In the US, debit card interchange fees are capped at 0.05% + $0.22, since 2010. That was in the Durbin amendment to the Dodd-Frank Wall Street Reform Act.
Credit card interchange runs up to about 2.9%, but that's only on the cards with the most benefits: those that pay the largest percentage back to the cardholder. That's up to 2% back in cash, reward points or miles... plus 90 day accidental damage protection on all purchases, 1 year extension on all product warranties, travel insurance, concierge service, etc.
Interchange fees for the credit cards without rewards programs start at 0.65%.
Repeating what I asked in another comment, it's important to know what percentage of cards have those benefits. If most credit cards in the U.S. and Canada have cash back, miles, or rewards, then it follows that merchants pay 2-3% on most transactions. In my experience in the U.S. and Canada, almost everyone seems to use a cash-back or reward-type credit card.
I'd be surprised if you could even find such a policy.
[1] And, of course, the same "we won't pay for this" cutoffs impose by e.g. UK's NICE board.
The idea that big pharma companies are happily scalping Americans just so they can provide drugs to countries that can't actually afford them is just... absurd.
For GSK: R&D was 15% of their budget, while 'selling, general and administration' was 39%.[1]
[1]http://www.bizjournals.com/triangle/news/2016/07/19/where-gs...
Even without this, drug development cost doesn't get anywhere close to accounting for the whole cost difference.