Atomoxetine Risks, Warnings, and Complications

SUICIDAL THINKING: Taking atomoxetine can increase the risk of suicidal ideation (thoughts or behaviors of harming yourself). This risk is especially high in children and teenagers and during the first few months of taking the medicine or after a dosage adjustment. Be vigilant for any unusual changes in mood or behavior, including depression, anxiety, panic attacks, trouble sleeping, anger, agitation, or restlessness. Tell your doctor right away if you have suicidal thoughts.

SEVERE LIVER PROBLEMS: Rarely, atomoxetine can cause severe liver injury, which can lead to liver failure. This can happen several months after starting treatment. It is usually temporary, and liver function typically recovers within a few weeks of stopping atomoxetine treatment. Call your doctor right away if you develop right upper abdominal pain, yellowing of the skin or eyes, black or tarry stools, or dark urine. 

SERIOUS CARDIOVASCULAR SIDE EFFECTS: Atomoxetine has been linked to serious cardiovascular events, including stroke, heart attack, and sudden death, especially in people with a history of heart problems. This medication can also cause increased blood pressure and heart rate. Before starting atomoxetine, tell your doctor if you have heart problems. Contact your healthcare provider immediately if you experience chest tightness or pain with exertion, fainting, or an irregular heartbeat while on atomoxetine.

NEW PSYCHOTIC OR MANIC SYMPTOMS: Treatment with atomoxetine can result in new psychotic or manic symptoms such as delusions, hallucinations, or mania in children and adolescents, including those without a history of psychiatric disorders. This can occur even when atomoxetine is taken at the usual doses. Your child’s doctor may discontinue atomoxetine treatment if this happens. 

SCREENING FOR BIPOLAR DISORDER: Atomoxetine can trigger mixed/manic episodes in people with bipolar disorder. Your doctor will screen for this psychiatric condition before starting you on atomoxetine. Tell your provider right away if you or your family members notice any unusual changes in your mood or behavior, such as recklessness, racing thoughts, unusual happiness, excessive talkativeness, or irritability.

AGGRESSIVE BEHAVIOR AND HOSTILITY : Some people develop behavioral changes such as aggression and hostility while on atomoxetine. This medication can worsen existing behavior or mood problems or cause new problems. Tell your healthcare provider without delay if you develop any changes in mood or behavior while on atomoxetine. You may need to stop taking this ADHD medicine.

ALLERGIC REACTIONS: Rarely, atomoxetine can cause severe allergic reactions. Seek emergency medical care if you develop a skin rash, hives, itching, swelling of the face, lips, tongue, or throat, difficulty breathing, or chest pain.

URINARY PROBLEMS: Adults taking atomoxetine can develop urinary retention and urinary hesitation. Tell your provider if you experience any difficulty with urination while on this medicine. 

PRIAPISM: Rarely, atomoxetine can cause priapism (a prolonged and painful erection). If left untreated, this can cause permanent damage to the penis. Seek emergency medical attention if you develop a painful erection that lasts more than 4 hours.

SLOWED GROWTH IN CHILDREN: Studies have shown that atomoxetine inhibits a child’s growth rate. During the first 9 to 12 months of treatment, children taking this medicine have a slower growth rate compared to children who are not on atomoxetine. However, the growth rate usually recovers during continued treatment and does not typically affect the child’s final adult height or weight. Your child's doctor will track your child's growth rate regularly. If they notice slowed growth, they might pause or stop atomoxetine treatment.

POSSIBLE DRUG INTERACTIONS: The clinical pharmacokinetics and clinical efficacy of atomoxetine can be affected by concomitant administration with other drugs. Dosage adjustment of atomoxetine may be needed if it is taken with certain other drugs, such as antidepressants (paroxetine, fluoxetine) and anti-arrhythmic drugs (quinidine), which are inhibitors of an enzyme called CYP2D6. Dose adjustments may also be needed in people who are poor metabolizers of CYP2D6 enzyme (blood tests can be used to identify such individuals).