|What Are Calcium Channel Blockers?
Calcium channel blockers are a group of drugs (also known as calcium antagonists) which are used for treating high blood pressure (hypertension), angina (chest pain in women due to impaired blood flow to the heart) and certain types of cardiac arrhythmia (irregular heartbeats). They may also be used to treat migraines, brain aneurysm complications and Raynaud’s phenomenon (cold hands and feet caused by narrowing of the arteries which supply blood to the area). Calcium blockers block the movement of calcium into the heart and blood vessels causing them to relax. This improves blood circulation, reduces blood pressure and decreases the workload of the heart. There are many different types of calcium channel blockers, from short acting blockers whose effects only last a few hours to longer acting types whose effects take more time to kick in but last for longer. Calcium channel blockers (CCBs) are usually used in combination with other angina or blood pressure medications. The monthly costs of CCBs range from $20 to more than $200.
What Are The Main Types?
Individual CCBs work differently which means a CCB that is taken to treat one condition, will not work for another. There are 3 main groups of CCBs:
Phenylalkylamines: This group includes verapamil. These drugs mainly affect the heart muscle and reduce its workload. They are prescribed to patients who suffer angina attacks, have hypertension or heart arrhythmia. They are not suitable for patients with congestive heart failure or those already taking beta-blockers.
Benzothiazepines: This group includes diltiazem. These drugs relax both the heart muscles and arteries so they can be used for treating angina or hypertension.
Dihydropyridines: This group includes amlodipine and nifedipine. These drugs mainly affect the arteries and cause them to become wider which lowers blood pressure.
Common American Brand Names
|Generic Drug Name
||Cardizem LA; Tiazac
||Procardia; Procardia XL; Adalat CC
||Calan; Verelan; Covera-HS
Many of these medicines are available as low-cost or moderately priced generic drugs through monthly programs offered by chain stores. Stores include Walmart, Target, Kroger, Sam's Club, Walgreens, Kmart and Target. Many store programs have restrictions and membership fees so do make sure they offer your drug and dose before signing up.
Common UK and Irish Brand Names
|Generic Drug Name
||Exforge (in combination with valsartan); Istin; Amlostine
||Adizem; Angitil; Dilcardia SR; Dilzem SR; Dilzem XL; Slozem; Calcicard CR; Tildiem; Tildiem LA; Tildiem Retard; Viazem; Zemtard
|| Felogen XL; Felotens XL; Keloc SR; Parmid XL; Plendil; Neofel XL; Vascalpha; Cardioplen XL
||Adalat; Adipine MR; Adipine XL; Coracten SR; Coracten XL; Fortipine LA 40; Nifedipress MR; Tensipine MR; Valni XL
||Cordilox; Tarka; Securon; Half Securon SR; Securon SR; Univer; Verapress MR; Vertab SR 240
How Do They Work?
How They Work On The Heart
How often our heart beats is controlled by special cells in the body which generate electrical impulses (like cardiac pacemakers). These impulses can be measured by electrocardiogram test (ECG) to ensure that they are functioning properly. As the electrical impulses spread from cell to cell in the heart they are converted into chemical signals. One chemical signal is a rising level of calcium. As the level of calcium in the heart muscle rises, it causes the muscle to contract. CCBs work by blocking the movement of calcium into the muscle cells and in the process cause the heart to slow down and beat less frequently or strongly. Depending on which medication is prescribed CCBs can help alleviate angina symptoms and arrhythmia symptoms (when used to treat arrhythmia they come under the classification antiarrhythmics).
How They Work On Blood Vessels
Blood is carried around the body by our arteries, and the walls of those arteries have a special type of cell called smooth muscle. These cells control the width of the arteries. As the level of calcium inside the muscle cells increase, the artery narrows. This raises blood pressure because blood needs to be squeezed through a smaller, restricted space. CCBs work by preventing calcium entering the muscle cells, so they do not contract. Instead, they say relaxed and the arteries widen (vasodilation). This also helps to reduce symptoms of coronary heart disease such as angina.
Lowering Blood Pressure
CCBs are not usually prescribed as a first line of treatment for high blood pressure. Instead they are normally the second or third option if other drugs such as ACE inhibitors and beta-blockers have failed to reduce levels adequately. CCBs are however considered a first line of treatment (in combination with other drugs) in patients with hypertension who also have angina or high stroke risk factors. They may also be combined with cholesterol drugs such as statins in patients with both high blood pressure and high cholesterol levels. Once you are prescribed CCBs, prepare to stay on them long-term. Some people are tempted to stop taking blood pressure meds when they think their blood pressure is under control. Doing so can put their life in danger.
As with hypertension, CCBs are typically only prescribed as a second or third treatment for angina and generally only in combination with other angina treatments. Usually beta blockers or nitrate medications are considered more effective therapies as well as being more cost-effective. If you are taking CCBs and suddenly stop taking them, do be aware you could experience chest pain.
What If I Am Taking Other Drugs?
Other medications can interfere with the effectiveness of calcium channels, so do be sure to tell your doctor about all drugs, vitamins and herbal supplements you are taking. In particular the following are known to either increase or decrease CCBs effectiveness:
• Other high blood pressure medications such as beta-blockers and ACE inhibitors.
• Antiarrhythmic medications - treatment for irregular heartbeats.
• Digitalis (brand name Lanoxin) for the treatment of heart failure.
• Corticosteroid or cortisone-type drugs.
• Large doses of vitamin D and calcium food supplements.
While taking CCBs you should not smoke. Combining the effects of smoking with CCBs can cause a rapid heartbeat called tachycardia. Also, avoid drinking grapefruit juice as it interferes with the absorption of the medication - increasing the amount of CCB which enters the bloodstream can lead to a sudden drop in blood pressure. Other fruit juices, including orange and tomato juice, appear to be safe.
Interesting Read: Living with Heart Disease
What Are The Side Effects?
Common Side Effects
Swelling in the feet and lower legs
Less Common Side Effects
Very fast (tachycardia) or very slow (bradycardia) heartbeat
Shortness of breath
Constipation (associated more with verapamil)
Rare Side Effects
Jaundice (yellowing of the skin)
Swollen or bleeding gums