sasha asked
Hello. I am currently taking Microgestin 1/20 FE tabs (been between Microgestin and Junel for about 3 years) and just began a cycle of dicyclomine 20mg afternoon and night (with meals — for my acute IBS). I am wondering if this new medication could potentially affect my birth control. I have just began to spot about 9 days into my pill pack (i never spot—ever).
Answer
There are no known or documented interactions between dicyclomine (Bentyl) and birth control pills, including Microgestin.
However, a small number of individuals may experience small changes in absorption with other drugs when taking dicyclomine, simply based on how the drug works.
Dicyclomine is an anticholinergic drug, which is utilized for its antispasmodic properties. It exerts a local, antispasmodic effect on the smooth muscle of the GI tract, which results in:
- Decreased gastrointestinal motility (i.e. decreased movements of the digestive system and a subsequent decrease in the movement of the contents in the GI tract).
- Decreased gastrointestinal muscular tone.
The net effect of dicyclomine is reduced intestinal spasms. This can help relieve symptoms of IBS (irritable bowel syndrome), especially IBS-D (diarrhea predominant).
As dicyclomine affects how quickly the GI tract (and the contents of it) moves, it is reasonable to assume that it can affect the absorption and metabolism of food and drugs. The prescribing information doesn't specifically state an interaction with birth control pills, but it does state the following:
"Anticholinergic agents may affect gastrointestinal absorption of various drugs, such as slowly dissolving dosage forms of digoxin; increased serum digoxin concentration may result."
Any change in the absorption of the hormones in birth control pills (increased or decreased) can certainly cause side effects such as spotting and bleeding. An interaction between birth control pills and dicyclomine doesn't appear that common (based on the lack of published data) but could be a possibility as we know anticholinergic drugs (like dicyclomine) can affect drug absorption purely based on how it works.
It is important to discuss the side effects you are having with your doctor. They may recommend separating doses of dicyclomine and your birth control pills or try a different drug therapy altogether.
