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The Common Side Effects of ADHD Medications

NOTE: This article consists of two parts. Part 1 serves as an introduction and outlines the side effects of stimulant medications; Part 2 lists the side effects of non-stimulant ADHD medicines. If you’re new to the topic, reading both articles is recommended. The article was medically reviewed by Dr. Pavlo Papach, a psychiatrist at Maale Hacarmel Mental Health Center in Israel. All the information is offered for educational purposes only.


ADHD medications help millions of adults enjoy more fulfilling daily lives. Still, determining the type and dose of medication for an individual typically requires some trial and error. The National Institute of Mental Health noted, “Sometimes several different medications or dosages must be tried before finding the right one that works for a particular person.” For those who are first trying ADHD medication or looking to adjust it, recognizing the side effects is crucial.

Why pay attention to side effects in the first place?

ADHD medications are not like antibiotics; they are rarely, if ever, prescribed for a short course. A better analogy for ADHD medicines are allergy pills because both only work while the active ingredient is still circulating in the system. The principal goal is to find a medication that effectively reduces ADHD symptoms and has minimal side effects, so an individual can comfortably take it every day.

The process of selecting ADHD medicines is gradual. The CHADD website describes it as follows: “Doctors will use a medication trial to figure out which medicine works best for each individual and at what dosage. The trial usually begins with a low dose that is gradually increased at 3-7 day intervals until clinical benefits are achieved.”

Not all ADHD medications are the same; they are divided into stimulants and non-stimulants. However, ADHDers take stimulants like Ritalin, Vyvanse, Adderall, or Focalin more often than other medicines. Stimulants are the first-line treatment for ADHD, meaning they are usually prescribed before trying any other medication.

Part 1 The Side Effects of Stimulants

Stimulants are also categorized into two types: those based on methylphenidate and amphetamine. Both types work rapidly and wear off in a few hours (3-5 hours for short-acting formulations or 8-12 hours for long-acting ones). They also have similar side effects, the most common of which are:

  • Appetite suppression is among the most prevalent side effects. Appetite may or may not return after a few weeks. This side effect should be reported if it doesn’t go away or causes significant weight loss.

  • Insomnia is also relatively widespread with stimulants. Individuals may also grind their teeth at night. This side effect is usually dose-dependent, meaning that reducing the dose may help the person fall asleep.

  • Headaches and stomachaches. Some people find that taking the pill after a meal helps diminish these side effects.

  • Tics (rapid muscle contractions) can affect any muscle but typically involve the face, neck, or shoulders. Caffeine can make tics more severe. Tics tend to go away in a few weeks.

  • Irritability or rapidly changing moods often indicate that the dose is too high.

  • Fast or irregular heartbeat.

  • Dry mouth.

Click the links for a complete list of side effects of Amphetamine and Methylphenidate.

Side effects shouldn’t persist for more than a few days. “Side effects that the patient finds intolerable, or those that last longer than three to five days, warrant a call to your clinician,” recommends Dr. William Dodson, a board-certified adult psychiatrist, in a piece in Additude Magazine.

If a stimulant causes any side effects, sometimes it’s simply a matter of adjusting the dose. Stimulants have an individual therapeutic window, meaning that a dose that is either too high or too low will not work. Similarly, decreasing or increasing the dose can also reduce side effects.

Switching to a different formulation or type of stimulant can help those with persistent side effects. Alternatively, a non-stimulant may also be prescribed. Read all about the side effects of non-stimulants in Part 2 of this blog post.

The Common Side Effects of ADHD Medications

Part 2 The side effects of non-stimulant ADHD medication

Since the early 2000s, several novel medications have been approved for managing ADHD. Some of them are developed explicitly as ADHD medications, whereas others are primarily used as antidepressants or blood pressure drugs but were also found to reduce symptoms of ADHD. These medications are collectively known as non-stimulants.

According to the National Institute of Mental Health, non-stimulants are prescribed “when a person has bothersome side effects from stimulants, when a stimulant was not effective, or in combination with a stimulant to increase effectiveness.”

Non-stimulant medications are gaining popularity as complementary or primary therapy for ADHD, especially among adults. Adults with ADHD are more likely than kids and teenagers to take non-stimulants to manage their ADHD. “Only one-third of all stimulant use for ADHD is in adults. On the other hand, two-thirds of all atomoxetine [a common non-stimulant] use is in adults,” points out Prof. Stephen M. Stahl, author and professor of psychiatry at the University of California, San Diego, in his book Stahl’s Essential Psychopharmacology.

Non-stimulants take a few weeks to months in order to arrive at their full effect. Once the threshold is reached, they work for the entire day. The convenience of taking only one pill a day, along with a low risk of abuse and the absence of cardiovascular side effects, make non-stimulant medications an appealing choice for managing adult ADHD, in particular.

So what non-stimulants are used for ADHD? Some of the brand names are Strattera, Wellbutrin, and Intuniv, but it’s more convenient to discuss them according to type:

1. Norepinephrine reuptake inhibitors:

  • Atomoxetine (Strattera)

  • Viloxazine (Qelbree).

2. Tricyclic and Atypical Antidepressants:

  • Bupropion (Wellbutrin)

  • Imipramine (Tofranil)

  • Nortriptyline (Pamelor)

  • Desipramine (Norpramine).

3. Alpha agonists:

  • Clonidine (Kapvay)

  • Guanfacine (Intuniv) – currently only approved for ages 6-17.

All of these medications can cause fatigue and daytime sleepiness that typically fade away after a few weeks of taking non-stimulants. If that doesn’t help, decreasing or spacing out the dose of the medication into three smaller doses throughout the day can sometimes reduce daytime sedation.

Atomoxetine and tricyclic antidepressants may also trigger digestive side effects, such as stomachaches, constipation, reduced appetite, and nausea. As with fatigue, these side effects are often temporary and tend to diminish when one splits their daily dosage into 2-3 parts.

Another common side effect of atomoxetine and tricyclic antidepressants is dizziness. Be careful while exercising or doing any rapid movement for the first few days when trying one of these medications. Fortunately, this effect usually dissipates within a week or so.

Non-stimulants can also affect blood pressure or cause an irregular heartbeat or rapid pulse. Report this side effect immediately, especially if you’re already taking blood pressure medications or have any underlying heart condition

Other potential side effects include:

  • Rash or itchy skin

  • Mood swings

  • Dry mouth

  • Blurred vision.

For an exhaustive list of side effects for various non-stimulants, follow these links:

  1. Atomoxetine (Strattera)

  2. Viloxazine (Qelbree)

  3. Bupropion (Wellbutrin)

  4. Imipramine (Tofranil)

  5. Nortriptyline (Pamelor)

  6. Desipramine (Norpramine)

  7. Clonidine (Catepres)

  8. Guanfacine (Intuniv).

Some side effects, such as dry mouth or itchy skin, can be easily managed topically. For example, using lozenges can help rehydrate the mouth and throat. Still, more severe side effects shouldn’t be tolerated, especially when other medication options are available.

If the side effects become too bothersome, avoid abruptly discontinuing non-stimulant medications. Such non-stimulants as tricyclic antidepressants require a gradual tapering off under supervision. A rapid stop can lead to severe symptoms, such as muscle pain, headaches, mood swings, and insomnia.

Lastly, don't worry if a medication doesn’t meet expectations or causes unpleasant side effects. Try and understand what aspects of the medication are bothersome, and use this information to arrive at the best option together with a prescribing doctor. Just like everyone has a unique way of approaching a daily routine, there’s no one-size fits all medication regimen, and that’s fine because there are plenty of combinations to choose from.

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