Wednesday, September 29, 2010

Atomoxetine for ADHD

 Atomoxetine (Strattera) is one of the pharmacological options for treating ADHD symptoms (attention or concentration problems, hyperactivity, impulsivity) in children and adults.  I think it is a good drug, quite safe, quite effective.  It is not likely to help with mood or anxiety symptoms.  Its effect is probably not quite as robust, for most people, compared to stimulants, but it has the compelling advantage of working continuously throughout the day, instead of wearing off (as the stimulants do) after a few hours.  It takes at least 2 weeks of daily dosing for it to work, which differs from the immediate effect of stimulants. 

While it has only a 5-hour half-life in the body, it probably works just as well if dosed once-daily compared to twice-daily.  Side-effects are usually quite mild, including possible dry mouth and reduced appetite.  

It is quite expensive, and is not covered well by medication funding plans in BC.

Here is a brief survey of some of the research literature about atomoxetine that I found interesting:
This 2010 article demonstrates that once-daily atomoxetine is superior to placebo for treating adult ADHD symptoms, over a 6-month follow-up period.   Treated patients typically had about a 30% reduction in their symptom scores.  Doses were about 80 mg/day.
This is an important study, with 4 years of follow-up, treating adult ADHD patients on an open-label basis.  The medication was tolerated well, again with ADHD symptom reductions of about 30%.  Depression and anxiety symptoms were not affected.  I tried unsuccessfully to find a clear statement about average doses used in the study; the dosing regime was similar to other studies, with a maximum of 160 mg/day.   From the authors' previous paper on the interim results of this study, the mean dose was about 100 mg/day, the median about 120 mg/day.  So these are higher doses than in some of the other studies, which typically had 80 mg/day dosing.
This was a 6-week open study, showing that adults with "atypical ADHD" showed improvement with atomoxetine treatment, doses averaging about 80 mg/day.
This is an important 2008 meta-analysis, comparing effect sizes of different therapies for adult ADHD.  Short-acting stimulants were best; long-acting stimulants similar (no advantage--if anything, not quite as high an effect size compared to short-acting stimulants); non-stimulants such as atomoxetine significantly helpful, but not quite as large an effect size as stimulants. study shows modest but significant improvement in quality-of-life ratings for adult ADHD patients treated with atomoxetine 80 mg/day for 6 weeks.
This study shows reduction in high-risk behaviours in adolescents treated with atomoxetine over a 40-week period.  Looking quickly at the results, I see significant differences between atomoxetine and placebo, but the absolute differences were quite modest in size (typically about a 10% change).  Also the study design has a variety of weaknesses.
This is one of many studies showing that atomoxetine does not help with depressive symptoms.  In this case, it was used as an adjunct to an SSRI.
This study showed no improvement in cognitive function in patients with schizophrenia treated with atomoxetine over 8 weeks.  There were no adverse psychiatric effects, however.   This is an important area to study, to determine if ADHD treatments such as atomoxetine are psychiatrically safe for those with other major mental illnesses, such as schizophrenia or bipolar disorder.
This 2010 article from Neurology shows that atomoxetine is not useful for treating depression in Parkinson Disease patients.  I find this type of study useful, to look at psychiatric symptoms in medical illnesses.  In such situations, the biological impact of the treatment often seems more clear to me, perhaps with fewer confounding psychological factors.    The study did find that patients treated with atomoxetine (target dose 80 mg/day) had significantly less daytime sleepiness, and significant improvement in "global cognitive function."
This similar study shows a possible improvement due to atomoxetine treatment--averaging about 90 mg/day--of executive dysfunction in Parkinson Disease patients.  I note also that there was a reduction in other symptom domains, such as apathy and emotional lability; these problems can be difficult to address in those with mood disorders.
Here's another interesting study, using atomoxetine to treat sleep apnea patients, averaging about 80 mg/day over 4 weeks.  The atomoxetine did not help reduce apnea, but it did significantly reduce subjective sleepiness.   There are only a couple of fragmentary mentionings of atomoxetine in treating narcolepsy, another disorder of excessive sleepiness; here is one case report: Excessive sleepiness is another challenging symptom I see a lot of in young adult depression; antidepressants often don't help with the sleepiness, and tolerance tends to develop for stimulants.  So atomoxetine may be another useful option. 

1 comment:

Jenna said...

my husband is on Atomoxetine 40mg for about a year now & he seem to feel better now.. No depression & no side effects... But I'm afraid whether he will get used to the drug & he won't be able to get off it...