Ritalin Essays - Methylphenidate, , Term Papers

Ritalin Ritalin The Babysitter of the 90's 07/03/2000 Prepared for Nursing 2116 by Tracey Hardin Ritalin (Methylphenidate) is a mild CNS stimulant. In medicine, Ritalin's primary use is treatment of Attention Deficit /Hyperactive Disorder (ADHD). The mode of action in humans is not completely understood, but Ritalin presumably activates the arousal system of the brain stem and the cortex to produce its stimulant effect. Recently, the frequency of diagnosis for ADHD has increased dramatically. More children and an increasing number of adults are being diagnosed with ADHD. According to the Drug Enforcement Agency (DEA) (Bailey 1995), prescriptions for Ritalin have increased more than 600% in the past five years. Ritalin has a long history of controversy regarding side effects and potential for abuse, however it greatly benefits those with ADHD. Ritalin (Methylphenidate) is manufactured by CIBA-Geigy Corporation. It is supplied in 5 mg., 10 mg., and 20 mg. tablets, and in a sustained release form, Ritalin SR, in 20 mg. tablets. It is readily water soluble and is intended for oral use. It is a Schedule II Controlled Substance under both the Federal and Vermont Controlled Substance Acts. Ritalin is primarily used in the treatment of Attention Deficit/Hyperactive Disorder (ADHD) (Bailey 1995). ADHD is a condition most likely based in an inefficiency and inadequacy of Dopamine and Norepinephrine hormone availability, typically occurring when a person with ADHD tries to concentrate. Ritalin improves the efficiency of the hormones Dopamine and Norepinephrine, increasing the resources for memory, focus, concentration and attention (Clark 1996). Ritalin has been used for more than 30 years to treat ADHD. Nervousness and insomnia are the most common adverse reactions reported, but are usually controlled by reducing dosage or omitting the afternoon or evening dose. Decreased appetite is also common but usually transient (Long 1996). According to Clark (1996), children, adolescents and adults diagnosed with ADHD usually report the following effects when successfully treated with Ritalin: Improved concentration Better focus Improved ability to complete their work Improved intensity of attention and longer attention span Reduced distractibility Reduced impulsivity Reduced restlessness and overactivity Improved patience More elaborate expressive vocabulary Better written expression and handwriting (especially in children) An improved sense of alertness Improved memory for visual as well as auditory stimuli Ritalin exhibits pharmacological activity similar to that of amphetamines. Ritalin's exact mechanism of action in the CNS is not fully understood, but the primary sites of activity appear to be in the cerebral cortex and the subcortical structures including the thalamus. Ritalin blocks the reuptake mechanism present in dopaminergic neurons. As a result, sympathomimetic activity in the central nervous system and in the peripheral nervous system increases. Ritalin-induced CNS stimulation produces a decreased sense of fatigue, an increase in motor activity and mental alertness, mild euphoria, and brighter spirits. In the PNS, the actions of Ritalin are minimal at therapeutic doses (Clinical Pharmacology Online 1997). Ritalin is the quickest of all oral ADHD stimulant medications in onset of action: it starts to achieve benefit in 20 - 30 minutes after administration, and is most effective during the upward slope' and peak serum levels. Ritalin's effect is brief: Most people experience 2-3 hours of benefit, but after 3 hours, benefits drop off rapidly. Some individuals, especially children, may obtain 4 or even 5 hours of positive effect (Clark 1996). Recently, there has been a dramatic upsurge of interest in using stimulants (mainly Ritalin) for children and adults for the increasingly popular diagnosis of ADHD. According to Persky (1996), the high frequency of the diagnosis of ADHD is a uniquely American phenomenon. Children and adults are now under greater pressure to perform and to do well academically or in the workplace. The chilling message in school and at work is Perform or Else. Because of this high intensity atmosphere, the use of Ritalin has become attractive. This has resulted in an acute epidemic of ADHD and the treatment of choice is Ritalin (Persky 1996). For example, after education reforms spearheaded by Ross Perot in Texas in 1984, Ritalin use in the state doubled. One Texas mother says she is being hounded by teachers to put her two boys on Ritalin against their psychologist's advice. Another mother says she had to ask a school board member to intervene when teachers at her child's school also pressed for

Transition Metal Colors in Aqueous Solution

Transition Metal Colors in Aqueous Solution The transition metals form colored ions, complexes, and compounds in aqueous solution. The characteristic colors are helpful when performing a qualitative analysis to identify the composition of a sample. The colors also reflect interesting chemistry that occurs in transition metals. Transition Metals and Colored Complexes A transition metal is one that forms stable ions that have incompletely filled d orbitals. By this definition, technically not all of the d block elements of the periodic table are transition metals. For example, zinc and scandium arent transition metals by this definition because Zn2 has a full d level, while Sc3 has no d electrons. A typical transition metal has more than one possible oxidation state because it has a partially filled d orbital. When transition metals bond to one more neutral or negatively charged nonmetal species (ligands), they form what are called transition metal complexes. Another way to look at a complex ion is as a chemical species with a metal ion at the center and other ions or molecules surrounding it. The ligand attaches to the central ion by dative covalent or coordinate bond. Examples of common ligands include water, chloride ions, and ammonia. Energy Gap When a complex forms, the shape of the d orbital changes because some are nearer the ligand than others: Some d orbitals move into a higher energy state than before, while others move to a lower energy state. This forms an energy gap. Electrons can absorb a photon of light and move from a lower energy state into a higher state. The wavelength of the photon that is absorbed depends on the size of the energy gap. (This is why splitting of s and p orbitals, while it occurs, does not produce colored complexes. Those gaps would absorb ultraviolet light and not affect the color in the visible spectrum.) Unabsorbed wavelengths of light pass through a complex. Some light is also reflected back from a molecule. The combination of absorption, reflection, and transmission results in the apparent colors of the complexes. Transition Metals May have More Than One Color Different elements may produce different colors from each other. Also, different charges of one transition metal can result in different colors. Another factor is the chemical composition of the ligand. The same charge on a metal ion may produce a different color depending on the ligand it binds. Color of Transition Metal Ions in Aqueous Solution The colors of a transition metal ion depend on its conditions in a chemical solution, but some colors are good to know (especially if youre taking AP Chemistry): Transition Metal Ion Color Co2+ pink Cu2+ blue-green Fe2+ olive green Ni2+ bright green Fe3+ brown to yellow CrO42- orange Cr2O72- yellow Ti3+ purple Cr3+ violet Mn2+ pale pink Zn2+ colorless A related phenomenon is the emission spectra of transition metal salts, used to identify them  in  the  flame test.