Verapamil

High Blood Pressure

Verapamil is used to treat hypertension (high blood pressure). Lowering blood pressure helps prevent serious health complications, such as strokes, heart attacks, and kidney problems. It may be used alone or in combination with other blood pressure medications.

Chest Pain (Angina)

This medication is prescribed to manage and prevent chest pain caused by reduced blood flow to the heart. It is used for several types of angina, including:

• Chronic stable angina: Chest pain that typically occurs during physical activity or stress.
• Unstable angina: Chest pain that may occur at rest or is unpredictable.
• Vasospastic angina: Also known as Prinzmetal's variant angina, which is caused by spasms in the heart's arteries.

Heart Rhythm Disorders

Verapamil is used to treat and prevent certain types of irregular heartbeats (arrhythmias). It helps regulate the heart's rhythm in conditions such as:

• Atrial fibrillation and atrial flutter: It is used to control the heart rate in patients with these conditions.
• Paroxysmal supraventricular tachycardia (PSVT): It is used to prevent and treat rapid heart rate episodes that originate above the heart's ventricles.

Mechanism of Action

Verapamil belongs to a group of medicines called calcium channel blockers. It works by affecting the movement of calcium into the cells of the heart and blood vessel walls. Because calcium is necessary for muscles to contract, blocking its entry causes the muscle cells to relax.

Relaxing Blood Vessels

By relaxing the muscles in the walls of the arteries, verapamil allows the blood vessels to widen. This process makes it easier for blood to flow through the body, which helps lower blood pressure.

Reducing Heart Workload

Verapamil also has direct effects on the heart muscle and its electrical system:

• Heart Rate: It slows the electrical impulses that control the heart rate, which can help correct certain types of irregular heartbeats (arrhythmias).
• Pumping Force: It reduces the force with which the heart muscle contracts, decreasing the overall demand for oxygen.
• Oxygen Delivery: By dilating the coronary arteries, which are the vessels that supply the heart itself, it increases the amount of oxygen-rich blood reaching the heart muscle. This helps prevent chest pain, also known as angina.

Common Side Effects

Some people may experience mild side effects while taking verapamil. These often include:

• Constipation
• Dizziness or lightheadedness
• Headache
• Nausea
• Tiredness
• Flushing
• Swelling of the ankles or feet

Serious Side Effects

Seek medical attention right away if you notice any of the following serious symptoms:

• Slow, fast, or pounding heartbeat
• Fainting
• Shortness of breath or difficulty swallowing
• Sudden, unexplained weight gain
• Chest pain
• Signs of liver issues, such as yellowing of the skin or eyes, dark urine, or upper stomach pain
• Severe allergic reactions, including rash, hives, or swelling of the face and throat

Heart and Blood Pressure Concerns

Verapamil can slow the heart rate and lower blood pressure. It is generally not recommended for people with severe heart failure, cardiogenic shock, or very low blood pressure. It is also contraindicated for those with specific heart rhythm issues, such as sick sinus syndrome or advanced heart block, unless they have a functioning artificial pacemaker.

Liver and Kidney Impairment

The liver is primarily responsible for breaking down verapamil. In patients with liver disease, the drug may stay in the body longer, potentially increasing the risk of side effects. Dosage adjustments and careful monitoring are often necessary for those with liver or kidney impairment.

Drug Interactions

Verapamil interacts with several other medications. Notably, it can increase the risk of muscle damage when taken with simvastatin. The FDA recommends that the dose of simvastatin should not exceed 10 mg daily for patients also taking verapamil. It may also interact with other heart medications, such as beta-blockers or digitalis.

Neuromuscular Conditions

Verapamil may decrease neuromuscular transmission. It should be used with caution in patients with conditions like myasthenia gravis, as it may worsen muscle weakness.

Monitoring

Regular monitoring of heart rate and blood pressure is typically recommended during treatment to ensure the medication is working safely and to check for signs of excessively low heart rate or blood pressure.

Pregnancy

There are no adequate and well-controlled studies of verapamil use in pregnant women. Research indicates that verapamil crosses the placental barrier and can be detected in umbilical vein blood at the time of delivery. Because human data is limited, verapamil should only be used during pregnancy if a healthcare provider determines it is clearly necessary.

Patients who are pregnant or planning to become pregnant should discuss the potential risks and benefits with their doctor. A clinician can help determine if the benefits of managing a heart condition or high blood pressure outweigh the potential risks to the developing fetus.

Breastfeeding

Verapamil is excreted into human breast milk. Because of the potential for adverse reactions in nursing infants, healthcare providers often recommend that nursing be discontinued while verapamil is being administered. Alternatively, a doctor may suggest a different medication if breastfeeding is a priority. It is important to consult with a healthcare professional to weigh the risks and benefits of continuing breastfeeding while on this medication.

Oral Forms

Verapamil is primarily available as an oral medication in several different formats:

• Immediate-release tablets: These are designed to release the medication into the system shortly after being swallowed and are typically taken multiple times a day.
• Extended-release tablets: These are formulated to release the medication slowly over a longer period. They are often labeled as SR (sustained-release) or ER (extended-release).
• Extended-release capsules: Like the extended-release tablets, these capsules provide a gradual release of the medication into the bloodstream, often allowing for less frequent dosing.

Injectable Form

Verapamil is also available as a solution for intravenous (IV) injection. This form is used when a rapid response is needed and is administered by healthcare providers in a medical facility.

Combination Products

This medication is sometimes combined with other active ingredients, such as trandolapril, in a single extended-release tablet to help manage high blood pressure.

FDA Approval and Indications

Verapamil is approved by the U.S. Food and Drug Administration (FDA) for the management of several cardiovascular conditions. Its approved indications include:

• Hypertension (high blood pressure)
• Angina (chest pain)
• Certain heart rhythm disturbances, such as atrial fibrillation, atrial flutter, and paroxysmal supraventricular tachycardia

The medication is available in various formulations, including immediate-release tablets, extended-release tablets and capsules, and an intravenous injection for acute settings.

Safety Communications and Restrictions

The FDA has issued safety communications regarding drug interactions between verapamil and certain cholesterol-lowering medications (statins). Specifically, there are dose limitations for patients taking simvastatin (Zocor) concurrently with verapamil. Because verapamil can increase the levels of simvastatin in the blood, the FDA recommends that the dose of simvastatin not exceed 10 mg daily in these patients to reduce the risk of muscle injury, known as myopathy or rhabdomyolysis.

Regulatory Status

Verapamil is available as a generic drug. It does not currently have a boxed warning or a Risk Evaluation and Mitigation Strategy (REMS) program mandated by the FDA.

Verapamil may interfere with the way your body processes alcohol. This interaction can lead to higher-than-normal blood alcohol levels and cause the effects of alcohol to last longer than expected.

Consuming alcohol while taking this medication can also increase the risk of certain side effects, including:

• Dizziness
• Lightheadedness
• Fainting

Both alcohol and verapamil have the potential to lower blood pressure. When used together, they may cause an additive effect, leading to blood pressure that is too low. You should consult your doctor regarding the safety of consuming alcohol while using verapamil.