Amphetamine/dextroamphetamine is a prescription stimulant medication used primarily to treat attention deficit hyperactivity disorder (ADHD) and narcolepsy. You probably know it by its most common brand name, Adderall. The medication is a combination of four amphetamine salts that work together to improve focus, attention, and impulse control. It’s classified as a Schedule II controlled substance, meaning it has recognized medical value but also carries a high potential for abuse and dependence.
How It Works in the Brain
The core job of this medication is to increase the activity of two chemical messengers in the brain: dopamine and norepinephrine. These chemicals play a major role in executive function, the set of mental skills that lets you plan, pay attention, remember instructions, and manage impulses. In people with ADHD, the circuits that rely on dopamine and norepinephrine tend to be underactive, which is why concentration and self-regulation feel so difficult.
Amphetamine/dextroamphetamine raises levels of these chemicals in several ways at once. It blocks the transporters that normally vacuum dopamine and norepinephrine back into nerve cells after they’ve been released, keeping them active longer. It also pushes additional dopamine and norepinephrine out of storage inside nerve cells, and it slows the enzyme that breaks these chemicals down. The net effect is more signaling in the parts of the brain responsible for attention and behavioral control.
Immediate-Release vs. Extended-Release
The medication comes in two main formulations, and the practical difference between them is how long they last.
The immediate-release tablet reaches peak levels in the bloodstream about 3 hours after you take it. Its effects generally wear off within 4 to 6 hours, so many people take it two or three times a day to maintain coverage throughout the day.
The extended-release capsule (Adderall XR) uses a two-pulse bead system. Half the beads dissolve right away, and the other half dissolve hours later, mimicking a second dose. Peak blood levels don’t arrive until about 7 hours after the capsule is swallowed, roughly 4 hours later than the immediate-release version. This design provides coverage for most of the waking day with a single morning dose, which is especially practical for children and anyone who would otherwise need to take a midday pill at school or work.
Typical Dosing
Starting doses vary by age. Children ages 6 to 12 typically begin at 10 mg once daily in the morning for the extended-release form, though some start at 5 mg. The dose can be adjusted in 5 or 10 mg steps each week, up to a maximum of 30 mg per day. Adolescents ages 13 to 17 also start at 10 mg daily, with the option to increase to 20 mg after one week if symptoms aren’t well controlled. Adults starting treatment for the first time are usually prescribed 20 mg per day.
These are guidelines, not rigid rules. Doctors adjust doses based on how well symptoms improve and how tolerable the side effects are. Some people do well on a low dose, while others need more.
Common Side Effects
The most frequently reported side effects reflect the drug’s stimulant nature. Appetite suppression is one of the most noticeable, and it’s the reason many people on this medication lose weight, especially in the first few months. Trouble falling asleep is also common, particularly if the medication is taken too late in the day. Other typical effects include dry mouth, headache, increased heart rate, stomach discomfort, and feelings of restlessness or irritability.
Most of these side effects are dose-dependent, meaning they tend to improve when the dose is lowered. Some also fade as your body adjusts over the first few weeks of treatment.
Serious Risks and Warnings
Because amphetamine/dextroamphetamine raises heart rate and blood pressure, it’s not appropriate for people with certain cardiovascular conditions. Those with irregular heartbeats, structural heart defects, uncontrolled high blood pressure, hardening of the arteries, or other heart or blood vessel disease are generally told not to take it.
The medication is also not prescribed to people with glaucoma, overactive thyroid, or significant anxiety, tension, or agitation, since stimulants can worsen all of these. A personal or family history of substance misuse is another major consideration. Doctors are unlikely to prescribe it if there’s a pattern of alcohol overuse, street drug use, or misuse of prescription medications.
Older adults are generally steered toward other treatments, as this medication carries more risk in that population relative to safer alternatives.
Drug Interactions to Know About
The most dangerous interaction is with a class of medications called MAO inhibitors, which are sometimes used for depression or Parkinson’s disease. Taking amphetamine/dextroamphetamine alongside an MAO inhibitor, or within two weeks of stopping one, can trigger a dangerous spike in blood pressure and other serious reactions. If you’ve taken an MAO inhibitor recently, you need to wait at least 14 days before starting this medication.
Controlled Substance Restrictions
As a Schedule II drug, amphetamine/dextroamphetamine comes with stricter prescription rules than most medications. You cannot get automatic refills. Each fill requires a new prescription from your doctor, and in many states prescriptions can only be written for a 30-day supply at a time. Some pharmacies and insurance plans impose additional verification steps. This means staying on top of appointments and prescription timelines is part of taking this medication.
Ongoing Supply Shortages
If you’ve had trouble filling a prescription recently, you’re not alone. The immediate-release version of amphetamine mixed salts has been on shortage for an extended period, driven by a combination of active ingredient delays, increased demand, and manufacturer discontinuations. Several generic manufacturers have limited stock or products on back order, and some have exited the market entirely. The brand-name version (Adderall) and certain generics remain available, but supplies fluctuate by strength and region.
The CDC issued a health advisory noting that disrupted access to prescription stimulants may increase risks for injury and overdose, particularly if people turn to unregulated sources. If your pharmacy is out of stock, calling multiple pharmacies in your area, asking your doctor about alternative formulations, and checking with your insurer about covered alternatives are the most practical steps.