Many Australians with ADHD who take Vyvanse (lisdexamfetamine dimesilate) are facing a medication crisis. The drug has been in short supply in Australia for the past few months.

One of the most important aspects of treating a patient with stimulant medication for ADHD is finding the right dose of the medication that suits them best. This involves dose titration, starting low and gradually increasing the dose, looking for the most effective dose, with minimal or manageable side effects. If one stimulant is not effective or not well tolerated, an alternative stimulant may be tried. Therefore, your patient may have reached their present dose of ADHD medication after an extensive process of dose optimisation. This has made current shortages of Vyvanse (lisdexamfetamine dimesilate) particularly difficult for many patients.

Shortages have affected different doses

In August 2023 the first shortages occurred in Australia, affecting the 20mg and 30mg strengths. Then these lower strengths came back, and other dosages became unavailable. By December 2023, most pharmacies only had the 20mg and 70mg capsules available, although now even these are in short supply. Shortages of the 30mg, 40mg and 60mg have persisted, while the 50 mg dose returned earlier this month.

Splitting the dose (for example prescribing 40mg to a patient who takes 20mg) can be done by mixing the contents of a capsule in water, and drinking half one day and half the next. But this is not recommended by the manufacturer, who will not guarantee the effectiveness of the half dose kept overnight.

Combining doses if available (say 20mg and 30mg for a patient who normally takes 50mg) would require two new prescriptions. These strengths might not be available at the pharmacy the following month. As a specialist with perhaps 100 patients on Vyvanse, writing new prescriptions for each patient month by month is not sustainable.

Stimulant prescribing is heavily regulated, with pharmacies allowed to dispense only one month’s supply at a time.

Prescriptions, which usually last for six months, remain at the pharmacy and cannot be released to be used elsewhere, even when a strength might only be available at a different pharmacy.

Of course, Vyvanse is not the only ADHD medication. Some people may have been taking Concerta or Ritalin prior to starting Vyvanse, and could revert to their previous dose without having to go through the initial process of dose titration. Changing medication is not normally a problem, but it might be for someone who has previously tried other formulations and responds better to Vyvanse.

Another alternative would be going back to multiple doses of short-acting dexamfetamine. Vyvanse is a prodrug of dexamfetamine – it has a lysine molecule attached which makes inactive until it has been broken down in the body and releases dexamfetamine. This changes the pharmacokinetics such that a single dose of Vyvanse lasts for 8-12 hours. But it means that the correct dose of dexamfetamine tablets cannot be calculated from a patient’s Vyvanse dose.

So changing to dexamfetamine would have to involve some flexibility for the patient to adjust the dose up or down as needed. This process depends on the person developing a good understanding of their response to each dose of medication. In some cases, this could be positive because in the long term, having a good understanding of the effects of their medication is important for optimising their day-to-day functioning.

There’s no ideal solution to this problem. Leaving patients unmedicated is perhaps the worst option because the functional improvement they have come to depend on is withdrawn and the problems associated with untreated ADHD recur. This can leave people in crisis and seeking unproven alternative treatments.

How long will the shortage last?

In Australia, Vyvanse is only available from one company, Takeda, that manufactures it in the United States.

The Therapeutic Goods Administration anticipates the shortages of Vyvanse 40 mg to last until 30 April 2023, and 19 April 2024 for Vyvanse 60 mg. Normal supplies of Vyvanse 30 mg are expected to resume from 31 March, 2024. The shortage of the 50mg dose has now been resolved.

Key points for GPs

The crisis in Vyvanse supply is compounded by the fact that many specialists are already overstretched and may not be confident that their patients can manage dose titration of short acting stimulants without close supervision.

On the other hand, GPs, who would each have fewer patients with ADHD, may be able to support their patients through this process.

In most states in Australia GPs can also co-prescribe stimulants with the endorsement of a specialist, although this endorsement is not required in Queensland. Therefore, GPs may be able to assist with stop-gap measures to keep their patients on medication through this crisis.

If you have a patient who cannot access their usual medication, remember Vyvanse is not the only formulation available. It’s worth getting in touch with the patient’s specialist to explore the alternatives. This could involve an initial period of dose adjustment of short-acting stimulants, but it might be a great deal better than your patient going without.

Disclosure statement

Alison Poulton is a director of the Australasian ADHD Professionals Association. She has previously taken part in an advisory panel and received personal fees and non-financial support from Takeda Pharmaceuticals, which manufactures ADHD medications including some mentioned in this article. She has received book royalties from Disruptive Publishing (ADHD Made Simple).

This article was adapted with permission from the author. It was first published in The Conversation under a Creative Commons license. Read the original article.