Gastroesophageal reflux disease, or GERD, occurs when a weakened valve called the lower esophageal sphincter allows stomach acid and sometimes bile to flow upward into the esophagus, irritating its delicate lining. Unlike occasional heartburn or acid reflux, GERD is diagnosed when these symptoms occur at least twice per week. Certain medications, including calcium channel blockers commonly prescribed for high blood pressure, angina and migraines, can worsen GERD because they interfere with the function of the lower esophageal sphincter.
Calcium Channel Blockers
Calcium channel blockers, also known as calcium antagonists, inhibit calcium ions from entering channels in membranes of calcium-sensitive cells. The net effect is to relax muscles and quiet nerve signaling, which opens up the blood vessels and decreases blood pressure. However, calcium channel blockers also affect smooth muscles in other parts of the body, such as the esophagus. When the lower esophageal sphincter relaxes and fails to close tightly, stomach contents can wash back up into the esophagus, causing the symptoms of GERD.
Drugs
Examples of calcium channel blockers include the drugs nifedipine, amlodipine, felodipine, isradipine, diltiazem and verapamil, among others. When prescribed for people with high blood pressure or angina, these drugs can also worsen GERD. In fact, calcium channel blockers are sometimes prescribed specifically to relax the esophagus, for patients who have esophageal spasms or whose lower esophageal sphincter is too constricted to allow normal swallowing, a condition called achalasia.
Clinical Study
In their July 2007 paper in the "British Journal of Clinical Pharmacology," Dr. Jeff Hughes and colleagues reported their findings of patients prescribed calcium channel blockers for hypertension. After taking the drugs, 35 percent of the patients who formerly had no gastrointestinal issues developed acid reflux symptoms. The majority of patients who already suffered from acid reflux symptoms got worse after taking the calcium channel blockers, with 59 percent reporting more frequent and more severe episodes. Amlodipine worsened symptoms in 61 percent of patients using it, while only about 12 percent of patients taking diltiazem reported an increase in their reflux symptoms.
Alternatives
Nifepidine, along with amlodipine, felodipine and isradipine, are in a class of calcium channel blockers called dihydropyridines, while verapamil is a different class of calcium channel blockers called diphenyalkylamines, and diltiazem is a benzothiazepine derivative. Patients who find that GERD symptoms worsen while taking a particular calcium channel blocker, or those who develop GERD while taking these drugs, might want to try a different class of drug that controls their blood pressure or heart condition while sparing their esophagus. Hughes concludes that diltiazem is the least likely of the calcium channel drugs to cause or worsen GERD symptoms.
Expert Insight
Hughes urges doctors to be aware of the potential side effects of calcium channel blockers on the function of the lower esophageal sphincter. He suggests that doctors avoid prescribing calcium channel blockers for patients with GERD, and withdraw them from patients who develop GERD symptoms while taking them in favor of other types of drugs to treat hypertension.
References
- Mayo Clinic: GERD
- Mayo Clinic: Calcium Channel Blockers
- Merck Manual: Motility Disorders
- "British Journal of Clinical Pharmacology"; Jeff Hughes, Judith Lockhart and Andrew Joyce; Do Calcium Antagonists Contribute to Gastro-oesophageal Reflux Disease and Concomitant Noncardiac Chest Pain?; July, 2007.
- Merck Manual: Calcium Channel Blockers for Hypertension
