Diltiazem is a calcium channel blocker frequently prescribed to manage various cardiovascular conditions. Brand names include Cardizem, Dilacor, and Tiazac. It is primarily used to treat high blood pressure, angina (chest pain), and specific abnormal heart rhythms, such as atrial fibrillation. Like all medications, diltiazem can produce side effects.
Diltiazem’s Effect on Bowel Movements
Yes, diltiazem commonly causes constipation. Clinical trials and post-market surveillance consistently show that constipation is one of the more frequent non-cardiac adverse effects experienced by patients. The reported incidence varies, sometimes ranging between 2.4% and 9.5%. While frequent, the impact on daily life differs greatly from person to person. For many, the constipation is mild and manageable, but it is a recognized consequence of the drug’s mechanism of action.
The Biological Mechanism of Constipation
Diltiazem’s therapeutic benefit comes from its function as a calcium channel blocker, which inhibits the movement of calcium ions into cells. In the cardiovascular system, blocking these channels relaxes smooth muscles in blood vessel walls, lowering blood pressure and reducing the heart’s workload. This action also extends to the smooth muscle lining the gastrointestinal (GI) tract.
Calcium is necessary for the contraction of all smooth muscles, including the intestinal muscles. These muscles must contract rhythmically in a process called peristalsis to push waste through the intestines. By blocking calcium channels in the GI tract, diltiazem reduces the strength and frequency of these contractions.
This reduced motility means waste moves more slowly through the colon, allowing more water to be absorbed from the stool. The resulting slow transit time and hardened stool directly cause constipation.
Practical Management Strategies
Managing medication-induced constipation often begins with adjustments to daily habits and lifestyle. Increasing dietary fiber is a primary strategy, as this adds bulk to the stool and helps retain water, promoting easier passage. Excellent sources of fiber include fresh fruits, vegetables, whole grains, and legumes.
Adequate hydration is equally important, as fiber needs water to work effectively and soften the stool. Drinking sufficient water throughout the day helps mitigate the drying effect of reduced colon motility. Engaging in regular physical activity, such as a daily walk, also stimulates intestinal muscles and encourages normal bowel function.
If lifestyle changes are insufficient, over-the-counter (OTC) options may be considered after consulting a healthcare provider. Bulk-forming laxatives, such as psyllium, work similarly to dietary fiber by absorbing water and increasing stool volume. Stool softeners add moisture to the stool, making it easier to pass. In persistent cases, an osmotic laxative, which draws water into the colon, may be recommended for temporary use.
Recognizing Serious Symptoms
While constipation is a common and usually manageable side effect, certain symptoms require immediate medical attention. Contact a healthcare provider promptly if you experience severe, continuous abdominal pain or cramping. Persistent nausea or vomiting that does not resolve is also a warning sign.
An inability to pass gas or stool for several days could indicate a significant blockage. Any observation of blood in the stool, or stool that appears dark and tarry, must be reported immediately. Never stop taking diltiazem abruptly without first consulting the prescribing physician, as discontinuing the medication without guidance can lead to dangerous changes in your blood pressure or heart condition.