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.
Bad breath, or halitosis, can be a major problem, especially when you're about to snuggle with your sweetie or whisper a joke to your friend. The good news is that bad breath can often be prevented with some simple steps. Bad breath is caused by odor-producing bacteria that grow in the mouth.