High Blood Pressure – Medication and Herb Interactions

High blood pressure is a hypertensive condition with numerous contributing factors. It usually has no symptoms, but it can cause serious problems. It is important to monitor it and control it through various modalities. This article looks at the prescribed medications for high blood pressure and any adversary interactions or contraindications with herbs, supplements and food.

Blood pressure is the force that your blood exerts on the walls of your arteries. When your heart beats blood is pumped into the arteries (Medline Plus, n.d.). This is when your blood pressure is the highest, and it is called systolic pressure. When your heart is at rest or between beats, your blood pressure falls and is at its lowest. This is called the diastolic pressure. When you receive a reading of your blood pressure reading normally get two numbers, the systolic and diastolic pressures. Usually they are written one above or before the other. A reading of 120/80 or lower is considered as normal blood pressure, a reading of 140/90 or higher is considered high blood pressure, a reading of 120 and 139 for the top number, or between 80 and 89 for the bottom number is considered as prehypertension.

High blood pressure is a hypertensive condition as a result of physiological, emotional, and mental factors, nervous anxiety and lower serum cholesterol. It usually has no symptoms, but it can cause serious conditions such as stroke, heart failure, heart attack and kidney failure. It is important to monitor it and control it through a healthy lifestyle habits and taking medicines and/or herbs, if needed with the necessary knowledge of any adversary interactions or contraindications.

High blood pressure can sometimes be controlled by one medicine, but often a combination of 2 or 3 medicines is required. Here are some of the types of medicines currently used by health care providers (AHA, n.d.).

Angiotensin-Converting Enzyme (ACE) Inhibitors are used for high blood pressure. ACE Inhibitors lower blood pressure by blocking the production of a hormone (angiotensin II) that narrows blood vessels, allowing the blood vessels to widen and blood to flow more easily.  An uncommon yet potentially serious adverse interaction of ACE inhibitors is an increased blood potassium level, and a harmless but persistent dry cough. ACE inhibitors are not suitable for pregnant women as they may damage the growing baby.

Angiotensin II receptor blockers work in a similar fashion as ACE inhibitors. They are used in heart failure and for preservation of kidney function. The adversary interactions with Angiotensin II blockers are that if taken with food, absorption of loatadine is decreases, therefore it should be taken one hour before food.

Calcium channel blockers, known as calcium antagonists, lower blood pressure by blocking the flow of calcium in the muscles of the heart and blood vessels, causing the blood vessels to relax and open up. They are often useful for older people and people with asthma or angina or peripheral vascular disease. Side effects vary among calcium channel blockers but can include flushing, swelling of the ankles, gastrointestinal upset (particularly with verapamil) and palpitations; however, generally these medicines are effective and well tolerated. Adversary interaction exists with pleurisy root as it contains cardiac glycosides.

Diuretics assist in lowering high blood pressure by helping the kidneys to pass accumulated salt and wáter and decrease the amount of fluid in the body. Diuretics also cause blood vessels to dilate (expand), which decreases the pressure on them. Some diuretics cause excess potassium to be excreted in the urine, which can cause problems in people with impaired kidney function. Other side effects of diuretics can include dizziness, weakness, excessive urination, a rare rash and gastrointestinal symptoms. People who have diabetes, liver disease or gout need to be closely monitored while taking diuretics as the medicines may aggravate these conditions. Adversary interactions exist with alder buckthorn, buckthorn as an increase loss of electrolytes occurs.

Adrenergic blockers (alpha-blockers and beta-blockers) assist in high blood pressure by reducing the number of nerve impulses that occur in the heart and blood vessels. Some alpha-blockers relax muscles in the walls of the blood vessels and reduce the resistance to blood flow thus allowing blood to flow more easily. Beta-blockers, work by blocking the action of adrenaline and noradrenaline in the heart. Adrenaline speeds up the heart and makes it pump harder, thus increasing blood pressure. Beta-blockers slow the heartbeat, and reduce the force of its contractions so less blood is pumped through the vessels. Beta Blockers increase potassium levels in the blood and can cause a dangerous condition called hyperkalemia (excess potassium). Adversary interaction exists with pleurisy root which contains cardia glycosides.

Beta-blockers are also used for angina, fast heartbeat and prevention of migraine. They are not suitable for people with asthma or certain heart conditions, and because they act on the nervous system they may cause lowered mood or lethargy in some people. They may sometimes cause narrowing of the airways, such as in asthma, and cold hands and feet. Unlike many other high blood pressure medicines, some beta-blockers are safe for use in pregnancy.

Centrally-acting antiadrenergic therapy lowers blood pressure by acting on the part of the brain that controls blood pressure, which expands blood vessels. Although very effective, they have more side effects than other antihypertensive medicines, including fatigue, dry mouth, depression, impotence and headache, so they are generally considered second- or third-line treatment. Methyldopa is still occasionally used to treat pregnant women who can’t take other blood pressure medicines because of the effect on the developing baby.

For high blood pressure the recommended herbs should possess hypnotic, hypotensive, nervine, sedative, antispasmodic characteristics. The following herbal formula contain herbs with the above characteristics, and cold infusion is used to prepare this mixture, as it is a quick and efficient method of preparing and administration and valerian root has volatile constituents and should not be heated (Tierra, 1998).

Garlic (Allium Sativum) has properties which lowers blood serum cholesterol levels. It has beneficial effects on heart disease due to allicin blocking the biosynthesis of cholesterol. Garlic lowers serum-triglycerides, beta lipoproteins, phospholipids and plasma fibrinogen levels. It helps to expand vessel walls due to methyl allyl trisulfide. Ajoene in garlic inhibits the tendency of blood cells to stick together (platelet aggregation), this reduces blood clotting. No adversary interaction exist with the prescribed medications for the high blood pressure condition.

Black Cohosh (Cimicifuga racemosa) possesses properties for the high blood pressure and it contains resinous constituents which inhibit the vasomotor centers in the central nervous system. Black Cohosh should be avoided during pregnancy. No adversary interaction exists with the prescribed medications for the high blood pressure condition.

Cayenne (Capsicum anyym) lowers blood cholesterol therefore decreasing blood pressure. It contains capsaicin which prevents rise in liver cholesterol and increases excretions of free cholesterol. It also prevents absorption of cholesterol. Cayenne should be avoided during pregnancy, and it has an adversary drug interaction with ACE Inhibitors.

Valerian root (Valeriana officinalis) has properties that affect the higher brain centers. It suppresses and regulates the autonomic nervous system and has no side effects even at high doses. No adversary interaction exist with the prescribed medications for the high blood pressure condition.

Kelp (Laminara, Macrocystis, Ascophyllum) has hypotensive activity which improves blood pressure and cardiac efficiency through laminine and histamine substances. It produces no side effects and no adversary interaction exist with the prescribed medications for the high blood pressure condition.

References

American Heart Association (AHA). (n.d.). Types of Blood Pressure Medications. Retrived December, 10, 2010 from http://www.heart.org/HEARTORG/Conditions/HighBloodPressure/PreventionTreatmentofHighBloodPressure/Types-of-Blood-Pressure-Medications_UCM_303247_Article.jsp

Brinker, F. (1998). Herb Contraindications and Drug Interactions. Sandy, OR: Ecletic Medical Publications.

Gaby, A.R. (2006). A-Z Guide to Drug-Herb-Vitamin Interations. New York, NY: Three River Press.

Medline Plus. (n.d.). High Blood Pressure. Retrived December, 10, 2010 from  http://www.nlm.nih.gov/medlineplus/highbloodpressure.html

Tierra, M. (1998).The Way of the Herbs. New York, NY: Pockets Books.