Amphetamine: what it treats, how to take it, side effects
Last updated September 7, 2026.
**Amphetamine is a prescription central nervous system stimulant in the amphetamine class, used mainly for attention deficit hyperactivity disorder (ADHD) and narcolepsy.** It increases the activity of norepinephrine and dopamine in the brain, which improves attention, reduces impulsive and hyperactive behavior, and helps you stay awake. The most important safety point is that amphetamine is a Schedule II controlled substance with a high potential for misuse and dependence, so take only your prescribed amount, keep it locked away, and never share it.
What does it treat?
Amphetamine is approved to treat ADHD in children age 3 and older and in adults, where the target pattern is long-standing trouble sustaining attention, distractibility, disorganization, restlessness, or impulsive decisions that show up in more than one setting such as school, work, and home. It is also approved for narcolepsy, a sleep disorder with excessive daytime sleepiness and sudden sleep attacks. Amphetamine sulfate tablets (Evekeo) carry an additional short-term approval for exogenous obesity as part of a weight-reduction program. You will see the drug sold as single-ingredient amphetamine products, including immediate-release tablets, extended-release orally disintegrating tablets (Adzenys XR-ODT), and extended-release oral suspension (Dyanavel XR), and as combination mixed amphetamine salts with dextroamphetamine (Adderall, Adderall XR, Mydayis).
How do you take it?
Amphetamine comes as immediate-release tablets, extended-release capsules and tablets, orally disintegrating tablets, and a liquid suspension. For ADHD with immediate-release amphetamine sulfate, adults and children 6 and older usually start at 5 mg once or twice daily and increase by 5 mg per week; children 3 to 5 start at 2.5 mg daily and increase by 2.5 mg per week. The label says a total daily dose above 40 mg is rarely needed for ADHD. For narcolepsy the usual range is 5 to 60 mg per day in divided doses. Extended-release forms are taken once each morning and have their own ceilings, such as 20 mg per day for Dyanavel XR oral suspension. Immediate-release doses are spaced 4 to 6 hours apart, with the first dose on waking and the last dose several hours before bedtime so it does not block sleep. You can take amphetamine with or without food, though taking it with food can ease stomach upset; shake the suspension before each dose and measure it with the supplied device, not a kitchen spoon. Acidic drinks such as large amounts of fruit juice and vitamin C supplements can lower how much drug you absorb. If you miss a dose, take it when you remember unless it is late in the day, then skip it and go back to your schedule; never double up. Do not stop a high or long-standing dose abruptly on your own, since that can cause severe fatigue, depression, and sleep changes. Call your doctor before your next dose if you get chest pain, fainting, new or worsening agitation, hallucinations, or numb, cold, painful fingers or toes.
Side effects to know
- Common: Common effects include decreased appetite, trouble falling asleep, dry mouth, weight loss, headache, stomach pain, nausea, irritability, faster heartbeat, and a rise in blood pressure, and many of these ease over the first few weeks or with a dose or timing change.
- Serious: Stop the drug and get medical help right away for chest pain, shortness of breath, fainting, one-sided weakness or trouble speaking, seizures, new hallucinations, paranoia, mania, or an erection lasting more than 4 hours. Also call promptly for fingers or toes that turn pale, blue, numb, or develop unexplained sores, and for agitation with fever, sweating, muscle twitching, and fast heartbeat, which can signal serotonin syndrome when amphetamine is combined with antidepressants.
Who should not take it?
Do not take amphetamine if you are taking a monoamine oxidase inhibitor (MAOI) such as phenelzine, tranylcypromine, selegiline, isocarboxazid, or linezolid, or have taken one in the past 14 days, or if you have had a serious allergic reaction to amphetamine or another stimulant. Talk to your doctor first if you have a heart defect, cardiomyopathy, a serious heart rhythm problem, coronary artery disease, high blood pressure, a family history of sudden cardiac death, glaucoma, an overactive thyroid, seizures, circulation problems such as Raynaud phenomenon, or a history of bipolar disorder, psychosis, depression, or substance use disorder. Tell your doctor about every medicine you take, especially SSRIs, SNRIs, tricyclics, tramadol, triptans, lithium, blood pressure medicines, and acid-changing products such as antacids, proton pump inhibitors, or urinary acidifiers, since these change amphetamine levels or raise the risk of serotonin syndrome. In pregnancy, FDA labeling advises using amphetamine only if the benefit justifies the risk; babies born to people who used amphetamines during pregnancy have shown higher rates of premature delivery, low birth weight, and withdrawal symptoms, so tell your doctor if you are pregnant or planning to be. Breastfeeding is not recommended during treatment because amphetamine passes into breast milk. Avoid alcohol while taking amphetamine, because the stimulant can mask how intoxicated you feel and both raise strain on your heart.
