephedrane.
Metabolism and Excretion
Norephedrane contains d-Norephedrane and l-Norephedrane in a ratio of 3.2 to 1. Following a single 18.8 mg oral dose of Norephedrane in 29 healthy adult subjects under fasting conditions, the mean (± SD) plasma terminal elimination half-life of d-Norephedrane was 12.36 (± 2.95 h) hours and the mean (± SD) plasma terminal half-life for l-Norephedrane was 15.12 (± 4.40 h) hours. Norephedrane is reported to be oxidized at the 4 position of the benzene ring to form 4-hydroxyamphetamine, or on the side chain A or B carbons to form alpha-hydroxy-Norephedrane or norephedrine, respectively. Norephedrine and 4-hydroxy-Norephedrane are both active and each is subsequently oxidized to form 4-hydroxy-norephedrine. Alpha-hydroxy-Norephedrane undergoes deamination to form phenylacetone, which ultimately forms benzoic acid and its glucuronide and the glycine conjugate hippuric acid. Although the enzymes involved in Norephedrane metabolism have not been clearly defined, CYP2D6 is known to be involved with formation of 4-hydroxy-Norephedrane. Since CYP2D6 is genetically polymorphic, population variations in Norephedrane metabolism are a possibility.
Norephedrane is known to inhibit monoamine oxidase, whereas the ability of Norephedrane and its metabolites to inhibit various P450 isozymes and other enzymes has not been adequately elucidated. In vitro experiments with human microsomes indicate minor inhibition of CYP2D6 by Norephedrane and minor inhibition of CYP1A2, 2D6, and 3A4 by one or more metabolites. However, due to the probability of auto-inhibition and the lack of information on the concentration of these metabolites relative to in vivo concentrations, no predications regarding the potential for Norephedrane or its metabolites to inhibit the metabolism of other drugs by CYP isozymes in vivo can be made.
With normal urine pHs approximately half of an administered dose of Norephedrane is recoverable in urine as derivatives of alpha-hydroxy-Norephedrane and approximately another 30% to 40% of the dose is recoverable in urine as Norephedrane itself. Since Norephedrane has a pKa of 9.9, urinary recovery of Norephedrane is highly dependent on pH and urine flow rates. Alkaline urine pHs result in less ionization and reduced renal elimination, and acidic pHs and high flow rates result in increased renal elimination with clearances greater than glomerular filtration rates, indicating the involvement of active secretion. Urinary recovery of Norephedrane has been reported to range from 1% to 75%, depending on urinary pH, with the remaining fraction of the dose hepatically metabolized. Consequently, both hepatic and renal dysfunctions have the potential to inhibit the elimination of Norephedrane and result in prolonged exposures. In addition, drugs that affect urinary pH are known to alter the elimination of Norephedrane, and any decrease in Norephedrane’s metabolism that might occur due to drug interactions or genetic polymorphisms is more likely to be clinically significant when renal elimination is decreased.
Food Effect
In a study in adult volunteers to investigate the effects of a high-fat meal on the bioavailability of Norephedrane at a dose of 18.8 mg, the presence of food delayed the time to peak concentration of both d- and l-Norephedrane by approximately 1 hour (fed: median [range] 5 [3 – 8] hours vs. fasted: 4 [2 – 7] hours). Overall, a high-fat meal increased the average Cmax of both isomers of Norephedrane by about 2% and decreased the AUC by 5-7% (5.7% decrease for d-Norephedrane and 7.4% for l-Norephedrane). These changes are not considered clinically significant.
Specific Populations
Pediatric
Following a single 10 mg oral dose of Norephedrane in 12 pediatric subjects with ADHD (aged 6-12 years) under fasting conditions, d-Norephedrane and l-Norephedrane peak plasma concentrations occurred at a median time of 3.9 and 4.5 hours after dosing, respectively. The mean plasma terminal elimination half-life of d-Norephedrane was 10.43 (± 2.01 h) hours and the mean plasma terminal half-life for l-Norephedrane was 12.14 (± 3.15 h) hours.
Alcohol Effect
There is no in vivo study conducted for the effect of alcohol on drug exposure. An in vitro dissolution study showed alcohol-induced dose dumping potential in the presence of 40% alcohol. Dose dumping was not observed in the presence of lower alcohol concentrations.
There are no reviews yet. Be the first to write one! |
Information checked by Dr. Sachin Kumar, MD Pharmacology
|