Use and management of medications for children diagnosed with Attention Deficit Hyperactivity Disorder (ADHD)

Focus on Exceptional Children, Jan 2001 by Kollins, Scott H, Barkley, Russell A, DuPaul, George J

Peak Effects

The final basic principle of psychopharmacology that is important for parents and teachers to understand is that drugs (especially the stimulants; see Table 1) often exert their optimal clinical (i.e., behavior-improving) effects at a certain point after administration. This time point often is referred to as the time of peak effects and, because it is related to the concept of half-life, varies across drugs. For example, the peak effects for standard formulations of Ritalin usually occur 1.5-2 hours after administration. This means that, although beneficial effects may be observed sooner, the maximal effect of the drug is not likely to occur until later and the effects after that time may begin to diminish.

Sometimes the way a drug is administered influences the peak effects. For example, Ritalin is available in sustained release formulations that may influence the time at which peak effects are observed and the length of time the drug remains clinically active (Birmaher, Greenhill, Cooper, Fried, & Maminski, 1989; Pelham, Sturges, et al., 1987).

Understanding when different drugs exert their peak effects can provide valuable information to parents and teachers who are administering or overseeing use of the drug. For example, a child whose attentional and concentration deficits are particularly problematic in math class, just before lunch, might not benefit from a dose of standard Ritalin administered 4 or 5 hours earlier at breakfast, as the peak effects of the medication likely will occur 1.5 to 2 hours after administration.

An important caveat to the above principles of psychopharmacology is that the patterns of side effects, doseresponse functions, half-life, and peak effects are not uniform across individuals. In fact, considerable variation exists in these concepts, even within the same individual. For example, as noted previously, the specific behavior under study influences the relation between the amount of drug and the extent of behavior change (the dose-response relation). Similarly, factors such as presence of other prescription or over-the-counter medications, recent meals, or sleep patterns might all influence the half-life or peak effects, or both, of drugs within the same child.

These characteristics of drug effects underscore two important facts that will be discussed below.

1. The only way to confidently determine the specific effects of a drug for any given child is to conduct a carefully controlled drug assessment.

2. Generally speaking, drugs affect individuals in different ways.

This principle of psychopharmacology is important, as it can influence the expectations of important individuals who interact with a medicated child, such as parents and teachers. For example, a teacher who observed one child in his or her class respond well following a treatment regimen with Ritalin might not see the same positive effects in another child prescribed the same medication.

Drugs used to treat ADHD

The drugs used most frequently to treat ADHD in children and adolescents fall into three general categories: stimulants, antidepressants, and antihypertensive agents. We will discuss each of these next, including a description of the drug class, identification of specific drugs shown to be effective for ADHD, recommended doses, contraindications for use, and common side effects.