His announcement came amid warnings from opposition politicians that the Health Department has not thought through the new drug plan and the result could be higher prices or medications not being available when needed.
Horne said that won't happen.
"There are no categories where there are not listings available to fill prescriptions today, and anyone who is telling people something to the contrary is not telling them the truth," Horne told reporters.
As of May 1, the province is cutting in half what it pays for generic drugs. The payout will drop from 35 per cent to 18 per cent for a generic drug compared with the cost of an equivalent brand name medication.
The province said this is a reasonable adjustment to the funding model, will lower costs for consumers and free up an additional $90 million to reinvest in health care.
Pharmacists have said the cut could severely impact their bottom line and lead to layoffs or even pharmacy closures.
Horne said the $40 million is to address those concerns.
Some of the money will compensate pharmacists who bought medications at the old price but will be subject to the new lower fee as of May 1.
Starting next week, the province will also reinstate for one year a $1 payout per prescription.
There will be cash to train pharmacists to perform a wide range of billable tasks introduced last year to give them a larger role in patient care. Those duties include renewing prescriptions and crafting a patient's drug management plan.
There will be $10.6 million over two years to try to keep the doors open on rural pharmacies, which are considered particularly vulnerable due to comparatively smaller customer bases.
"I think what we've done today will help in the transition," said Horne, though he conceded, "I obviously can't make a commitment that we will make every pharmacy whole. They practise in very different situations."
Opposition leaders said they're concerned that the pace of change is too quick and that drug suppliers are reacting by hiking the prices for other drugs or simply not supplying a medication altogether, such as penicillin.
"We're going to see drugs delisted without having an alternative. We're going to see patients paying more out of pocket for their drugs, and we're going to start seeing pharmacy closures," said Wildrose Leader Danielle Smith.
NDP Leader Brian Mason said: "We do support lower drug prices, but the government has to move very carefully to prevent unintended consequences which might mean the withdrawal of low-cost drugs from the market if they can't earn sufficient (profit) margin."
Liberal Leader Raj Sherman said the drug changes and changes to billable pharmacist responsibilities need to be better co-ordinated.
"You can't simply cut their ability to earn an income on one hand and then try to make something up along the way to lighten the burden. This has to be phased in," said Sherman.
Horne said Albertans can get penicillin, and any other required medication if need be, and said the province will work things out with drug manufacturers.
"A lot of these things, when you first announce them, you encounter push-back. And you've got to expect that," said Horne.
"I'm experiencing push-back now from large drug companies, but we know that we've got an obligation to use every health-care dollar the very best way we can use it."