Dexamphetamine vs Vyvanse vs Ritalin: how your GP chooses

If your GP has confirmed an ADHD diagnosis, the next conversation is about medication. In Australia, three stimulant medications do most of the heavy lifting: dexamphetamine, lisdexamfetamine (Vyvanse), and methylphenidate (Ritalin). They all increase dopamine and noradrenaline in the brain, but they differ in how they get there, how long they last, what they cost, and who they suit best.

This guide explains what your GP weighs up when choosing between these three medications in the Australian system.

In this article

• How each medication works
• Duration of action: short-acting vs long-acting
• PBS listing and cost in Australia
• TGA-approved indications and age ranges
• When GPs choose one over another
• Switching between stimulant medications
• Frequently asked questions

How each medication works

All three stimulants increase the availability of dopamine and noradrenaline in the brain, but their mechanisms differ in ways that matter clinically.

Dexamphetamine is a direct-acting amphetamine. It promotes the release of dopamine and noradrenaline from presynaptic neurons and reverses the reuptake transporters, flooding the synapse with both neurotransmitters. It takes effect within 30 to 60 minutes of oral dosing.

Lisdexamfetamine (Vyvanse) is a prodrug. The molecule is inactive until red blood cells cleave the lysine amino acid from the dexamphetamine component. This enzymatic conversion happens in the bloodstream with a half-life of roughly one hour. The result is a slower, steadier rise in dexamphetamine levels compared to taking dexamphetamine directly. Because the conversion happens in the blood rather than the gut, food has minimal impact on absorption.

Methylphenidate (Ritalin) works differently from both amphetamines. Rather than promoting neurotransmitter release, methylphenidate blocks the dopamine and noradrenaline reuptake transporters. The net effect is similar (more dopamine and noradrenaline available at the synapse) but the mechanism is distinct. This difference matters when a patient responds well to one class but not the other.

Duration of action: short-acting vs long-acting

Duration of action is one of the biggest factors in medication choice. A medication that wears off at 2 pm creates a different daily experience than one that lasts until evening.

Immediate-release formulations

Dexamphetamine IR lasts approximately 4 to 6 hours per dose. Most patients take it two to three times daily. This allows flexible dosing (a smaller afternoon dose if evenings need to be medication-free) but requires remembering multiple doses throughout the day.

Methylphenidate IR (Ritalin) lasts approximately 3 to 4 hours per dose. It typically requires three doses per day, which is manageable but means the medication level fluctuates more throughout the day.

Long-acting formulations

Lisdexamfetamine (Vyvanse) provides the longest duration of any single-dose ADHD medication in Australia: up to 13 hours in children and 14 hours in adults. The prodrug conversion creates a smooth onset over about 90 minutes and a gradual taper. One morning dose covers the entire working day and into the evening.

Methylphenidate modified-release (Ritalin LA, Concerta) uses a capsule or osmotic-release mechanism to deliver methylphenidate over 8 to 12 hours. Concerta uses a push-pull osmotic system that delivers 22% of the dose immediately and 78% over the following hours.

PBS listing and cost in Australia

Cost shapes medication choice in practice. All three stimulants are listed on the Pharmaceutical Benefits Scheme (PBS), but the listing conditions and out-of-pocket costs differ.

Dexamphetamine IR has the broadest PBS listing. It is subsidised for ADHD in both children and adults. The cost per script with PBS subsidy is low, making it the cheapest stimulant option in Australia. For patients on a concession card, the co-payment is around $7.70 per script.

Lisdexamfetamine (Vyvanse) has been PBS-listed for children since 2014 and for adults since February 2021. Before the PBS expansion, an estimated 20,000 Australian adults were paying more than $1,200 per year out of pocket for Vyvanse. Since December 2025, a PBS price adjustment has reduced the listed price. With PBS subsidy, patients pay the standard co-payment (around $31.60 general, $7.70 concession as of 2026).

Methylphenidate (Ritalin, Ritalin LA, Concerta) is PBS-listed for ADHD. The long-acting formulations (Ritalin LA and Concerta) were historically restricted to patients diagnosed before turning 18, but the PBS has progressively expanded adult access. Standard PBS co-payments apply.

