Atomoxetine (Oral)

One of the drugs most often used in the treatment of ADHD is atomoxetine, which works by achieving a balance among the neurotransmitters in the brain.

Overview

Atomoxetine is a drug which is used as one component in a complete program of treatment when managing attention deficit hyperactivity disorder (ADHD). The other components in this total program would address social, psychological, and other factors, whereas atomoxetine specifically focuses on the medical aspect of treatment. What the drug does for a patient is to help increase their ability to stay focused and concentrate, and to reduce nervous activities such as fidgeting and other expressions of unneeded motion. Although more research is needed to understand exactly how these effects are achieved, it is currently believed that it promotes better concentration in patients by restoring the balance of neurotransmitters found in the brain.

Condition Treated

  • Attention Deficit Hyperactivity Disorder (ADHD)
  • Obstructive Sleep Apnea

Type of Medicine

  • ADHD Agent

Side Effects

Whenever a doctor prescribes atomoxetine for a patient in treating ADHD, it is because in the doctor's judgment, the benefits of using the drug will significantly outweigh any side effects which might be attendant upon usage. In most cases, patients using atomoxetine will not experience any serious side effects at all, although in rare cases some serious side effects have been reported.

For the vast majority of atomoxetine users, side effects do not go beyond uncomfortable or inconvenient manifestations out of their ordinary experience. The most frequent side effects reported include the following:

  • difficulty sleeping
  • decrease in sexual ability or desire
  • menstrual cramping and irregular periods in women
  • occasional bouts of dizziness
  • dry mouth
  • nausea and/or vomiting
  • constipation
  • upset stomach
  • excessive fatigue
  • loss of appetite sometimes leading to weight loss
  • elevated blood pressure
  • difficulty urinating
  • irregular heartbeat
  • numbness or tingling in the extremities
  • fainting
  • liver problems such as dark urine or yellowing eyes or skin
  • painful or extended erections in males.

There are times when more serious side effects have been experienced by users of atomoxetine, one of which is liver disease. The onset of liver disease can be identified by symptoms such as persistent nausea and vomiting accompanied by loss of appetite, persistent stomach and abdominal pain, jaundiced eyes or skin color, and dark-colored urine. If any of these symptoms or several of them appear in tandem, contact your physician immediately, so that attempts may be made to reverse any liver damage.

It is also possible that atomoxetine may lead to serious heart problems such as a stroke or heart attack. If you should experience any of the warning signals of an impending coronary problem, you should immediately contact your family doctor. The signs to look for are: pain in the chest, jaw, or left arm, unusual shortness of breath, persistent sweating, abnormal weakness on one side of the body, sudden changes in your vision, slurred speech, and general confusion or disorientation.

There have also been some rare cases where a serious allergic reaction to atomoxetine has been reported, and the warning signs of this are a persistent rash, itching or swelling noticeable on the tongue, throat or in the facial area, severe dizziness, and difficulty with respiratory functions.

Dosage

Before using atomoxetine, and every time you get a refill, you should thoroughly read the Medication Guide in case anything has changed in the guide, or in case your dosage has been modified. Atomoxetine should be taken as directed by your family physician, either with or without food, once or twice daily per your doctor.

The initial dosage should be taken as soon as you wake up in the morning, and if a second dosage has been prescribed as part of your treatment plan, this is most often meant to be taken late in the afternoon or early in the evening. The drug should not be taken late in the evening when it's close to bedtime, because for some people it causes sleeping problems.

Atomoxetine capsules should be swallowed whole without opening them, without crushing the capsules, and without chewing/eating the powder inside. If any capsule should become cracked or opened up, it is highly advisable to avoid contact with the powder, and if contact is made, your skin should be thoroughly washed with soap and water at the earliest opportunity. If the powder gets anywhere near your eyes, they should be flushed out immediately with water, and you should contact your family physician for any further instructions. Any loose powder falling out of the capsule onto the floor or furniture should be immediately cleaned up, and the area where it fell should be washed.

In order for your doctor to make the most optimum prescription schedule for your atomoxetine dosage, you should advise him/her about all medications you are currently taking, as well as any vitamins or herbal supplements which are part of your daily routine. You should never increase the dosage in any way, or alter the prescribed dosage given by your doctor. Atomoxetine is most effective when taken at the same time every day, and regular usage is the best way to achieve maximum benefits from taking the drug.

For adults, 40 mg of atomoxetine may be administered for an initial dosage, and this can be increased after three days or more, up to as much as 80 mg in a given day, with dosage to be divided evenly in 12-hour ingestions. If the desired response is not achieved with the 80 mg dosage, doctors may recommend a somewhat higher dosage, up to 100 mg daily.

