Bentyl is classified as an anticholinergic medication, because it reduces the effect of the neurotransmitter acetylcholine within the body. This diminished action of acetylcholine results in a decrease in muscle spasms and secretion of mucus. Unfortunately, in addition to bringing about IBS symptom relief, Bentyl’s effect on the action of acetylcholine also can bring about a whole host of unwanted side effects.
Side Effects of Bentyl
The anticholinergic effect of Bentyl can affect systems throughout the body. The most commonly reported side effects include:
Blurred visionConstipationDecreased sweatingDecreased urinationDizzinessDry mouth
Other side effects may include loss of appetite, tingling, headache, drowsiness, or weakness.
Bentyl may also cause more serious side effects, such as confusion or falling. It can produce mood swings and visual or audible hallucinations, as well as skin side effects such as hives or itching.
For these reasons, older adults are cautioned that Bentyl may not be appropriate for them. To avoid side effects, however, Bentyl can sometimes be quite helpful in lower doses, especially for women at a dose of 10 mg. In addition, if dosing is limited to once or twice per day, side effects can be reduced.
Is Bentyl Effective?
Although Bentyl is a frequently prescribed medication for IBS, there is a glaring lack of research regarding its effectiveness. Research reviews, including one by the American College of Gastroenterology in 2014, found only one clinical study that assessed the effectiveness of Bentyl in reducing symptoms. This study was from 1981, showing how sparse research is in verifying whether the drug is effective. The results indicated that Bentyl was superior to placebo in reducing abdominal pain and tenderness, as well as improving bowel functioning and overall IBS symptoms. The downside was that approximately 68 percent of patients experienced unpleasant anticholinergic side effects.
A 2014 review noted that, of the antispasmodics, peppermint oil has been well studied and is generally effective and well-tolerated with few adverse side effects. However, unlike Bentyl, it is not regulated by the FDA, since it is sold as a supplement.
How to Take Bentyl
Bentyl comes in several forms—as a capsule, tablet or syrup. It is always taken by mouth. Be sure to follow your healthcare provider’s instructions carefully regarding when to take it. Your healthcare provider may start you off at a low dose and then gradually increase your dosage.
Typically, Bentyl is to be taken several times during the day at spaced-out intervals. Your healthcare provider may recommend that you take Bentyl 30 to 60 minutes before eating.
