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 most influential factor for most people in managing ADHD symptoms. But here's the thing - as with all medications, stimulant medications don't work the same for every person, which means an individualised approach to treatment is required. That's why understanding what is available when talking with your prescriber about treatment options can be helpful. That's what this post is all about.
Disclaimer: I am not a medical doctor and cannot prescribe any medications. My knowledge comes from reading psychopharmacology textbooks, drug information sheets, research articles, and listening to podcasts and webinars from ADHD expert psychiatrists and pediatricians. There are links at the bottom of this blog to information presented or approved by medical doctors.
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 differentially in the brain.
Below is a list of the stimulant medications available in New Zealand. Each name contains a link to the Medsafe data sheet for this medication. This information is provided to Medsafe by the medication manufacturers. Medsafe also offer Consumer Medication Information documents, which can be found by searching for the medication name on the Medsafe website.
Methylphenidate formulations:
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 approximately four hours later once an outer coating dissolves in the gut. Rubifen SR is a slower-acting release in tablet form.
Click here for a video that shows the sophisticated way that Concerta releases methylphenidate in the gut.
Dexamphetamine:
Immediate release: 3-4 hours action with quick onset and offset. Generally trialled when methylphenidate formulations have either not alleviated symptoms or have produced intolerable side effects. The brand of dexamphetamine available has changed a few times in recent years, and is currently changing, so the Medsafe information sheet linked may not necessarily reflect which brand is being used at the time you may be reading this. I will update the link when I have more information about which brand is being used.
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, it is not funded by Pharmac funded, therefore it does cost more - $100 dollars or more a 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 an improvement for some who respond best to an amphetamine preparation, and I look forward to the day when it is funded by Pharmac.
ADHD medication can be customised 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.
GPs in Canterbury are advised to begin treatment for ADHD with the shortest-acting medication, at a dose increasing weekly. For most people, they are likely to notice increasing treatment effects with increasing dose. Managing ADHD symptoms with fast-acting medication can be challenging, as it requires multiple carefully timed doses throughout the day. In Canterbury, GPs are recommended a switch to a longer-acting formulation soon after the fast-acting trial, for easier management of symptoms.
Perhaps in part because of the smaller number of formulations available, dexamphetamine is not typically used as a first-line treatment in New Zealand. In other regions, like the US and Australia, amphetamine preparations are more equally used due to funding and the number of available options. For example, in the US they have various formulations of Adderall, which is a mixture of four amphetamine salts. They even have stimulant options in patch, gummy, and liquid forms - imagine that!
By optimising treatment, the core symptoms of ADHD and associated features can be greatly improved. In my anecdotal experience, stimulant medication can have a transformative effect. It can be truly life-changing for some. So, it's worth not giving up if things don't go well initially, and having open communication with the prescriber.
Persistent side effects should be discussed with a person's GP, as a change in chemical or formulation might lead to improvement. 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 - swallowed and at the right 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 may need to change in response to age, environmental demands, pregnancy and childbirth, and menopause.
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? may answer a few questions.
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
