Read up more on Strattera. It can take 2 to 4 weeks to take effect. 40mg is a middle dose. Guidelines say "Based on weight, 0.5 to 1.5mg/kg, target 1-1.4 mg/kg" for the dose. So yes, you may want to up the dose.
From this source - http://www.leeheymd.com/charts/adhd_1.html
Strattera is a non stim. Drug. Should be no problem taking it . Hope it works for you
My doc is 87 years old, he didn't even know what strattera was before I researched it. He told me I never heard of that. He wanted to start me on 100 mg of strattera but I told him 40mg to start was better. He seemed like he didn't know what the heck he was doing. Many times the patient knows more than the doctor.
If you have a doctors prescription for medication and you get fired for taking what your doctor recommends - I think you would have serious grounds for a lawsuit. There is a big difference between a speed addict and someone with ADHD. You really FIRST need to find out what your company policy really is about legally prescribed medication.
Second, all docs start you off on a low dose and wait to see how you respond. Sounds like you body has adjusted and the dose needs to be upped. And you should check into the extended release versions.
What you need to do (beside really check on company policy) is talk to your doc. Maybe do that first since he may know more on this subject then I do. Also let him know that the meds are not working now. Hope this helps.