Canadian Pharmacies do not carry it the last I looked. Call Highland Specialty Pharmacy located in Mississippi 855-894-4441. Cost is around $68.00 per month. There are also coupons you can print from Tirosint's website to help with the co-pay.
Have you checked to make sure you can buy it from Canadian pharmacies? When I took it a few years ago and ran into that problem, it wasn't available via Canadian pharmacies...
I'm not "allergic" to the fillers in Synthroid or other synthetic T4 medications, but I did much better on Tirosint until it got so expensive I could no longer justify paying $150/month for my thyroid medication (that's what it was back then).
I switched to Levoxyl, which many people who don't do well on other T4 medications, typically, tolerate well. I've been on it since August of 2014 and am doing well with it. If you haven't tried that particular brand, you might look into it.
It's important to note, as well, that different manufacturers of each generic uses different fillers/binders, so there may be a generic out there that you could tolerate; you just have to find it, which could be like finding a needle on a haystack, and make sure your pharmacy never fills your script with pills from a different manufacturer.
Other options are look at a website called GoodRx and check the cost of Tirosint there. It's a website on which you get coupons that will discount the cost of many types of drugs. The discounts are different for all areas...
For instance, 90 Tirosint gelcaps at the 88 mcg I'm on would cost me $489 at CVS cash price, but with a GoodRx coupon they would cost me $389. Different stores have different prices... for instance, with a coupon, the med would cost me $394 at Walgreen's and $405 at Walmart... In some cases, it's not a huge savings, but it is a savings. Prices are different all over the country, apparently.
Another option is to contact the manufacturer... they have programs that provide the medication at low/no cost to some people. I never qualified; in fact, I found out that part of the reason my cost (and others like me) was so high is because we could afford to pay for our medications, so we helped subsidize the programs for those that can't pay... I don't mind helping others out, but when the price gets so high that I can't afford it, it's time to call a halt. Anyway, you can contact the manufacturer and see if you do qualify for any of the programs. Even if you don't, they used to have coupons with which you could get money off your prescription. When I was on Tirosint, the coupons were, typically, worth $10-$20, but if the medication is that much more expensive now, maybe the coupons are worth more... Anyway, it might be worth contacting the manufacturer, if for no other reason than to let them know the cost is getting out of reach... I did and they practically begged me to stay on it, but offered me nothing to do so... I simply couldn't afford it.
Another option is to go compounded medication that takes out the fillers you're allergic to and puts in something you an tolerate. These are, typically, more expensive than regular generics, but, not as expensive at the Tirosint and you can get something that works for you.
Talk to your doctor about the different options in medications and see what you can work out.