Newport Beach Neurologists

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Of all the preventative medicines available across the United States, the drugs known as beta blockers are probably the most frequently prescribed. The "beta" refers to receptors on the blood vessels known as beta receptors. Beta blockers prevent the chemical interaction of certain chemicals with this receptor, hence, the term "beta blockers." Of this family of drugs, the most frequently used drug is Inderal, although others, such as Tenormin and Corgard, will also be used occasionally. Beta blockers were developed primarily for control of cardiac symptoms, but it was found coincidentally that these drugs had a remarkable effect on migraine prevention.

After this chance observation was made, studies conducted in the late 1960s and early 1970s confirmed the improvement in migraine with treatment. The studies show that sixty to seventy percent of all migraine subjects experienced a decrease of more than fifty percent in the incidence and severity of their headaches when treated with one of these beta blockers. Two beta blockers are currently FDA approved for use in the preventative treatment of migraine: propranolol (Inderal and Inderal LA) and timolol (Blocadren). Three other beta blockers are also used, although these drugs are not approved by the FDA for indication in migraine. These three agents are: atenolol (Tenormin), metoprolol (Lopressor), and nadalol (Corgard).

MECHANISM OF ACTION

The possible mechanisms of action of propranolol in the prophylactic treatment of migraine are listed below:

  1. Blockade of these beta adrenergic receptors results in inhibition of arterial dilatation.

  2. The drug may block the sticky elements of the blood, the platelets, from adhering together and thus releasing substances which cause blood vessels to constrict and dilate.

  3. There may be a central mechanism of action in the brain "turning off" the generators that cause migraine.

DOSAGE

Inderal is prescribed in milligram dosages of 60, 80, 120, 160, and occasionally even up to 240 mg. per day. Usually, the patient will be started on a low dosage of the drug to test the patient's response. Unfortunately, many physicians will abort treatment long before they have given the drug a chance to work. Inderal may take six to twelve weeks to be effective. Not only that, but the dosage may have to be increased as the weeks go by. One of the major reasons people are failures on preventative or prophylactic drugs is that they have not taken the medication long enough, nor have they taken it in a sufficient dosage.

SIDE EFFECTS

As with every medication, Inderal has its side effects. However, some side effects are very unique to the beta blockers. Occasionally on starting the drug, a feeling of lethargy may be experiences. After all, the role of beta blockers is to prevent the effects of "adrenaline" on the body. Sometimes there may be some overshoot effect, and the patient may feel a little tired and lethargic.

Occasionally, some may experience depression on the drug. Rarely does it ever get so severe as to necessitate stopping the medicine, but this has been reported on occasion. Another side effect which men find distressing is the appearance of impotence. Even on rare occasions, orgasmic dysfunction has been noted in women; however, fortunately these side effects are relatively rare.

If the side effects are experienced, cessation of the drug usually abolishes them. A word of caution! When stopping Inderal, it should never be discontinued immediately or sometimes there may be rebound migraine or even rebound tachycardia (speeding up of the heart rate). Inderal should be tapered over a period of weeks. Because most physicians now use the long-acting variety of Inderal, it is necessary to switch over to the short-acting medication so that the drug can be tapered when that is appropriate.

CONTRAINDICATION

Not every patient is a candidate for Inderal. Diabetes is a contraindication because Inderal can sometimes mask the effects of hypoglycemia which is unacceptable in a diabetic patient. Similarly, patients with bronchial asthma or severe sinusitis should not be treated with this drug. Elderly patients with poor cardiac function should avoid beta blockers in general because the drug may sometimes precipitate congestive heart failure.

DRUG INTERACTIONS

Many drug interactions and related problems have been reported with beta blockers. The following is a summary of some areas of special concern:

  1. Calcium channel blocking agents and other hypotensive agents - When beta blockers are combined with Verapamil or other medicines used in the treatment of hypertension, the combined effects of the drugs may be increased. The blood pressure in these cases may drop too low (hypotension). Patients should be monitored closely, especially during initiation of treatment. The same procedure should be followed when beta blockers are used with any other hypotensive agents. Excessive slowing of the heart may occur when beta blockers are administered with other agents that decrease heart rate.

  2. Histamine antagonists - A commonly used stomach medicine, cimetidine (Tagamet), has been shown to increase the effect of beta blockers by inhibiting their breakdown in the liver. Doses of the beta blocker must be reduced in patients using this medication.

CONCLUSION

Due to their established efficacy and safety record, beta blockers play a role in the prophylaxis of migraine with and without aura. These agents have been demonstrated to reduce the frequency and intensity of migraine attacks. If patients are screened for contraindications to these medicines, then fewer side effects are reported.

Mission Statement

Newport Beach Neurologists specializes in the treatment of pain, severe chronic headache, and multiple sclerosis.

Our guiding philosophy is that pain can stem from the body, the mind, or both. Thus, we are structured as an integrative entity equipped with all resources-medical, psychiatric, and psychological-to help patients manage pain and multiple sclerosis.