For pediatric patients aged six years and above, 0.5 mg per kg of weight should be the initial treatment, and after three days this can be increased to 1.2 mg per kg of weight, divided out over two equal daily dosages. For children weighing greater than 70 kg, 40 mg is the indicated dosage initially, and this can be increased after three days to as much as 80 mg, divided out over 12-hour periods.

Interactions

Patients using atomoxetine should always keep a list of all other prescription drugs being taken, as well as any over-the-counter drugs, vitamins, and herbal supplements, as well as the dosage for each one of these. This list will be very important during an initial consultation with your doctor, when he/she is deciding upon dosages of atomoxetine which you should be prescribed. It will also be important so that a doctor can review the list to determine if there might be any possible interactions with other drugs you are currently taking.

If you should ever have a need for visiting an emergency room or healthcare clinic for unscheduled treatment, this prepared list of medications will be invaluable. Most medical personnel at such clinics are reluctant to prescribe any medications without knowing exactly which drugs you are currently taking, because they don't want to risk drug interactions. This is another great reason to keep your list of medications available and updated whenever anything changes with regard to additions, subtractions, or dosage modifications.

Atomoxetine is known to have moderate interactions with more than 50 other different drugs, and these will be known to your family doctor. In addition, there are a few drugs with which atomoxetine has a severe interaction, including all of the following:

  • tranylcypromine
  • selegiline
  • selegiline transdermal
  • rasagiline
  • procarbazine
  • phenelzine
  • linezolid
  • iobenguane 123
  • isocarboxazid

Warnings

There are a number of warnings associated with atomoxetine usage, and these precautions should be observed by all patients, so as to avoid major issues. Some of these precautions refer to all users, and some are more specific to age groups. For instance, atomoxetine has been known to lead to an increased risk of suicidal thinking, and in some cases actions, in children or adolescents, so patients with any history of such behavior would have to be carefully monitored during treatment.

It's also possible that suicidal thoughts or actions could develop during the program of treatment, so it becomes important for family members and people in the immediate support network of children and teens to be watchful for such behaviors, and to report them immediately to the family physician.

Anyone known to be allergic to atomoxetine should not begin a treatment program which includes the drug, and if any of the symptoms of an allergic reaction should develop, atomoxetine treatment should be discontinued immediately. Such symptoms would include the development of a rash, hives, difficulty breathing, and inflammation or swelling in certain areas of the body.

As with most prescription drugs, atomoxetine should always be kept out of the reach of children or where pets can access it, and if you suspect that either pets or children have ingested atomoxetine accidentally, you should immediately contact the Poison Control Center for instructions on how to proceed.

Atomoxetine should not be used for patients who have a history of hypersensitivity, or who have a known condition of narrow angle glaucoma. It should also not be used by patients with severe cardiovascular disorders, where the potential exists for the deterioration of that disorder if blood pressure were to increase, or if the heart rate were to increase by as much as 20 bpm.

Patients who currently have pheochromocytoma, or who have had a previous history of the condition, should not be prescribed atomoxetine, because it can cause serious reactions such as tacharrhythmia or dangerously elevated blood pressure.

Atomoxetine should not be used within two weeks of therapy involving monoamine oxidase inhibitors (MAOIs). In these situations, there is at least a slight risk of incurring reactions which could prove to be fatal, including severely altered mental status, myoclonus, hyperthermia, and neuroleptic malignant syndrome.

There are a number of other precautions which atomoxetine patients should be aware of, including all of the following:

