Methylphenidate stimulant effect

Sellings LHL, Clarke PBS (2003) Segregation of amphetamine reward and locomotor stimulation between nucleus accumbens medial medial shell and core, J Neurosci 23 6295-6303 Sellings EH, McQuade EE, Clarke PB (2006) Characterization of dopamine-dependent rewarding and locomotor stimulant effects of intravenously-administered methylphenidate in rats. Neuroscience 141 1457-1468... 

A frequently used test to assess the effect of psychostimulants is the CPT. Methylphenidate at doses of around 0.3mg/kg usually improves performance, Le. reduces the number of errors, on the CPT whereas the effects of d-amphetamine (at doses between 5 and 20 mg) and pemoline (10 60mg) appear to be less reliable (Riccio et al., 2001). The stimulating effect of caffeine in various areas of performance is of shorter duration than that of... 

SYMPATHOMIMETICS CYTOTOXICS -PROCARBAZINE Co-administration of ephedrine, metaraminol, methylphenidate, phenylephrine or pseudoephedrine (including nasal and ophthalmic solutions) with procarbazine may cause a prolongation and t intensity of the cardiac stimulant effects and effects on BP, which may lead to headache, arrhythmias, hypertensive or hyperpyretic crisis The metabolism of sympathomimetics is impaired due to an inhibition of MAO It is recommended that sympathomimetics not be administered during and within 14 days of stopping procarbazine. Do not use any OTC nasal decongestants (sprays or oral preparations) or asthma relief agents without consulting the pharmacist/doctor... 

During the early 1990s, reports of abuse of methylphenidate began to appear. Nonmedical use of the drug for its stimulant effects impelled the U.S. Drug Enforcement Administration (DEA) to regulate the manufacture, distribution, and prescription of methylphenidate. Because methylphenidate is related to amphetamine, it can be addictive and result in physical and psychological dependence, see also Neurochemistry Neurotransmitters Pharmaceutical Chemistry. 

ADHD, usually first evident in childhood, is characterized by excessive motor activity, difficulty in sustaining attention, and impulsiveness. A variety of stimulant drugs have been utilized in the treatment of ADHD, and they are particularly indicated in mode rate-to-seve re cases. Methylphenidate is effective in children with ADHD and is the most common intervention treatment may start with a dose of 5 mg in the morning and at lunch, increasing gradually over a period of weeks depending on the response as judged by parents, teachers, and the clinician. 

Drug interactions for the RIMAs include interaction with SSRI antidepressants, which can cause the 5-HT syndrome (see the discussion of SSRIs). The effect of stimulant drugs, such as methylphenidate and dextroamphetamine (used to treat ADHD), may be increased. Some over-the-counter cold and hay fever decongestants (i.e., sympathomimetic amines) can have increased stimulant effects. Selegiline, a selective MAO-B used for Parkinson s disease, should not be used concurrently with the RIMAs. Unlike the irreversible MAOIs, no significant interactions with foods occur, because the selective inhibition of MAO-Adoes not stop the metabolism of tyramine. The RIMAs must not be taken concurrently with a nonreversible MAOI. 

In the first case, the stimulant effect of the methylphenidate was thought to have antagonised the sedative effect of the midazolam and ketamine. The methylphenidate may also have delayed the absorption of the oral drugs. In addition, methylphenidate may inhibit liver microsomal enzymes and could therefore possibly delay elimination of both ketamine and midazolam so that hazardous plasma concentrations could develop. However, the study did not find evidence of these effects. 

The piperidino derivative, SU-19789B (20>. produced a stimulant effect in mice and rats similar to that of methyl-phenidate however, (20) did not change the duration of sleep induced by hexobarbital in mice (methylphenidate prolonged such sleep). Neurophysiological studies in the cat suggested a peripheral site of action for this compound. ... 

Pemoline [2152-34-3] (24), stmcturally dissimilar to amphetamine or methylphenidate, appears to share the CNS-stimulating properties. As a consequence, pemoline is employed in the treatment of ADHD and of narcolepsy. There are several other compounds that are stmcturally related to amphetamines, although not as potent and, presumably, without as much abuse potential. These compounds also have anorexic effects and are used to treat obesity. Some of the compounds available are phentermine [122-09-8] fenfluramine [458-24-2] and an agent that is available over-the-counter, phenylpropanolamine [1483815-4] (26). 

At low doses, both psychostimulants could theoretically stimulate tonic, extracellular levels of monoamines, and the small increase in steady state levels would produce feedback inhibition of further release by stimulating presynaptic autoreceptors. While this mechanism is clearly an important one for the normal regulation of monoamine neurotransmission, there is no direct evidence to support the notion that the doses used clinically to treat ADHD are low enough to have primarily presynaptic effects. However, alterations in phasic dopamine release could produce net reductions in dopamine release under putatively altered tonic dopaminergic conditions that might occur in ADHD and that might explain the beneficial effects of methylphenidate in ADHD. 

