It's also a good idea to take a prescription copy (or e-mail it to yourself) in case you need to purchase a replacement for any reason whilst travelling.

In some countries you may be able to purchase without a prescription at a pharmacy (usually "first class" pharmacy or similar with a pharmacist on duty) if you know the generic medication and dosage - but be aware some countries use different names* for the same drug; in some you may be required to show a prescription - and it can be useful in Customs and / or Security.

*E.g. "acetaminophen" may be "paracetamol" in many Anglophone countries, etc.

I carry my prescription for my toothpaste for when I travel outside the US and Canada. I once had my toothpaste stolen from me by the CATSA contractors, who claimed my "prescription was out of date" (despite not needing to show one at all under Canadian law) and got a sincere apology from Ottawa and an offer to send me a check. I was treated gruffly at SYD and the clerk demanded to see my passport to match to my script, but was allowed to go

You are technically supposed to unpack the medically necessary liquid. I usually take my tube out and put it next to my freedom baggie. Sometimes, I get an incredulous TSO who doesn't get that you need prescriptions for certain dental items, but mostly it just goes on by without a bother.