Strattera (atomoxetine) causes stomach-related side effects in most people who take it, and carries a smaller risk of cardiovascular, liver, and psychiatric effects that deserve attention. Unlike stimulant ADHD medications, Strattera works by boosting norepinephrine activity in the brain, which gives it a different side effect profile. Here’s what to expect and what to watch for.
The Most Common Side Effects
The side effects people notice first are usually digestive. Decreased appetite, nausea, and stomach pain are among the most frequently reported issues in both children and adults. Constipation, dry mouth, and heartburn also show up regularly. These tend to be most noticeable during the first few weeks of treatment and often ease as your body adjusts.
Beyond the gut, common effects include headache, dizziness, fatigue, and trouble sleeping. Some people experience the opposite of insomnia and feel unusually drowsy, especially early on. Irritability and mood changes can occur in both children and adults, though they’re reported more often in younger patients.
How quickly you ramp up the dose matters. Research comparing a fast titration schedule (reaching the full dose in about three days) to a slower one (building up over one to two weeks with twice-daily dosing) found that the faster approach produced significantly more appetite loss, drowsiness, and fatigue during the first week. Starting low and increasing gradually is one of the most effective ways to reduce early side effects.
Effects on Heart Rate and Blood Pressure
Strattera raises heart rate and blood pressure in a meaningful number of people. Roughly 6 to 12% of both children and adults experience clinically important jumps, defined as a blood pressure increase of 15 to 20 mmHg or a heart rate increase of 20 or more beats per minute. Of those affected, between 15 and 32% see sustained or progressive increases rather than a temporary spike.
This doesn’t cause problems for most healthy people, but it’s a real concern if you already have high blood pressure, a fast resting heart rate, or any form of cardiovascular disease. Blood pressure and pulse should be checked before starting the medication, after each dose adjustment, and at least every six months during treatment. If you notice a pounding or racing heartbeat, chest pain, or shortness of breath while taking Strattera, those symptoms need prompt evaluation.
Sexual Side Effects in Adults
Adults taking Strattera commonly report sexual side effects that don’t appear in the pediatric data. These include decreased sex drive, difficulty getting or maintaining an erection, and problems with ejaculation or orgasm. Changes in menstrual bleeding patterns, including heavier periods or spotting between cycles, have also been reported. These effects can be persistent for some people and are worth discussing with a prescriber if they’re affecting quality of life.
Suicidal Thinking in Children and Teens
Strattera carries an FDA black box warning, the most serious type, regarding suicidal ideation in children and adolescents. In pooled data from 12 short-term trials involving over 2,200 young patients, 0.4% of those taking Strattera developed suicidal thoughts compared to zero in the placebo group. No actual suicides occurred in any of these trials.
The risk is highest during the first few months of treatment and around dose changes. Symptoms to watch for include new or worsening anxiety, agitation, panic attacks, insomnia, hostility, aggression, impulsivity, and restlessness. These may appear before or alongside suicidal thoughts. Families and caregivers of young people starting Strattera should stay alert for behavioral changes, particularly anything that feels sudden or out of character.
Liver Injury
Severe liver damage is rare but has been reported after Strattera reached the market. It didn’t appear in clinical trials involving roughly 6,000 patients, so the actual incidence is very low. Most reported cases developed within the first 120 days of treatment, and some involved dramatically elevated liver enzymes (more than 20 times the normal level) along with jaundice.
The good news is that liver injury reversed after the medication was stopped. Warning signs include yellowing of the skin or eyes, dark urine, pain in the upper right side of the abdomen, itching, or unexplained flu-like symptoms. If any of these appear, the medication should be discontinued and not restarted.
Effects on Weight and Growth in Children
Parents often worry about whether Strattera will stunt their child’s growth. A study tracking 419 children over at least two years of continuous treatment found the effects were minimal. On average, children dropped about 2.7 percentiles in weight, which translates to roughly 2 pounds less than predicted. Height was similarly stable, with an average decrease of just 2.2 percentiles on the growth curve, or about half a centimeter below expected height after two years.
That said, appetite suppression is one of the most common side effects, and some children do lose weight early in treatment. Monitoring growth over time is standard practice, and most kids stay on a normal trajectory.
Other Psychiatric Effects
Beyond the suicidality warning, Strattera has been linked to a range of mood and behavior changes. Reported symptoms include irritability, aggression, mood swings, agitation, and in some cases hypomania or mania (periods of abnormally elevated energy and mood). These can occur in both adults and children, though they’re more closely tracked in younger patients because of the overlap with the suicidality concern.
Not every mood shift signals a serious problem. Mild irritability during the adjustment period is common and often fades. But sudden personality changes, intense agitation, or impulsive behavior that feels out of proportion to the situation warrants a conversation with the prescribing provider, especially if these symptoms weren’t present before starting the medication.
What Helps Reduce Side Effects
The single most effective strategy is a slow dose increase. Starting at a lower dose and building up over one to two weeks, ideally split into two daily doses rather than one, significantly lowers the chance of early side effects like nausea, appetite loss, and fatigue. Many of the common side effects peak during the first one to two weeks and then gradually improve as the body adjusts.
Taking Strattera with food can help with nausea and stomach discomfort. For sleep-related issues, the timing of the dose matters. If Strattera makes you drowsy, taking it in the evening may work better. If it disrupts sleep, a morning dose is preferable. These are simple adjustments, but they make a noticeable difference for many people.