Which of the following is a common side effect associated with calcium channel blockers?

Calcium channel blockers are a class of medications primarily used to treat high blood pressure and certain heart conditions. A common side effect associated with these medications is constipation. This occurs because calcium channel blockers can affect the smooth muscle in the gastrointestinal tract, leading to decreased bowel motility. As a result, patients may experience difficulty in bowel movements or constipation.

In contrast, the other options do not commonly associate with the typical side effects of calcium channel blockers. For instance, while increased heart rate might occur in some scenarios, calcium channel blockers are more often associated with decreasing heart rate as they relax the blood vessels and reduce the workload on the heart. A skin rash can be a side effect of many medications, but it is not a standard reaction to calcium channel blockers. Weight gain is not commonly linked with this class of drugs and may be influenced more by lifestyle or other medications.