Psychostimulants

Commercially available psychostimulants include:

** methylphenidate (Ritalin, Methylin, Metadate)

** D-amphetamine (Dexedrine, Dextrostat, Spansule)

** D,L-amphetamine (Adderall)

** magnesium pemoline (Cylert, PemADD)

These sympathomimetic compounds are structurally dissimilar but share a phenylethylamine backbone with endogenous catecholamines (eg, dopamine and norepinephrine). The mechanism of action of psychostimulants is thought to be re-uptake blockade of catecholamines into presynaptic nerve endings, thereby preventing their degradation by monoamine oxidase. In addition, amphetamine compounds appear to cause retrograde release of catecholamines through the transporter as well as other actions on the vesicular storage of catecholamines.^[11]

The mechanisms are “thought to” block natural occuring reactions in the body.  Although … they aren’t really sure …

Table 2. Psychostimulants Used in the Treatment of ADHD

Psychostimulant efficacy. An extensive body of literature has clearly documented the short-term efficacy of methylphenidate treatment, mostly in latency-age Caucasian boys.^[12] The literature describing the efficacy of stimulants on girls, ethnic minorities, and patients of other ages is more limited. Recently, a controlled study of stimulants in girls with ADHD documented substantial improvement of ADHD, matching that seen in boys.^[13] While most studies have examined only short-term response, there are a growing number of long-term studies documenting the persistence of stimulant-associated improvements.^[10,14-16]

Because our children are the lab-rats for these studies, without parental knowledge.

The few studies of stimulants in adolescents reported rates of response highly consistent with those seen in latency-age children.^[17-25] In addition, the few studies on preschoolers appear to indicate that young children respond almost as well to stimulant therapy; however, there is a suggestion that ADHD preschoolers may be somewhat more treatment refractory.^[25-30] The literature clearly documents that treatment with stimulants improves not only abnormal behaviors associated with ADHD but also self-esteem and cognitive, social, and family function. This finding supports the importance of treating ADHD patients beyond school or work hours to include evenings, weekends, and vacations. Recent controlled clinical trials documented the efficacy of methylphenidate, Adderall, and pemoline in adults with ADHD.^[31-33] These trials documented a highly clinically and statistically significant separation from placebo, and the magnitude of the effects was consistent with trials of latency age children.

Stimulants have been demonstrated to improve cognitive function in children with ADHD as measured by tests of vigilance, impulsivity, reaction time, short-term memory, and learning of verbal and nonverbal material.^[34-36] These stimulant-associated improvements also have been demonstrated in a simulated classroom paradigm.^[37,38] However, it appears that the primary deficits in ADHD are those of regulation of cognitive function and executive deficits,^[39,40] cognitive deficits that are not as amenable to measurement by objective tests. In individual children, the more prominent behavioral effects of stimulants have been more useful in clinically monitoring stimulant treatment than the cognitive tests per se.

While originally it was thought that cognition and behavior were responsive to different doses of stimulants,^[41] recent studies indicate that both behavior and cognitive performance improve with stimulant treatment in a dose-dependent fashion.^[35,42-48] Also, despite previous concerns, doses that improve behavior rarely constrict attention or cause “overfocusing.”^[49,50]

Psychostimulant safety. Common side effects of psychostimulants include appetite suppression and sleep disturbances. Usually, sleep disturbances can be alleviated by lowering late afternoon doses or adding clonidine or other medications.^[51,52]

Just what your child needs … more drugs to cover up the effects of more drugs.  These completely foreign substances to the human body MUST be making them healthier …

Occasionally, mild increases in pulse and blood pressure of unclear clinical significance have been observed.^[53]

“Unclear clinical significance?”  Apparently, a rise in pulse and blood pressure in children is not really clinically significant … we guess.  However, if your child presented with high blood pressure and increased pulse as a main complaint in a doctor’s office, would it be clinically significant then?  Maybe there are more drugs you can take for this “unclear” side effect!

Stimulant-associated toxic psychosis appears to be rare but resembles a toxic phenomenon (eg, visual hallucinosis) and not a schizotypal-like exacerbation of psychotic symptoms.

Since it is rare … why not overlook this minor detail that your child may be able to sit in a chair for a longer period … but now they see the flowers on your wallpaper dancing around the room.

Administration of pemoline has been associated with hypersensitivity reactions involving the liver accompanied by elevations in liver function tests (SGOT and SGPT) after several months of treatment.

Could this be because your body does not know what to do with these foreign substances and it therefore starts sending important organs into a state of dysfunction?  This is probably “unclear” as well.

The US Food and Drug Administration (FDA) recommends monitoring liver function every 2 weeks;

What better way to make money than to require bi-monthly visits to your physician?

however, it is also advisable to educate parents about the warning symptoms of hepatitis. Such symptoms include stomach pain, gastrointestinal distress, and discoloration of urine (darker) or stool (lighter).

While stimulants are potentially abusable, a study has shown that the most commonly abused substance in ADHD adolescents and adults is marijuana and not stimulants.^[54]

Let’s see … your child is taking stimulants on a daily basis anyway, but since they are prescribed, it is okay to use that drug and therefore not considered abusive.  However, if your child is smoking dope everyday, and it is not prescribed … this is the only problem in this picture.

Another study suggests that stimulant treatment substantially reduces the risk for substance abuse generated by ADHD cognitive and behavioral impairments.^[55] However, appropriate education and monitoring is crucial to the safe prescription of psychostimulants in adolescents and adults.

While ADHD appears to be a major factor in the impairment attributed to Tourette’s syndrome,^[56] it is unclear whether the presence of tics has a general impact on the course of ADHD. Our group examined this issue in an ongoing prospective study of ADHD boys.^[57] We found that ADHD boys had more tic disorders at baseline and follow-up than controls. However, tic disorders had little impact on the psychosocial functioning of ADHD boys, and stimulant treatment was not associated with increased rates, severity, or persistence of tic disorders. Recent studies have demonstrated that stimulants are effective in many children with ADHD and tic disorders.^[58-60] Nonetheless, it seems prudent to weigh the risks and benefits of individual cases and to conduct appropriate discussions with the patient and family about the risks and benefits of the use of stimulants in individuals with ADHD and tics.

Concerns about the effects of long-term administration of stimulants on growth persist. Stimulants routinely produce anorexia and weight loss, but their effect on growth in height is much less certain. Initial reports suggested that there was a persistent stimulant-associated decrease in growth in height in children^[61,62]; however, other reports have failed to substantiate this claim.^[63,64] Moreover, several studies showed that ultimate height appears to be unaffected if treatment is discontinued in adolescence.^[65] A recent study suggested that deficits in growth in height may be transient maturational delays associated with ADHD rather than with the medication for ADHD.^[66] If confirmed, this finding would not support the common practice of drug holidays in ADHD children. However, it seems prudent to initiate drug holidays or alternative treatment in children suspected of stimulant-associated growth deficits. This recommendation should be carefully weighed against the risk for exacerbation of symptoms due to drug discontinuation. A transient behavioral deterioration can occur upon the abrupt discontinuation of stimulant medications in some children. The prevalence of this phenomenon and the etiology are unclear. Rebound phenomena can also occur in some children between doses, creating an uneven, often disturbing clinical course. In those cases, consideration should be given to alternative treatments.

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