What is the major effect of a calcium channel blocker in cardiac contractions?
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Calcium channel blockers (CCBs) are a class of medications used to treat high blood pressure (hypertension). They work by blocking some of the calcium that enters the heart and arteries. Show
You may have heard of calcium as a key nutrient for your bones, but it also plays a very important role in heart function. Calcium moves into the cells of your heart every time it beats, allowing a strong and even squeeze of the muscles to happen. If you have high blood pressure, the force of blood flowing through your arteries is higher than normal. Taking CCBs works by reducing the flow of calcium into your heart and arteries, which helps to:
CCBs are also sometimes called calcium antagonists. They’re as effective as ACE inhibitors in reducing blood pressure. CCBs are available in many forms that you take by mouth, ranging from short-acting dissolving tablets to extended-release capsules. The dosage will depend on your overall health and medical history. Who should use themYour doctor may prescribe CCBs if you have:
Other forms of medication can also treat high blood pressure. Your doctor may prescribe both a CCB and another hypertensive drug at the same time. The 2017 guidelines from the American College of Cardiology recommend the following medications be considered first when treating high blood pressure:
Certain groups of people may especially benefit from CCBs in combination with other medications, including:
Side effectsSide effects of CCBs include:
Certain CCBs can also lower blood glucose levels in some people. Tell your doctor about any side effects you’re experiencing. They may adjust your dosage or recommend that you switch to another medication if the side effects don’t go away, are uncomfortable, or pose a threat to your health. Your doctor will take your age into consideration before prescribing a blood pressure-lowering medication. CCBs are often less likely to cause side effects in people over the age of 65. How they workCCBs reduce blood pressure by limiting the amount of calcium that flows into heart muscle and arterial cell walls. Calcium particles help create the electrical signal that makes the heart contract, or beat. With less calcium flowing into the muscles and arteries, your heart’s contractions aren’t as strong with each beat, and your blood vessels are able to relax. This leads to lower blood pressure. Types of CCBsThe three main subclasses of CCB drugs are based on their chemical structure and activity:
Examples of CCBsDihydropyridinesBecause of the way they work in the body, dihydropyridines are more commonly used to treat hypertension than other subclasses of CCBs. This is due to their ability to reduce arterial pressure and vascular resistance. Dihydropyridine calcium antagonists usually end in the suffix “-pine” and include:
NondihydropyridinesBenzothiazepines and phenylalkylamines fall under a grouping of CCBs called nondihydropyridines. These drugs lower blood pressure but also have other effects on the heart. They’re generally used to treat angina (chest pain) and arrhythmia (irregular heartbeat). Verapamil (Verelan) is one commonly prescribed phenylalkylamine. Diltiazem (Cardizem CD) is one example of a benzothiazepine. Natural calcium channel blockersMagnesium is an example of a nutrient that acts as a natural CCB. Research has shown that higher levels of magnesium block the movement of calcium in the body. In animal studies, magnesium supplementation seemed to be most effective in treating young animals with elevated blood pressure, before they developed hypertension. It also seemed to slow the progression to hypertension. Magnesium-rich foodsinclude:
Ask your doctor whether eating foods high in magnesium will change the effects of the CCBs you’re taking. Interactions with CCBsMedicationsCCBs may interact with other drugs you take, making them less effective or increasing the likelihood of side effects. These include:
Taking CCBs should also be avoided in people with mental health conditions who experience orthostatic hypotension due to their medications. Orthostatic hypotension is a type of low blood pressure that happens when you move from sitting or lying down to standing up. It’s a common side effect of antipsychotic medications. Food and alcoholIt’s generally recommended to avoid drinking alcohol, especially binge drinking, when taking blood pressure medication. You should also avoid taking CCBs and consuming grapefruit products, including whole fruit and juice, at the same time. Grapefruit products interfere with your body’s normal process for getting rid of the CCBs, which could be potentially dangerous if large amounts of the drug build up in your body. Wait at least 4 hours after you’ve taken your medication before drinking grapefruit juice or eating grapefruit. SupplementsCertain supplements may increase or decrease the effectiveness of CCBs. These include:
Outlook CCBs are some of the first medications considered for people with high blood pressure, especially older adults. They’re generally considered a safe and effective drug. Serious side effects are rare with CCBs. If you’ve been prescribed a CCB, try learning about the possible side effects and drug interactions. Report these to your doctor if you experience any symptoms. Be sure to provide your doctor with an updated list of all of your medications, vitamins, and herbal supplements. How does a calcium blocker affect muscle contraction?Excerpt. The calcium channel blockers act by blocking the influx of calcium ions into vascular smooth muscle and cardiac muscle cells during membrane depolarization. Because muscle contraction is largely dependent upon influx of calcium, its inhibition causes relaxation, particularly in arterial beds.
What are the effects of calcium channel blockers?Calcium channel blockers are a group of medications that limit how your body uses calcium. By slowing down how your cells use calcium, these medications can lower your blood pressure, prevent heart rhythm problems and more.
Which of the following is the most common adverse effect of calcium channel blockers?All of these are possible side effects of calcium channel blockers, but the most common side effect is edema. Calcium channel blockers decrease blood pressure by hindering the influx of calcium into myocardial cells. They may also increase the diameter of blood vessels, which always results in decreased blood pressure.
Which outcome is expected with calcium channel blockers?Calcium channel blockers might be expected to have beneficial effects in systolic HF by reducing peripheral vasoconstriction and thereby reducing left ventricular afterload.
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