How blood pressure medicine works, Part III
Note: This is another in a series of articles on blood pressure and medications used to control high blood pressure.
This month we’ll discuss beta-blockers and calcium channel blockers—two types of medications used to control elevated blood pressure.
The heart acts as a pump, propelling the blood through the arteries and veins (the “pipes”). One way to lower blood pressure is to lower the number of contractions or beats the heart makes in one minute. The faster rate produces a higher volume of blood being pumped through the system, which results in higher blood pressure. Beta-blockers lower the heart rate by blocking the action of adrenaline (norepinephrine/epinephrine) on the nerve endings in the heart. Normally, these substances would stimulate these nerve endings and result in the heart beating faster. When this effect is blocked (which is what the beta-blockers do), the heart rate is maintained at a slower rate and blood pressure is subsequently lowered.
Beta-blocker medications can be a good choice for professional drivers, but they should be tailored to the needs of the specific individual. As with every medication, there are side effects and contraindications (medical conditions that are not compatible with the medications and could cause problems). Some of the unintended benefits of beta-blockers include: less anxiety, clear thinking, fewer headaches, and, in general, a calming effect on the individual. Some unpleasant side effects include: increased sleepiness, depressed mood, slowed heart rate that can result in dizziness or blackout spells, poor sex drive and/or difficulty maintaining an erection.
In most cases, individuals with the following conditions should avoid taking beta-blocker medications: depression, heart failure, asthma, emphysema, severe insulin dependent diabetes with frequent episodes of hypoglycemia or blackouts, and some lipid/cholesterol disorders.
Calcium channel blockers (CCBs) are my least favorite class of drugs for over-the-road drivers because they can cause swelling of the legs and constipation. These are unpleasant side effects for someone whose legs are hanging down for 10 to 14 hours a day and who is prone to constipation due to limited access to bathroom facilities on the road. Drivers also restrict their fluid intake to prevent frequent stops, and the dietary habits of many truckers increase the risk of constipation. Make sure that your physician knows what profession you are in when he or she is prescribing your medications.
Next month, we’ll wrap up talking about the “pump and pipes.” In the meantime, you Kings of the Highways and Queens of the Interstate stay safe and stay healthy.
Dr. John McElligott is the founder of Professional Drivers Medical Depots (pd-md.com), a planned nationwide network of medical clinics located at truck stops and travel centers.