Strattera/atomoxetine

[HanDor]

My 15 yo son just began straterra/atomoxetine. How long has it taken for your body to get used to the medication? He is complaining he's so tired.

[Hidden]

Every child is different and what I noticed when my son was started on Atomoxetine- he wasn’t tired at all and it didn’t affect him in any way (no sleep disturbance, no changes in appetite, no nausea or vomiting). On the other hand there is a boy in his class and he’s on Atomoxetine too- he has suffered from severe sedation when starting medication and it continued for about 6 weeks until his body got used to it. His parents persevered and now his body got used to it they are very happy with how his symptoms are controlled. This boy also tolerates much lower dose than my son. As I say- every child is different and reacts differently.For our son it was almost like my husband and I were saying ‘It’s as if medication doesn’t work because we don’t notice anything, nothing bad for sure, we did notice that his mood improved however and he was saying he was happier, his anxiety decreased, he started being more chilled, more relaxed but from my observations not much more focused.’ The symptom reduction came very subtly and at first is was so subtle that I could hardly even notice anything (maybe it’s a placebo effect 😉). Then the realisation came- ‘oh, he’s able to get ready on time in the morning without a drama (on no medication or on Methylphenidate it was not possible, he was a mess in the mornings). Then I realised ‘oh, he’s able to do after school sports clubs at 5pm and still function reasonably well until bed time at 8pm’.

My son was on a low dose Atomoxetine for a good few months (rather than a few days and then immediately whacking it to a maintenance dose of 1.2mg/1kg body weight). His doctor was cautious because I think there is like 10 % population that is super sensitive to this medication and metabolises it quicker so it works much stronger on those individuals. In the UK the tests to establish how a person metabolises medication aren’t widely available but I think in the US it’s a common practice to first test how a person metabolises this particular drug and then straight away you know what dose to set as a ‘maintenance dose.’

Also my son is a poor eater so doctor wanted to see how it would affect his growth and weight gain. On the last medication review we found that within 3 months my son has grown nearly 2 cm and gained nearly 2kg weight so clearly Atomoxetine didn’t affect his growth. His blood pressure and heart rate are normal for his age and he doesn’t t suffer from side effects- so psychiatrist agreed to whack the dose to a ‘maintenance dose’ of 1.2mg/1kg body weight- as in a medication leaflet.

So I am now hoping that within a few weeks we will see also better focus and better impulse control. If not then I think we might ask to try Guanfacine- to see if this would focus him better.

I would say persevere for a few weeks on Atomoxetine, especially as it’s a summer holiday so no pressure with the school. In September look at it again. His body might get used to it.

Also it might be that for him a split dose (half dose in the morning and another half in early evening) will work better and help to minimise the sedation side effect.

[ELucas13]

We gave it a go for about a week and half but my son was very ill on the medication. He would vomit and that wasn't sustainable for us. From what I understand about Stratterra, it takes some time to kick in and adjust, we just couldn't justify the side effects to keep going on my 8 year old son. But, as is the refrain on these forums, every child is different. It may be worth keeping going to see if it will work for your child! I'd expect the side effects to dissipate as his body adjusts.

[Elijah1]

Give him a few weeks. If still tired, he may be one of the 10% or so who are SLOW metabolizers so regular dose causes a higher blood level than expected. If so, the dose can be decreased or split or, as Pattimum wrote, you can do pharmacogenomics testing to find out if he is a slow metabolizer.

[bernerDad]

Elijah is correct about the prevalence of poor-metabolizers in the population (primarily due to deficits in CYP2D6, a hepatic enzyme that catalyzes the metabolism of this sort of drug). But it's uncommon to undergo gene testing to direct management once a med is started because of the time it takes and the weak evidence of meaningful differences in outcome.

However, just because one is a poor metabolizer doesn't necessarily mean they're a poor responder -- it just might take longer to reach steady-state and ultimately show a response. Typically, steady state is reached in several days with this medication and therapeutic response starts after a couple weeks and reaches a maximum in 4-6 weeks.

Strattera is usually given in the morning, but it can be taken at night if it causes daytime fatigue and does not interfere with sleep when taken later. Unlike stimulant medications, this medication works through a longer-term mechanism (though some patients report a short-term "immediate" response as well), so giving it consistently at night should have the same long-term response in terms of controlling ADHD symptoms.

To why your child might be experiencing fatigue right now... this medication (and many oral medications) undergoes what is called first-pass metabolism. This greatly decreases the amount of native compound that enters circulation. Of course, in people with decreased or variant CYP2D6 this amount can be much higher than with typical patients.

It is actually usual for the liver to upregulate production of enzymes when there is a demand, so it might be very possible that your child will adapt very well to this medication given some time. How long? Well, it's variable but on the order of 1-2 weeks at least.

Hope this helps!