Medication, stress on the heart, and unstable angina

When you have an episode of unstable angina, your doctor may give you medicine to help reduce the stress on your heart and prevent damage to the heart muscle.

Advantages and disadvantages of some medicines for unstable angina

Medicine	What it does	Advantages	Disadvantages
Beta-blocker	Reduces workload of the heart by slowing heart rate and decreasing blood pressure	Easy to administer Decreases risk of a heart attack	Can lower blood pressure or heart rate too much Can make heart failure worse Can aggravate asthma
Calcium channel blocker	Reduces workload on the heart by lowering blood pressure, slowing heart rate, and increasing blood flow to the heart	Easy to administer Can reduce the number of angina attacks, especially when combined with beta-blockers and nitroglycerin	Can make heart failure worse if present Short-acting calcium channel blockers are not recommended.
Morphine	Relieves pain and anxiety Improves shortness of breath Lowers blood pressure	Helps decrease workload on the heart, which can improve blood flow Reduces anxiety Controls pain	Low blood pressure Nausea Slowed respiratory rate

Beta-blockers

Beta-blockers were developed to help treat people with chest pain. They can slow your heart rate and reduce your blood pressure, which decreases the workload on your heart. This in turn decreases the amount of oxygen that your heart muscle needs.

Beta-blockers should be considered for anyone having a heart attack. Initially they can be given through an intravenous (IV) tube, to make sure the medicine works immediately and to adjust the dose. Later they are given in pill form.

Beta-blockers can slow the heart rate and decrease blood pressure to low levels, can make heart failure worse, and can trigger asthma attacks in some people.

Calcium channel blockers

Calcium channel blockers are a group of medicines that share many of the beneficial effects of beta-blockers. In general, these medicines are not a first-line therapy for unstable angina. Calcium channel blockers may be used in some cases, such as when beta-blockers cannot be taken.

Calcium channel blockers can be harmful to people who have moderate to severe heart failure because these drugs may decrease the heart's ability to pump forcefully (contractility). Some calcium channel blockers, such as verapamil and diltiazem, can disrupt the normal electrical system of the heart.

Morphine

Morphine helps relieve the pain and anxiety that typically comes with an episode of unstable angina. As soon as you are more comfortable, it is easier to control your heart rate and blood pressure and thereby reduce the work your heart must do. This in turn decreases the amount of oxygen that your heart needs, which also helps relieve your chest pain.

Doctors commonly give morphine to people whose chest pain does not go away after taking several nitroglycerin tablets. Morphine provides pain relief within a few minutes.

Morphine is highly effective, but it can also cause a decrease in blood pressure and severe nausea or slow the respiratory rate.