Active ingredient: dexamfetamine sulfate · UK brand: Amfexa · US name: Dextroamphetamine (Dexedrine, ProCentra, Zenzedi)
Dexamfetamine is the immediate-release amphetamine prescribed in the UK. Same active molecule as Elvanse, but absorbed directly rather than as a prodrug. Faster onset, shorter duration, more flexible dosing.
Same active molecule. Two ways of getting it into your bloodstream.
Dexamfetamine is the active molecule that Elvanse converts into. The difference between the two medications is not what they ultimately do in your brain — that is identical — but how they get there.
Elvanse is a prodrug. The molecule must be enzymatically converted by your body before it becomes active. The conversion is steady and gradual, which is why Elvanse has a slow onset, a smooth peak and a long tail.
Dexamfetamine is absorbed directly. The active molecule enters your bloodstream as itself, with no conversion needed. Onset is faster, peak is sharper, duration is shorter. Most adults need two or three daily doses to maintain coverage across the day.
UK spelling note. The UK uses dexamfetamine (no 'p'), following Medicines and Healthcare products Regulatory Agency (MHRA) convention. The US spells it dextroamphetamine. The molecule is identical.
Dexamfetamine is one of two amphetamine-based ADHD medications prescribed in the UK.
UK dexamfetamine titration typically starts at 5mg once or twice daily and increases in defined steps. The total daily dose is usually divided across two or three administrations to maintain coverage. Maximum total daily dose for adults is normally 60mg, sometimes higher under specialist supervision.
Available UK doses (Amfexa): 5mg, 10mg, 20mg.
The standard schedule is two or three doses spaced about four to five hours apart. Most prescribers recommend the last dose no later than mid-afternoon to allow the medication to clear before bedtime.
Some adults are prescribed Elvanse in the morning with dexamfetamine as an afternoon top-up. The Elvanse provides the long anchor, the dexamfetamine fills in any late-day gaps. ADHDose handles the combination by modelling each medication's release profile separately.
Dexamfetamine can be taken with or without food. Acidic foods and drinks (large amounts of citrus juice, vitamin C supplements) can slightly reduce absorption. Most prescribers do not consider this clinically significant, but worth being aware of.
ADHDose models each dexamfetamine dose using its direct-absorption profile, calibrated to your dose, your timing and your individual metabolism. Multiple daily doses are stitched into one continuous picture. The Clinician Summary export pulls 28 days of data into NHS prescriber format for your reviews.
Dexamfetamine peaks faster and clears faster than Elvanse. Many adults take it twice or three times a day. ADHDose handles every dose separately and stitches the picture together.
Whether you take dexamfetamine on its own, alongside Elvanse as a top-up, or in a multi-dose schedule, ADHDose handles each dose individually and shows you where you are.
Most people tolerate Dexamfetamine well, especially after the first few weeks. Here are the patterns worth noticing — and the ones that warrant a call to your prescriber.
Most ease in the first two to four weeks. Logging them daily helps you and your prescriber decide whether they are settling or sticking.
Not emergencies, but worth bringing up. ADHDose tags recurring patterns automatically in your daily logs.
Rare, but worth knowing. If you see any of these, contact your prescriber rather than stopping on your own.
The first weeks of Dexamfetamine have a recognisable shape. Knowing what is normal at each stage stops you reading too much into a single bad day.
Most people feel something within the first hour of the first dose. The first few days often involve small wobbles — appetite changes, sleep shifts, occasional headaches. None of this is unusual. Daily logging helps separate first-dose nerves from real side effect patterns.
Side effects from days one to three usually start to ease. The dose-response becomes more predictable. Track focus, sleep and energy daily. This is the data your prescriber wants at your first review.
Most UK and US protocols schedule the first review around week two or four. Your prescriber will ask about effect, side effects, sleep and appetite. Bringing tracked data — rather than relying on memory — turns the review from vague impressions into something concrete.
If the first dose is not quite right, your prescriber will adjust upward in defined steps. Each step is usually held for two to four weeks before the next adjustment. The same daily logging continues.
Once the dose is settled, reviews shift to every six to twelve months. Daily logging becomes lighter — focus and sleep are usually enough. The Clinician Summary export gives prescribers a 28-day window of evidence at each review.
ADHDose makes the milestone view concrete. Daily logs of focus, sleep, energy and side effects across the titration window show the trajectory clearly — to you, and to your prescriber when review day arrives.