Medications used in HCM
Drug treatment or medication is primarily given when a person has some or all of the symptoms described earlier. Increasing, decreasing or discontinuing medication should only be done with consultation with your cardiologist and/or your HCM specialist. The choice of treatment will vary from individual to individual but the common groups of drugs used are as follows:
Beta-Blocking drugs slow the heart beat and reduce its force of contraction. These drugs usually relieve chest pain, breathlessness and palpitation. Beta blockers have such names as atenolol, metoprolol, nadolol, propranolol, sotalol and others (names normally end in “ol”). Beta-blockers are also widely used in medical practice for other types of heart disease and for high blood pressure. Occasionally excessive heart rate slowing with these drugs can cause fatigue.
The second major group of drugs used are the calcium antagonists or calcium channel blockers. Within this group verapamil is the drug which has been most commonly used in HCM. It improves the filling of the heart and like beta-blockers, reduces symptoms such as chest pain, breathlessness and palpitations. Also, like beta-blockers, verapamil can cause excessive slowing of the heart rate and lower blood pressure. Other calcium channel blockers include Nifedpine and Diltiazem.
These drugs might be used when an arrhythmia such as tachycardia is detected and felt to be important in an individual case. Sotolol (BetaPace) is a very helpful medication for those who encounter arrhythmias. It may lower blood pressure and appears to have few side effects. Of these anti-arrhythmic drugs, Amiodarone (Cordarone) is the most commonly used in Hypertrophic Cardiomyopathy. It is a powerful and effective drug. But it does have several potentially serious side effects, including pulmonary toxicity (2%-7% in some studies, but as high as 10%-17% in some reports) liver function test abnormalities (4%-9%), hyperthyroidism (about 2%), and hypothyroidism (2%-4% in some cases, but as high as 8%-19% in some series), proarrhythmia (2%-5%) and optic neuropathy, which can lead to blindness. Some minor side effects include sensitivity to sunlight, which can be avoided with use of barrier creams which block visible and ultraviolet light. It is very important for those on amiodarone to follow up with strict monitoring of lung, liver and thyroid functions. These tests should be performed every 3-6 months (see your doctor to schedule these tests). Although this drug has many serious side effects it is a very useful drug when monitored and taken in the proper dose; those with HCM should take low doses of amiodarone, about 200mg per day as higher doses can be deadly.
Another anti-arrhythmic drug which has been used is Disopyramide, however in HCM it is not used for these properties but for its ability to help relieve obstruction. It may improve symptoms independently of its anti- arrhythmic effects, possibly by reducing the force of contraction of the heart. Disopyramide (Norpace) has also been used in Europe and Canada for a longer period than in the USA for this purpose but it’s use in the USA is growning.
There are a number of specific complications described earlier which are rare but which require the use of additional drugs.
Patients with episodic or persistent atrial fibrillation should take anticoagulants (blood thinners) to prevent clot formation in the atria. Warfarin (Coumadin) is the tablet commonly used with a long history of success in HCM. It requires monitoring with a blood test, approximately on a monthly basis. Newer drugs have entered the consumer market including Perdaxa (dabigatran etexilate) and Xarelto (Rivaroxaban). (There are no trials in HCM with these new agents and choice of anticoagulant therapy should be discussed with your HCM specialist until more in known about these agents.)
Occasionally patients develop fluid retention and in these situation diuretics “water pills” which increase urine flow are administered. The most commonly prescribed diuretic is Furosemide (Lasix). If your weight raises by 2 or more pounds then it is most likely advisable to continue to take the diuretic, however if you do not see the weight gain discuss this with your doctor, you may not need to take diuretics each day (an every other day schedule may be advised). If you have been prescribed diuretics by your doctor it is advised to weigh yourself each day at the same time (first thing in the morning is advised). It is also imperative to maintain an appropriate blood potassium level when taking diuretics.
Although endocarditis is rare, persons who have out flow obstruction and turbulent blood flow should receive antibiotic prophylaxis prior to dental procedures (including cleanings) and any other situations where there is an increased risk of bacteria entering the bloodstream.
Summary of Drug Treatment
In summary, a variety of drug treatments are currently used in Hypertrophic Cardiomyopathy (HCM) and of course new drugs may be discovered in the future. The need for any treatment and choice of that treatment has to be made on an individual basis and may change in any one individual over the years. It is very important to discuss your symptoms with your doctor and plan a treatment plan for you, as each patient with Hypertrophic Cardiomyopathy (HCM) is different. Medication should NEVER be stopped without first consulting with your doctor, specifically your cardiologist. While medications can be stopped some drugs can have a serious complication if stopped abruptly, please work with your doctor to manage all medications.
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