If your GP recommends a medication that is not subsidised for your specific situation, you will pay the full private price. Your GP will explain this before writing the script. For more on costs and rebates, see our guide to Medicare rebates for ADHD assessments.

TGA-approved indications and age ranges

The Therapeutic Goods Administration (TGA) approves each medication for specific age ranges. Prescribing outside these ranges is considered off-label, which is legal but requires extra clinical justification.

• Dexamphetamine: TGA-approved for ages 3 to 17. Adult use is off-label but widely accepted in clinical practice and supported by PBS listing.
• Lisdexamfetamine (Vyvanse): TGA-approved for ages 6 to 55 for ADHD. Also TGA-approved for binge eating disorder in adults.
• Methylphenidate (Ritalin IR): TGA-approved for ages 6 to 17. Ritalin LA is approved to age 60, Concerta to age 65.

In practice, Australian GPs prescribe dexamphetamine and methylphenidate IR for adults routinely. The TGA age ranges reflect original registration data, not a clinical prohibition on adult use. Your GP will explain if your prescription involves an off-label indication.

When GPs choose one over another

There is no single “best” ADHD medication. Your GP considers several factors when recommending a starting point.

Vyvanse is often a first choice because

• The 13 to 14 hour duration covers a full working day without needing to remember a second dose. However, some patients report shorter acting duration.
• The prodrug mechanism provides a smoother onset and offset, reducing the “crash” some patients experience with immediate-release formulations
• Lower abuse potential compared to immediate-release stimulants (the prodrug must be enzymatically converted, so snorting or injecting it does not produce a faster high)
• PBS-listed for adults up to age 55, so the cost is subsidised

Dexamphetamine IR suits patients who

• Need flexible dosing (a smaller afternoon dose, or medication-free evenings)
• Are sensitive to long-acting formulations that interfere with sleep
• Want the lowest-cost option available on the PBS
• Prefer to titrate in small increments (dexamphetamine IR tablets come in 5 mg, allowing fine dose adjustments)
• Are over 55 and outside the Vyvanse TGA-approved age range

Methylphenidate (Ritalin) is preferred when

• The patient has not responded well to amphetamine-class medications (dexamphetamine or Vyvanse)
• Side effects from amphetamines are problematic (appetite suppression, anxiety, irritability)
• The patient has a history of tics, which amphetamines are more likely to worsen
• Comorbid anxiety is present and the GP wants to trial a different mechanism of action
• The patient prefers a long-acting formulation with a shorter total duration than Vyvanse (Concerta lasts 10 to 12 hours vs Vyvanse at 13 to 14 hours)

Your GP will typically start with one medication, monitor your response over 4 to 6 weeks, and adjust from there. For a detailed look at what that process involves, see our post on getting the best results from Vyvanse.

Switching between stimulant medications

Switching medications is common and not a sign that treatment has failed. About 30 to 50% of adults with ADHD will try more than one medication before finding the right fit.

If your GP started you on Vyvanse and the side effects are difficult, they might switch you to dexamphetamine IR for more dosing flexibility, or to methylphenidate if the amphetamine class is not suiting you. The reverse also applies: if methylphenidate is not providing enough symptom control, an amphetamine-class medication is the logical next step.

Switches between dexamphetamine IR and Vyvanse are straightforward since both deliver the same active molecule. The dosing conversion is approximately 30 mg of Vyvanse to 10 mg of dexamphetamine, though your GP will adjust based on your response.

During the current methylphenidate shortage in Australia, some patients have been bridged from methylphenidate to dexamphetamine or lisdexamfetamine. Your GP will manage this transition with appropriate dose adjustments.

In Queensland, specialist GPs with RACGP or ACRRM fellowship can now initiate and modify ADHD medications for adults without needing a psychiatrist referral. This means medication adjustments and switches happen faster. Learn more about the Queensland GP prescribing reform.

Frequently asked questions

Choosing between dexamphetamine, Vyvanse, and Ritalin is a clinical decision your GP makes based on your symptoms, daily schedule, side effect profile, and cost considerations. There is no universal “best” stimulant. The right medication is the one that controls your ADHD symptoms across your day with side effects you find manageable.

If you are in Queensland and ready to discuss ADHD medication options with a specialist GP, book a telehealth ADHD assessment or start with our ADHD assessment.