Merck & Co.’s recall of its Vioxx painkiller surprised pharmacies in America and Canada, leaving them unprepared to handle questions from concerned patients and doctors looking for alternatives and trying to get information about possible reimbursement.

“Usually they [Merck] beat the news but all I know is what I heard on the radio,” said a pharmacist at Inman Pharmacy in Cambridge, Mass., Mike Reppucci.

Mr. Reppucci said Merck, the second largest American drug maker, didn’t contact him.

The company withdrew the drug after a study showed patients taking Vioxx for more than 18 months faced twice the risk of a heart attack compared with those taking a placebo. About 2 million people are taking Vioxx for ailments such as arthritis and migraines, and 84 million have taken it worldwide since 1999, Merck said on a conference call announcing the recall.

“I haven’t gotten any call on it yet,” said a pharmacist at the Medicine Shoppe in Monroe Township, N.J., Jennifer Deo. “I’m sure I’m going to hear something about it. If not, I’ll be surprised.”

The U.S. Food and Drug Administration issued an advisory, urging Vioxx users to consult with a doctor about alternative medications. The agency also plans to seek more information about possible heart risk for other drugs in this class, known as Cox-2 inhibitors.

Information from Merck is crucial to pharmacies, said Karen Reed, a pharmacist at a Wal-Mart in Beckley, W.Va.

Depending on what Merck tells them, pharmacists may either have to collect outstanding quantities of the medicine or just instruct patients to destroy it, Ms. Reed said.

In the meantime, Ms. Reed said patients should contact their doctor or their pharmacists both to get further instructions and to get an alternative for Vioxx.

Jean Coutu Group Inc., Canada’s second-biggest drugstore chain, hasn’t received any instructions from Merck on what the chain should be doing, said a spokeswoman for the Longueuil, Quebec-based company, Helene Bisson.

Jean Coutu is asking pharmacists to use their judgment and to “ideally” not fill any prescriptions for Vioxx. The company has received some calls from customers this morning.

Walgreen Co., the largest American drugstore chain, is pulling and quarantining Vioxx and encouraging patients to contact their physicians regarding other drugs that can be prescribed instead, said Carol Hively spokeswoman for the Deerfield, Ill.-based company.