ADHD Medications Available in New Zealand Part 1: Stimulants
Welcome to part one of my two-part series on ADHD medications in New Zealand. Stimulant medications are the most effective evidence-based treatment for ADHD, and work for most people. This makes optimising medication the main factor in managing symptoms in ADHD. But here's the thing - not all medications work the same for everyone. That's why having the right information before talking with your prescriber about what's best for you is incredibly helpful. And that's precisely what this post is all about.
Disclaimer: I am not a medical doctor and cannot prescribe any medications. My knowledge comes from reading textbooks, articles, and listening to podcasts and webinars from ADHD expert psychiatrists and pediatricians. And, of course, from micromanaging my son's stimulant medications since 2020, and discussing medication response and experiences with dozens of ADHD therapy clients.
All stimulant medications for ADHD fall into only two categories: methylphenidate and amphetamine. The best-known methylphenidate medication is branded Ritalin. A commonly known amphetamine medication is branded Adderall and unavailable in New Zealand. Instead, dexamphetamine and lisdexamfetamine are the amphetamine-based medications used here. Methylphenidate and amphetamine preparations greatly increase the availability of dopamine and norepinephrine in the brain's frontal regions (amphetamine stimulates epinephrine more than methylphenidate does), leading to significant enhancements in executive functioning.
Click here to see a psychiatrist explain how methylphenidate and dexamphetamine work in the brain.
Immediate release: Ritalin and Rubifen (tablets) – up to 3-4 hours action with quick onset and offset.
Longer release: Ritalin LA (capsule) and Rubifen SR (tablet) – up to 6-8 hour action. Ritalin LA is effectively two short-acting doses contained in one capsule. An immediate dose, and one that releases around four hours later once an outer coating dissolves in the gut. Rubifen SR is a slower-acting release - although I have not been able to find a published dose-response curve so I can see how it releases over time.
Longest release: Concerta (and Teva is the generic) - 10-12 hours action (although all the clients I know who have tried Teva report a duration of around 6 hours). Concerta works through a sophisticated capsule that involves a fast-release layer, osmosis, and a laser-drilled hole - it's pretty cool. Teva is a pressed powder tablet, and I have not been able to find a published dose-response curve so I can see how it releases over time.
Click here for a video that shows the sophisticated way that Concerta releases methylphenidate in the gut.
Immediate release: 3-4 hours action with quick onset and offset. Generally only used when a trial of methylphenidate formulations has either not alleviated symptoms and/or has produced intolerable side effects.
Sustained release: lisdexamfetamine (branded Vyvanse) has been available in New Zealand since June 2023 and should give 10-12 hours of symptom treatment. As of the time of writing (end of June 2023), it is not Pharmac funded and has been given a low priority for this. Therefore it does cost more, with one quote I have heard of between $80-$120 per month. Vyvanse works by bonding dexamphetamine with another molecule that is removed once in the blood, which then allows the stimulant to take effect. This is chemical management of drug release rather than a mechanical release as performed with the longest-acting methylphenidate formulation Concerta. In the US, Vyvanse is an FDA-approved treatment for binge eating disorder. Vyvanse is a game-changer for those who need an amphetamine preparation, and I look forward to the day when it is funded by Pharmac.
Click here to search the Medsafe data sheets and consumer medical information for each of the above medications.
ADHD medication can be customized to fit the individual's needs. Stimulant medications have a short half-life, meaning they are quickly absorbed and eliminated by the body. To provide longer coverage throughout the day, doctors may prescribe a mix of a longer-acting formulation with an immediate-release tablet as a booster or overlaid.
For adults, it's common to want 12-16 hours of coverage in a day, especially if they have responsibilities in the evening. Even the longest-acting medications, Concerta and Vyvanse, usually only last around 10 hours. This means a booster dose in the later afternoon may be needed to achieve the desired coverage.
GPs often begin treatment for ADHD with the shortest-acting medication, at its lowest dose, with two doses per day. Doses can be increased weekly at this stage. For most people, they are not likely to notice great results with this initial regimen. Managing ADHD symptoms with fast-acting medication can be challenging, as it requires multiple doses throughout the day. For example, when my son was on fast-acting medication, he needed four doses a day, spaced three hours apart, to achieve around 12 hours of symptom relief. This can be difficult for anyone to manage, regardless of whether they have ADHD or not.
In Canterbury, treatment guidelines for GPs recommended a switch to a longer-acting formulation soon after the fast-acting trial, for easier management of symptoms and a smoother dose-response curve. If a booster dose is needed, patients will typically have to request it specifically. Because of the challenges associated with fast-acting medication, dexamphetamine is not typically used as a first-line treatment, due to it until only recently coming in fast-acting form. Vyvanse, if a person can afford the prescription fee, now provides a more manageable option.
When I meet a new ADHD client, I consider these three factors for optimising medication:
Whether they are on the right chemical and formulation,
Whether they are on the right dose for adequate symptom control,
And whether they are medicated for enough hours in the day (and seven days a week).
When working with clients, I take into account their experience of medication onset and offset, symptom improvement, medication adherence, and side effects. By optimising treatment, we can address not only the core symptoms of ADHD but also associated features like emotion regulation, binge eating, skin-picking, overspending, and drug use, among others. In my experience, stimulant medication can have a transformative effect on clients. It can be truly life-changing and certainly has been in my family.
While the main side effects of stimulants are appetite suppression and sleep disturbance, these are often temporary and not experienced by everyone. It's important to note that there are no common serious long-term negative side effects associated with stimulant medication, and they are not addictive when taken as prescribed (just ask anyone with ADHD who has problems remembering to take a dose). In fact, adults with ADHD who take stimulant medication are at a lower risk of substance abuse compared to those who remain untreated. So, with proper monitoring and support, stimulant medication can be an effective and safe option for managing ADHD symptoms.
It can take a number of months (or years) to get medications right. And even then, the formulation or dose will likely need to change in response to age, environmental demands, pregnancy and childbirth, and menopause. But, they are worth it!
Here's an excellent one-hour podcast about ADHD meds and how to optimise them, presented by ADHD expert psychiatrist Dr William Dodson.
Here's an equally excellent one-hour podcast about ADHD meds in children, presented by ADHD expert developmental pediatrician Dr Walt Karniski.
Clinical psychologist Dr Thomas E. Brown discusses how to optimise and troubleshoot stimulant medication: The ADHD Medication Stopped Working! How to Troubleshoot Treatment. Note that many of the medications in this article are not available in NZ, so compare it to the medications listed in this blog post.
This article: What Are the Long-Term Effects of ADHD Medication on the Brain? shows that there are common long-term effects of taking stimulant medication, and they are all positive.
For a deep dive into how stimulant medications differ and their effects at a neurobiological level, I recommend this podcast from Dr Andrew Huberman: Adderall, Stimulants & Modafinil for ADHD: Short- & Long-Term Effects