Ask the Experts

How Does ADHD Medication Work? Your First Questions Answered.

Wondering which ADHD medication to try or what dose is right? Dr. William Dodson answers common questions about the stimulants and non-stimulants used to treat ADHD.

What you need to know about ADHD medications

Everyone gets a little nervous when the doctor reaches for his prescription pad and rips off a sheet to prescribe ADHD medication. So many questions, and so little time.

How long will you have to take it? How will you know that it is working? Are ADHD medicines safe? What about side effects? Will you feel like a zombie, or will it put a spring in your step and give you the ability to manage symptoms? How does ADHD medication work, anyway? Asking those questions about your child raises your worries to a serious level. Here are straightforward answers — so settle back and be informed.

Will Meds Work for Me?

How can you know, or at what point do you know, that you are part of the 20 percent of people for whom meds don’t work?

The first-line stimulant medications for ADHD are among the most effective treatments in all of medicine. Unfortunately, as many as one in five people do not respond to the two standard stimulants, methylphenidate and amphetamine.

We measure effectiveness through a statistical calculation called effect size. Just about every medicine falls within an effect size of 0.4 (barely but consistently detectable) to 1.0 (robust therapeutic response). The effect size of the optimal molecule and optimal dose of stimulant can be as high as 2.1. Simply put, the benefits of medication will be nothing short of life-changing.

The most common problem in achieving the optimal dose is that physicians stop increasing the dosage at the first sign of positive benefit in their patients, fearing that the development of side effects at higher doses will cause the patient to stop taking the medication altogether.

If you have tried both methylphenidate and amphetamine at adequate dosages, and have seen neither benefits nor side effects, it is possible that you are in the 3 percent of people who just do not absorb these medications orally. The formulation to try at this point is the transdermal delivery system, Daytrana,* also known as the patch.

ODD and ADHD

My son has been diagnosed with ADHD, but he seems to have oppositional defiant disorder (ODD). Will stimulants help ODD?

Oppositional defiant disorder (ODD) coexists with ADHD in up to 40 percent of children. ODD is very rare in people who do not have ADHD. Medication won’t help specifically with ODD, but it can help your child reign in ADHD behaviors and feel more in control, which can be useful for accessing behavioral therapy techniques that have been proven effective for ODD. In these cases, the medication of choice for the treatment of ODD has been either methylphenidate or amphetamine.

Having ODD, a child is hardwired to defeat the authority figure — typically, a parent. I find that kids with ODD tuck the ADHD medication in their cheek and spit it out later. That’s why I prefer the amphetamine Vyvanse, which can be dissolved in water. A liquid form of methylphenidate, Quillivant XR, is another way to get medication into a recalcitrant child.

The Problems with Vitamin C

I heard that vitamin C affects stimulant medication adversely.

You shouldn’t take ascorbic acid or vitamin C an hour before and after you take medication. ADHD stimulants are strongly alkaline and cannot be absorbed into the bloodstream if these organic acids are present at the same time. High doses of vitamin C (1000 mg.), in pill or juice form, can also accelerate the excretion of amphetamine in the urine and act like an “off” switch on the med.

Are There Withdrawal Symptoms?

Will you notice withdrawal side effects from Concerta after missing several doses? Also, is a flat, dull expression common?

There is little cumulative effect from the stimulant medications. If you stop taking them, the benefits dissipate quickly, usually in a matter of hours rather than days. Luckily, these medications work for a lifetime without the development of tolerance, but they need to be taken reasonably consistently in order to get full benefits.

A flat, dull, unemotional expression, known as “Zombie Syndrome,” almost always suggests that the medication dose is too high. Talk with your doctor about lowering the dosage.

When Do Side Effects Decrease?

Don’t some of the initial side effects from ADHD medication smooth out after a short period? Is there an adjustment period? How long should I endure side effects before I change meds?

Most side effects of stimulant medications should resolve in three to five days (with the exception of appetite suppression). Side effects that the patient finds intolerable, or those that last longer than three to five days, warrant a call to your clinician. It is vital that neither the patient nor the parent has a bad experience when starting ADHD medication in order to ensure long-term use and success. As a result, I always recommend that side effects be addressed and managed promptly.

When Do Meds Start Working?

How long does it take for an ADHD medication to have an effect? Is there an adjustment period, or do you know right away that it is a good option for managing symptoms?

There are two classes of medication for ADHD that treat symptoms: stimulants and non-stimulants.

The stimulant medications are effective as soon as they cross the blood-brain barrier, which takes 45 to 60 minutes. Consequently, in adults, it is possible to change the dose of stimulant medication every day to determine the optimal molecule and dose in less than a week. Schoolchildren, however, often lack the ability to tell the clinician how the medication is affecting their functioning and mood. For patients under the age of 15, the medication dose can be raised only once a week, to allow time for parents and teachers to assess the effect on symptoms.

The non-stimulant medications, like Strattera, Wellbutrin, Intuniv (guanfacine) and Kapvay (clonidine), are different. It often takes five to seven days after a dosage change to assess their benefits. As a result, it may take weeks to determine the optimal dose for these medications.

Losing Appetite

Do appetite suppression and weight loss suggest that my son is taking too high a dose of stimulant?

Not necessarily. Appetite suppression is the only side effect of stimulants that is not necessarily dose-related. More predictive of appetite suppression is the child who is already thin and a picky eater. You can try a lower dose of stimulant medication while you’re waiting for the next appointment with the pediatrician, but this usually results in loss of benefits for your child’s ADHD. Although no one likes to take several medications, additional medication is often required for children who have appetite suppression lasting longer than two months, or who continue to lose weight. Talk with your doctor.

ADHD and Mood Disorders

How do you treat ADHD in a person who has been diagnosed with a mood disorder?

Seventy percent of people with ADHD will have another major psychiatric condition at some time in their life. Mood disorders, dysthymia, and bipolar mood disorder are the most common conditions that coexist with ADHD. Most clinicians determine which condition is of most concern to the patient and proceed to treat that condition first. If the patient has suicidal thoughts, is unable to get out of bed, or is manic, the clinician will treat the mood disorder first and then reassess the symptoms of ADHD. Most clinicians will treat the ADHD first.

Time for a Higher Dosage?

How do you know when it is time to go up in dosage? Will increasing my medication’s dosage help — or is trying a new medication the way to go?

It is important to remember that with both stimulant medications and non-stimulants there is a “therapeutic window.” Doses that are too low or too high are ineffective. Since there is no factor that predicts either the optimal class of medication or the optimal dose in a given individual, dosing needs to be determined on the basis of target symptoms — determining the impairments the person is experiencing that they would like medication to manage. There are many things about ADHD that most people would like to keep — cleverness, high IQ, problem-solving ability, and relentless determination. Each person will have his or her own list.

Start with the lowest dose of stimulant medication, increasing it periodically. Continue to increase the dose, as long as the target symptoms improve without the development of side effects. At some point, however, you’ll increase the dose and won’t see further improvement. At that point, the previous dose is the optimal dose. When working with small children who have difficulty giving feedback, clinicians use scales (the Connor global index scale, for instance), which compare the patient to children without ADHD of the same gender and age.

 

*FDA is warning that permanent loss of skin color may occur with use of the Daytrana patch (methylphenidate transdermal system) for Attention Deficit Hyperactivity Disorder (ADHD). FDA added a new warning to the drug label to describe this skin condition, which is known as chemical leukoderma. See the FDA Drug Safety Communication for more information.

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