Any good doctor will know about a drug's side effects, both brand names and generics before they prescribe it. But a doctor may have no idea that your medication tastes like fish.
A group of family physicians in Georgia were surprised to learn that many of their diabetes patients had stopped taking a well-known medicine called metformin because it smelled like "dead fish," according to a clinical observation published Monday in the Annals of Internal Medicine.
Now these doctors want to warn other physicians to be on the lookout for stinky drugs.
"A physician may prescribe a drug and as far as seeing the drug, they may never have seen the tablet before and certainly never tried smelling it," said J. Russell May, a co-author of the clinical observation and a professor at the University of Georgia College of Pharmacy in Athens. Ga.
Local pharmacists, not doctors, are the professionals who routinely have contact with prescribed medication, said May. As a result a doctor may be clueless that the reason their patient nauseous is because the drug is hard on the nose, not hard on the stomach especially because the typical side effects of metformin include nausea as well as diarrhea and flatulence.
When Doctors Don't Know Your Drug Smells
Aside from wasting time, May explained the miscommunication could be hurting patients who stop taking medicine to control their insulin levels.
"It's actually crucial -- metformin is a drug that helps the body handle sugar," said May. "Our concern was that this is an easily preventable problem."
For instance, May said his colleagues patients stopped taking their medication because they assumed the fishy smell meant the drugs had "gone bad." May described metformin 's odor as "the inside of the inner tube mixed with fish."
But if doctors knew the medicine smelled ahead of time, May said they could have counseled their patients not to worry about a reeking bottle of drugs.
Drug experts said several other stinky drugs could result in similar problem.
Foul Smelling Drugs Means People Stop Medication
"While I am not aware of any studies that have assessed adherence in patients that take medication that has an offensive taste or odor, I have no doubt that this has an effect on compliance," said Timothy J. Warner, the associate director of pharmacy at the University of Rochester Medical Center in Rochester, N.Y.
In Warner's experience, he's heard that the blood pressure drug diltiazem smells "strongly like plastic," the diuretic Spironolactone has a "minty, menthol smell," and that the antibiotic cephalexin simply has "an awful smell."
"Despite the problems with the taste or odor of medications, patients need to understand the importance of taking their medication as prescribed," said Warner. "If the odor and taste are so bad that it is affecting how they take the medications, they should discuss this with their provider to see if other options are available."
Which Drugs Really Stink?
Warner also suggested that pharmaceutical manufacturers should be aware of smells so they can design tablets and pills that can mask odors.
Indeed, the public certainly has encountered enough stinky drugs.
Alberta Brabitz, of Melbourne Fla., said she won't stop taking her smelly medication, but she wonders why it has to be so smelly. "I take Benicar for high blood pressure and it smells just like sour milk," Brabitz wrote in an e-mail to ABCNews.com.
Ellie, from Rochester, New York, said she can't stand the taste of her generic Xanax, "I don't place it on the center of my tongue and drink water quickly, I'll get this horrible, like bitter and sour taste that lingers," she wrote in an e-mail form to ABCNews.com. Ellie refrained from giving her last name.
Parents who have to deal with rank-smelling medications have twice the struggle.
"My son, Will, who is 11 years old, underwent a bone marrow transplant in June 2009 to treat his severe aplastic anemia. Now he is on an immunosuppressant medication, cyclosporine, that tastes and smells like skunk!," wrote Rebecca Crisler, of Albuquerque, N.M. Crisler said many kids in the bone marrow transplant unit struggle to take the medicine.
"He bravely takes it each day, but it is disgusting!" she wrote.
Drugs Become Ineffective if They Are Hard to Swallow
"Any medicine with an undesirable taste or smell is usually associated with poor compliance," said John Forbes, of the American Pharmacists Association. Forbes said poor compliance -- meaning patients don't take their medicine -- is very common for children taking oral solutions such as the antibiotic Augmentin.
"Fortunately, there are ways to circumvent this problem. Most pharmacies have the ability to flavor an oral solution to increase palatability and compliance," said Forbes.
Forbes also pointed out that not all metformin pills will have the fishy smell, and some generic brands are particularly more pungent than others. "This complaint is uncommon in patients who take brand name metformin, which may be manufactured with an outer coating that masks the poor smell," he said.
Bristol-Myers Squibb (BMS) sold metformin as Glucophage and Glucophage XR (extended release), before generic forms appeared.
"BMS is aware that the inherent characteristics of metformin have been associated with a mild odor upon opening of the bottle, so these type of reports are not unexpected. It's important to note there has been no correlation between an odor and the efficacy of metformin which has been on the market in the US since 1995," BMS spokesman Ken Dominski said in a statement to ABCnews.com. "Metformin continues to be the backbone of type 2 diabetes therapy in the US and has helped millions of people worldwide to manage their disease."
When asked about metformin's smell, the U.S. Food and Drug Administration pointed out that odor often has nothing to do with the quality of some drugs.
"The FDA is aware of reports regarding a strong odor associated with this product. However, these types of odor or taste complaints are not necessarily indicative of a drug quality or safety concern; often times, a bad odor or taste can occur as a result of the chemical composition of the drug product itself," FDA spokeswoman Shelly Burgess said in a statement to ABC News.
"The FDA evaluates drug quality complaints, including those concerning bad odor or taste, that are received through our drug quality reporting system to determine if a drug safety concern exists," she added.