  • children and adolescents with ADHD often demonstrate hostility or unusually aggressive behavior, and this should be monitored for its initial appearance, or for an identifiable worsening
  • risk of allergic reaction
  • patients who have structural cardiac abnormalities may have increased risk of heart attack, stroke, and possibly even sudden death when taking atomoxetine, even at a normal dose
  • all patients considering a treatment program of atomoxetine should have a very detailed heart exam and workup of heart history, so that any presence of cardiovascular abnormality or disease can be considered before atomoxetine treatment
  • there is a risk of liver injury within the first 120 days of taking atomoxetine, so patients with elevated readings of liver enzymes, jaundiced skin or eyes, or much higher bilirubin levels than normal, should immediately discontinue usage of atomoxetine and report symptoms to the doctor
  • if atomoxetine is administered in conjunction with a CYP2D6 inhibitor, any dosage adjustment should be implemented four or more weeks after initiation
  • some patients experience low blood pressure when taking atomoxetine, which can result in dizziness when standing up suddenly, and this can even cause fainting spells
  • children and adolescents are sometimes subject to increased risk of suicidal thoughts and actions
  • some patients have developed symptoms such as unexplained syncope, or exertional chest pain when taking atomoxetine, and this should be followed up promptly with a full cardiac evaluation
  • any patient who has a history of bipolar disorder may be at risk when taking atomoxetine for potential induction of a mixed manic episode
  • some allergic reactions have been reported by atomoxetine users, including hives, rashes, edemas, and anaphylactic reactions
  • some instances of priapism have been reported among atomoxetine users, and some of these cases have required surgery. Although not generally reported during the initial phase, priapism has sometimes been manifested when dosage increases have been implemented. If such manifestations should occur, immediately seek medical advice or attention in order to resolve the issue
  • in some children and adolescents, sensory disturbances are possible, as well as paresthesia or hyperesthesia
  • child users of atomoxetine between the ages of 7 to 10 years should be carefully monitored with regard to their growth and weight gain. Anything unusual reported in these areas may call for discontinuance of atomoxetine treatment
  • difficulty urinating is possible with atomoxetine usage
  • some patients have reported decreased sexual desire or decreased sexual performance when using atomoxetine
  • atomoxetine should be used cautiously in patients who have any history of high blood pressure, tachycardia, or irregular heartbeat
  • atomoxetine should be used carefully by women who are pregnant or who plan to become pregnant, although there is inadequate research to suggest that there is any real harm possible from taking atomoxetine during pregnancy
  • it is not known whether or not atomoxetine is present in breast milk, so that it can be passed on to an infant. Any woman who plans to breastfeed while taking atomoxetine should consult the family doctor for advice on how to proceed.

Storage

Atomoxetine should be stored in a location where pets and curious children cannot access it, usually somewhere high up and well out of reach, even by climbing. The conditions in the area of storage should not have direct, bright lighting, nor should it be warmer than room temperature or cold enough to freeze. Excessive humidity may also degrade the drug or decrease its effectiveness, so it is not advisable to store it in a bathroom, where showering and bathing can often generate considerable moisture in the air.

If you suspect that children or animals in the household have accessed your atomoxetine prescription, you should call the local Poison Control Center for instructions on how to proceed. This will usually include some kind of flushing treatment to remove the drug from the body, or in some cases, it might be suggested that the person/animal affected be taken to an emergency care outlet.

It's also not a good idea to store your atomoxetine prescription in a 7-day pill reminder container, because very few of these are equipped with any kind of access controls, so it's fairly easy for a child to open up the case and take the drugs inside. For this same reason, wherever you do store your atomoxetine prescription, the cap should always be twisted on tightly, and secure from accidental child opening.

Summary

Atomoxetine has been shown to be medically very effective in the treatment of ADHD, when used in combination with other treatments that address social and psychological aspects of the disorder. Because ADHD is a disorder which often affects young persons, though there is a very particular need to closely monitor all patients using this drug for the development of, or the worsening of, any of the indications mentioned above, in the order of side effects and changes in behavior.

In some cases, it will be necessary to discontinue usage of atomoxetine if some of the side effects exhibited by a patient are serious enough to warrant a stoppage of treatment. In such situations, there may be other drugs that your family doctor would like to substitute as an alternative treatment. In all cases however, whenever side effects are noticeable enough that family members and support network personnel have identified them, the family doctor will have to weigh the benefits of usage against the presence of the side effects.

Any downside associated with atomoxetine usage has historically been limited to relatively minor manifestations, although more serious developments have been noted in rare cases. Allergic reactions to atomoxetine are uncommon, but have been recorded by some users, and some other unusual side effects have also been experienced as a result of usage.

Most interactions between atomoxetine and other drugs are relatively mild, although there are a handful of other prescription drugs which are known to have fairly severe reactions with atomoxetine. Your family doctor will be aware of interactions with other drugs, both mild and severe, so that's why it is extremely important that you have a full list of your other medications, vitamins, herbal supplements, and any over-the-counter drugs you are taking. This list will be critical in the determination of any possible interactions with atomoxetine, as well as in deciding whether or not dosages of your other medications will need to be altered while taking atomoxetine.

Fortunately, it is not usually necessary to take routine laboratory tests while on a treatment program of atomoxetine, although your family physician may want to take periodic checks of your blood pressure, heart rate, and other vital signs to be sure that no undesirable side effects are developing.

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Last Reviewed:
December 23, 2017
Last Updated:
April 04, 2018
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