Calcium Channel Blockers

Scleroderma is a chronic disease characterized by the over-production of collagen, an essential component of scar tissue, causing the skin to tighten and harden. The formation of scar tissue in various tissues and organs can prevent their normal function and cause permanent damage.

The build-up of collagen and ensuing damage also can result in narrowing of the arteries. This makes it more difficult for blood to flow and results in not enough oxygen reaching tissues.

One of the most common manifestations of this in scleroderma is Raynaud’s phenomenon, in which reduced blood flow to the hands causes them to feel painfully cold and change color. In severe cases, this can lead to the formation of digital ulcers, which are infection-prone sores on the fingers or toes that take a long time to heal due to reduced blood flow.

While there is no cure for scleroderma or Raynaud’s, there are therapies to manage symptoms and improve quality of life. One of the first-line medications prescribed to treat scleroderma and Raynaud’s phenomenon are calcium channel blockers.

What are calcium channel blockers?

Calcium channel blockers are a type of vasodilator therapy. They act to relax the walls of the blood vessels, opening them and improving blood flow. They also help relax the muscles of the heart.

Calcium entering the smooth muscle cells of the artery walls normally lead to the muscle contracting, which causes the artery to narrow and restrict blood flow. By restricting the amount of calcium that can enter the smooth muscle cells, the calcium channel blockers prevent contraction and cause the blood vessels to relax and widen.

The increased blood flow and oxygen supply reduce the frequency and severity of Raynaud’s symptoms and help heal digital ulcers.

Research is ongoing to investigate whether calcium channel blockers also can reduce fibrosis, or the production of collagen directly, by interfering with calcium-based signaling pathways. A recent study, published in the scientific journal Clinical and Experimental Rheumatology, suggested they may not have a significant effect on fibrosis in scleroderma, but more evidence is required to confirm this.

Types of calcium channel blockers

There are many types of calcium channel blockers prescribed for high blood pressure, heart problems, and circulatory disorders.

The most commonly prescribed calcium channel blocker for scleroderma patients is nifedipine. This is the only licensed medication for Raynaud’s in the U.K., but others may be prescribed off-label. They include Norvasc (amlodipine), Plendil (felodipine), Dynacirc (isradipine), and diltiazem.

Side effects of calcium channel blockers

Calcium channel blockers may cause constipation, headaches, palpitations (irregular or pounding heartbeat), dizziness, rash, drowsiness, flushing, nausea, and swelling in the feet and lower legs.


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