Patients should consult their physicians before taking any other medication (either prescription or over-the-counter) or nutritional supplements. Of particular note to individuals taking calcium channel blockers are:

• Other antihypertensives. These include diuretics, beta blockers and ACE inhibitors. In combination with calcium channel blockers, there is a small chance that these medications could produce a severe drop in blood pressure. Still, calcium channel blockers are commonly and routinely prescribed with other antihypertensives. Patients should discuss the risks and benefits of combination therapies with their physicians.
  
  
• Some antiarrhythmics. Medications used to treat abnormal heart rhythms (arrhythmias). Use of CCBs may intensify the effects of these medications.
  
  
• Inotropes. Medications that strengthen the heart’s contractions and are used in the treatment of heart conditions (e.g., tachycardia, heart failure).
  
  
• Corticosteroids. Cortisone-like anti-inflammatory medications used in the treatment of a number of conditions including asthma, skin irritation, nasal congestion and more.
  
  
• Some other medications including those used in the treatment of glaucoma, epilepsy or fungal infections.
  
  
• Over-the-counter (OTC) medications. Patients taking calcium channel blockers for hypertension should avoid OTC products that may increase blood pressure, including those used for appetite control, asthma, colds, cough, sinus problems or hay fever. People should also be careful about using eye drops that treat bloodshot eyes.
  
  
• Alcohol. Drinking alcoholic beverages could also produce a severe drop in blood pressure. Patients on calcium channel blockers should refrain from alcohol use unless otherwise advised by their physician.
  
  
• Grapefruit juice. Grapefruit juice interferes with the liver’s ability to rid the body of some substances. This could lead to a toxic buildup of calcium channel blockers. Patients taking calcium channel blockers may be advised to refrain from drinking grapefruit juice.
  
  
• Recreational drugs, such as heroin, LSD and marijuana. Hypotension may occur with drugs used for erectile dysfunction, since these drugs are also vasodilators.

Calcium channel blockers are often prescribed in combination with nitrates when used to treat angina (a type of chest pain, pressure or discomfort).