Amantadine for ADHD & Irritability
Amantadine is a medication used as an anti-viral medication since the 1960’s, and continues to be used to help treat the flu. It has also been improve focus, impulse control, and even mood swings related to ADHD and disruptive mood dysregulation disorder. It tends to be better tolerated than stimulants when used to treat ADHD, although it is still considered “off-label” (not FDA approved), as there have not been enough double blinded studies to get it approved. This is likely because it is generic, so there is no financial incentive for a drug company to pay for these expensive studies.
What is the mechanism of action for Amantadine in ADHD?
The effectiveness of amantadine results predominantly from this inhibition of NMDA receptors and its ability to stabilize the glutamatergic system. It is thought to be neuroprotective as well.
How is Amantadine dosed in ADHD in children?
For best results, it is recommended to start amantadine at a low dose of 25 mg/day and increase gradually by 25 mg every 4–7 days until a therapeutic response is obtained, with an average dose of 100 to 200 mg/day but not exceeding 300 to 400 mg/day. In general, 100-150 mg depending on weight (100 mg/day for <30 Kg and 150 mg/day for >30 Kg) is our goal dose.
Amantadine only comes as a syrup (10 mg/ml) and 100 mg capsules.
How long does Amantadine last after a patient takes it?
Amantadine usually lasts long enough to just take in the morning. However, it is possible that some will excrete it faster than others, or simply need a booster dose in the afternoon (3:30pm or so) to help keep the concentrations in the brain higher.
Studies do show that it is better to take amantadine daily and the benefits accrue over time, rather than to take it “as needed”, as is sometimes done with stimulants.
How does the efficacy of Amantadine compare to stimulants, like Ritalin/methylphenidate?
It is not quite as effective, but it comes very close, and often with less side effects.
https://clinicaltrials.gov/ct2/show/NCT01099059
What other benefits does amantadine have?
It has been shown to benefit anxiety, OCD, and depression. It also improves neuroplasticity in those with brain injuries.
It is thought to be safe for longterm use.
Here is a link to a relevant, good review article:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3565716/pdf/ccap22_1p0055.pdf
What are the common side effects to Amantadine?
The side effects, on average, are much less intense than stimulants. But, some are similar including:
-Decrease in appetite
-Insomnia
-Use with caution in those with reduced kidney function, as it is excreted by the kidney
-Use with caution in those with glaucoma, as it can have some anticholinergic side effects.
Is it OK to take while getting a viral vaccine?
Since amantadine is an anti-viral, it should be held if the patient is receiving a live attenuated vaccine, as it may limit the efficacy of the administered vaccine. Here are examples but be sure to check with your doctor when scheduling a vaccine:
-Measles, Mumps, Rubella (MMR combined vaccine)
-Rotavirus
-Smallpox
-Chickenpox
-Yellow fever
