HOUSTON -

The widely prescribed generic blood pressure medicine Metoprolol ER has been voluntarily recalled by Wockhardt Limited.

The drug, manufactured in Mumbai, India, failed a dissolution test. Tests showed the drug didn't dissolve properly in a person's body.

Metoprolol is commonly used to treat high blood pressure but it is also used as a heart medicine, headache medicine and a prescription to treat tremors. The recall affects only the generic form of the medication made by Wockhardt Limited.

Dr. Reeta Achari, a neurologist practicing in Houston, said the drug was on her radar for years before it was recalled. She had a patient end up in the hospital three times while after changing from the brand name prescription drug to its generic form.

"My patient was in the (intensive care unit) with stroke-like symptoms and it took the third admission for us to finally figure out after a lot of detective work that was the only change -- it was her Metoprolol was now generic," Achari said.

In February, Local 2 Investigates exposed how generic prescriptions aren't always the same as brand names. Generics have the same active ingredient as name brand drugs, but they can vary on how much of the active ingredient is in each pill.

Rules with the Food and Drug Administration say generics can have a little as 80 percent of the active ingredient or as much as 125 percent.

"That's a huge difference for any patient to have to deal with in their biological system," said Achari. "I think a lot of doctors have been suspicious that things aren't right when patients are switched to generic. Unfortunately, we've not had a way to monitor it so yet, I applaud the FDA for doing something about it."

Insurance companies often refuse to pay for brand name drugs meaning patients often feel they have no choice but to switch to generics, even if their doctors object.

Achari feels insurance companies sometimes make decisions for patients.

"I think if the physician asks that a patient get brand medication, the insurance company should think about paying for it," she said.

To minimize problems with generic prescriptions, Achari suggests patients ask for something called an authorized generic. Authorized generics are more likely to be the same as brand name prescriptions.

If that is not available, each time you get a refill, ask your pharmacist for pills made by the same company.

Have a story idea for investigative reporter Jace Larson? Email him or send him a message on Facebook.