Here is a collection of user reviews for the medication Toprol XL sorted by most helpful. See User Reviews. Report Problems to the Food and Drug Administration. You are encouraged to report negative side effects of prescription drugs to the FDA.
1 Persistent bad breath or a bad taste in the mouth can also be one of the warning signs of gum disease; which is caused by plaque.  Dry mouth. This occurs when the flow of saliva decreases and can be caused by various medications, salivary gland problems or continuously breathing through the mouth.
Symptoms & Signs. Bad breath, medically known as halitosis, is a common problem. Bad breath is usually simple and preventable. Dietary factors as well as tobacco and alcohol use may all be factors in causing bad breath. Poor oral hygiene, gum disease, tooth decay, or mouth infections can also be causes of halitosis. Infections in the lungs, sinuses, or airways can also cause bad breath due to the presence of nasal secretions that may drain into the mouth. Chronic postnasal drip, for example as occurs with sinus infections, can be a cause of bad breath. Coughing up sputum from lung infections can also cause bad breath. Dry mouth (xerostomia) can be a side effect of certain medications, increasing the tendency to develop bad breath.