Thursday, January 24, 2013

Antihypertensive Medications

Hypertension is defined as an elevated blood pressure above the acceptable range. Currently, a reading of 120 – 139 mmhg (millimiters of mercury) for systolic and 80-89 mmhg for diastolic means that the person is in the prehypertension stage, a reading of 140 – 159 mmhg for systolic and 90-99 mmhg for diastolic means stage 1 of hypertension, a reading of 160 mmhg for systolic and 100 mmhg for diastolic means stage 2 of hypertension and a reading of 180 mmhg for systolic and 110 mmhg for diastolic means that the individual is in hypertensive crisis.

The treatment of hypertension  is done in different ways. One of the method is using an antihypertensive medication. Prescribing a drug called diuretic is one of the option among others. Diuretics are drugs that promote the process of diuresis [an increase in water retention] resulting in an increase in urination. The classifications of diuretics are thiazides, potassium sparing, carbonic anhydrase inhibitors, xanthines and loop diuretics.

Commonly prescribed thiazide diuretics are bendroflumethiazide and hydrochlorothiazide. These drugs inhibit the reabsorption of sodium at the distal convoluted tubules of the kidneys. The common adverse effects are muscle cramps and weakness, thirst, hypotension, confusion, fatigue, hypokalemia (low levels of potassium) and gastrointestinal disturbances such as nausea and vomiting. The potassium sparing diuretics that are commonly prescribed are spironolactone, triamterene and amiloride. These drugs function to inhibit the exchange between sodium and potassium in the collecting ducts of the kidneys. The adverse effects are hyperkalemia (elevated levels of potassium) resulting in arrhythmia and muscle weakness, and metabolic acidosis that results in seizures, coma, lethargy and breathing difficulties.

The carbonic anhydrase inhibitors diuretics that are commonly prescribed are azetazolamide and dorzolamide. These drugs function to inhibit the secretion of hydrogen ions in the proximal tubules of the kidneys. The common adverse effects are hypokalemia and central nervous system disturbances such as seizures and coma. The commonly prescribed xanthine diuretics are theophylline, theobromine and caffeine. These drugs function to inhibit reabsorption of sodium and increase the glomerular filtration rate of the kidneys. Theophylline is not generally recommended because of the toxic effects to the cardiovascular system.

Over all, the general adverse effects of diuretics are imbalances in the potassium levels in the blood, hypercalcemia (elevated levels of calcium), hyponatremia (lower levels of sodium), hyperuricemia (excessive uric acid in the blood) and orthostatic hypotension (postural hypotension). Diuretics are contraindicated for people with gout because it will elevate the uric acid in the blood.

A health teaching regarding the adverse effects of diuretics should be done by the healthcare provider. Monitoring other bodily reactions such as weight changes and neurological deficits is needed due to concern over potential negative effects of the drug to the body. Constant updates to the healthcare providers regarding bodily changes are important so that necessary adjustment in the dosage can be promptly done.

You can read more about hypertension in my books : Blood Pressure Management : Hypertension and Hypotension  A Guide for Patients, Nurses and other HealthcareProfessionals ( Available at; link : ). Managing Blood Pressure Effectively  A Guide for Well Informed Patients, Nurses and Other Healthcare Professionals ( Available at; link : ). Both books are downloadable as ebooks.

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See you next time.

Solomon Barroa  R.N.
Home Health Nurse and Medical Author

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