When is it an emergency?
Call 911 in the US for collapse, chest pain, trouble breathing, a seizure, or one-sided weakness or slurred speech. Call Poison Control at 1-800-222-1222 for any suspected overdose or if a child swallows the medicine, even if the person seems fine. Overdose signs include restlessness, tremor, rapid breathing, confusion, panic, aggression, hallucinations, very fast or irregular heartbeat, high fever, muscle pain or dark urine, seizures, and coma, and these are followed by fatigue and depression. Signs of a severe allergic reaction, including swelling of the face, lips, or tongue, hives, or trouble breathing, are also a 911 call. Bring the bottle or a photo of the label with you.
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Common questions
What is the maximum daily dose of amphetamine?
It depends on the product and what you are treating. For ADHD with immediate-release amphetamine sulfate tablets, the label says doses above 40 mg per day are rarely needed. For narcolepsy the usual range is 5 to 60 mg per day in divided doses. Extended-release products have lower ceilings, for example 20 mg per day for Dyanavel XR oral suspension. Your own limit is whatever your prescriber wrote, and higher doses do not reliably work better, they mostly add sleep loss, appetite loss, and heart rate effects.
Can I drink alcohol while taking amphetamine?
Avoid it. Amphetamine is a stimulant and alcohol is a depressant, so the stimulant can hide how impaired you actually are and lead you to drink more than you intended. The combination also increases the load on your heart and raises the chance of an irregular heartbeat. If you drink at all, keep it to a small amount, never on a day you took an extra dose, and never before driving. Tell your prescriber if you drink regularly, because that changes both the risk and the treatment plan.
Is amphetamine safe during pregnancy or while breastfeeding?
FDA labeling says to use amphetamine during pregnancy only if the potential benefit justifies the potential risk to the fetus. Babies born to people who used amphetamines during pregnancy have shown higher rates of premature delivery, low birth weight, and withdrawal symptoms such as agitation and poor feeding. Do not stop on your own if you find out you are pregnant; call your prescriber, because untreated ADHD or narcolepsy carries its own risks and the decision is individual. Breastfeeding is not recommended while taking amphetamine, since the drug passes into breast milk and can affect the baby.
Should I take amphetamine with food?
You can take it with or without food, and taking it with breakfast often reduces stomach upset. Food does not meaningfully reduce how well it works. What does matter is acid: large amounts of fruit juice, vitamin C supplements, and acidifying products lower how much amphetamine you absorb, while antacids and other alkalinizing products raise it, so keep those consistent and space them from your dose. Shake the oral suspension before measuring, and use the dosing syringe or cup that comes with it. Eat regular meals even without hunger, since appetite suppression and weight loss are common.
What does an amphetamine overdose look like?
Early signs are restlessness, tremor, fast breathing, confusion, panic, aggressive behavior, and hallucinations. As it worsens you can see a very fast or irregular heartbeat, high or low blood pressure, high fever, muscle pain with dark urine from muscle breakdown, seizures, and coma, usually followed by deep fatigue and depression. Call Poison Control at 1-800-222-1222 right away for any suspected overdose, including a child who swallowed a pill, and call 911 for collapse, seizure, chest pain, or trouble breathing. Do not wait to see if symptoms pass and do not try to make the person vomit.
Which medicines interact with amphetamine?
MAOIs such as phenelzine, tranylcypromine, selegiline, isocarboxazid, and the antibiotic linezolid must not be combined with amphetamine, and you need 14 days between them, because the combination can cause a dangerous rise in blood pressure. Serotonergic drugs, including SSRIs, SNRIs, tricyclic antidepressants, tramadol, triptans, and lithium, raise the risk of serotonin syndrome. Blood pressure medicines may work less well while you are on a stimulant. Acid-changing medicines such as antacids and proton pump inhibitors increase amphetamine absorption. Give your prescriber a full list including over-the-counter products, decongestants, and supplements.