Psychostimulants (e.g., methylphenidate and dextroamphetamine with or without amphetamine) are the most effective agents in treating ADHD. Once the diagnosis of ADHD has been made, a stimulant medication should be used first line in treating ADHD (Fig. 39-1). Stimulants are safe and effective, with a response rate of 70% to 90% in patients with ADHD.3,13,14 Generally, a trial of at least 3 months on a stimulant is appropriate, and this includes dose titration to response... 

Initial response to short-acting stimulant formulations (e.g., methylphenidate and dextroamphetamine) is seen within 30 minutes and can last for 4 to 6 hours.13,14 This short duration of effect frequently requires that short-acting stimulant formulations be dosed at least twice daily, thus increasing the chance of missed doses and non-compliance. Further, patients using any stimulant formulation but especially shortacting formulations can experience a rebound effect of ADHD symptoms as the stimulant wears off.14... 

The answer is a. (Hardman, p 22L Katzang, p L3L) Methylphenidate is similar to amphetamine and acts as a CN5 stimulant, with more pronounced effects on mental than on motor activities. It is effective in the treatment of narcolepsy and attention-deficit hyperactivity disorders. 

Methylphenidate is now the most widely used of the stimulants. It has a well-established record of safety and tolerability and has been used in children throughout the school years and in adults as well. In preschool children, the effects of methylphenidate can vary. 

Dextroamphetamine (Dexedrine). Dextroamphetamine is the second most widely used stimulant and the most commonly used amphetamine in the United States. It is about twice as potent as methylphenidate and should be initiated in the treatment of ADHD at 2.5 mg taken twice daily with breakfast and lunch. Like other stimulants, the benefits of dextroamphetamine can be seen almost immediately. With weekly visits while starting treatment, the dose can be increased in 2.5-5 mg increments until the effective dose is found. Because dextroamphetamine is also slightly longer acting than methylphenidate, patients may be less likely to need an evening dose. If an after-school dose is used, then like methylphenidate it should be 25-50% of the daytime dose. 

Starting Treatment in Adults with ADHD. Beginning treatment of an adult is not significantly different from doing so in a child. The stimulants and atomoxetine remain the most effective medications. Methylphenidate, dextroamphetamine, and Adderall appear to be equally effective in group trials, but individuals may respond preferentially to one medication or the other. 

Methylphenidate (Ritalin, Concerta, Focalin). Methylphenidate was introduced in the late 1950s and is now the most widely used prescription stimulant. It was first used to treat ADHD in children but is also effective for narcolepsy. Like dextroamphetamine, methylphenidate should be started at 5 mg per dose given two to three times each day with meals. The average effective dose is 20-30 mg/day, but some patients require as much as 60 mg/day. The benefit of methylphenidate should also be apparent on the first day or so, and the dose can be increased every 5-7 days as needed. Focalin dosing is approximately half that of methylphenidate. 

Stimulants. Methylphenidate (Ritalin) and dextroamphetamine (Dexedrine) are the most widely used and perhaps the most effective medications when treating post-TBI apathy. They act by enhancing the activity of dopaminergic, noradrenergic and, to a certain extent, serotonergic brain systems. Stimulants act quickly to relieve the core symptoms of apathy, and they may also improve the impairments in attention and short-term memory that often follow TBl. Please refer to Chapter 8 for more information about the stimulants. 

CNS stimulants can be classified as Psychomotor stimulants compounds that display a stimulatory effect primarily on brain functions and which activate mental and physical activity of the organism. They are made up of methylxanthines (caffeine, theophylline, pentoxifyllin), amphetamines (dextroamphetamine, methamphetamine), and also methylphenidate and pemoline. Respiratory stimulants or analeptics compounds, which cause certain activations of mental and physical activity of the organism, and primarily excite the vasomotor and respiratory centers of the medulla (doxapram, almitrine).Drwgi that suppress appetite or anorectics drags that activate mental and physical activity of the organism, but primarily accentuate the excitatory center of satiation in the hypothalamus (phentermine, diethylpropion).In order to increase mental capability, nootropics — drugs that increase the functional state of the brain — are sometimes used, the effect of which is associated with blood flow and metabolism of the brain. 

Methylphenidate is a CNS stimulant similar to amphetamine however, in usual doses it has a more expressed action on mental activity rather than physical or motor activity. In therapeutic doses it does not raise blood pressure, respiratory rate, or increase heart rate. All of these effects as well as a number of others are associated with general excitement of the CNS. Tremor, tachycardia, hyperpyrexia, and a state of confusion can result from using large doses. It is used in treating moderate depression and apathetic conditions, and also as an adjuvant drug for treating attention deficit disorder in children.Synonyms of this dmg are meridil, ritalin, and others. 

---