Hypertension Blog

Diuretics promote renal excretion of water and electrolytes by increasing the glomerular filtration rate. They can also decrease sodium reabsorption and increase the rate of sodium excretion .

Diuretics are divided into several classes: loop, potassium sparing, thiazide, and thiazide-like. Each of these classes has a single mechanism of action. Combination diuretics contain two different classes of diuretic .

Potassium Sparing Diuretics

Potassium sparing diuretics have weaker diuretic and antihypertensive effects than loop diuretics. However, by acting on the distal tubule to inhibit the reabsorption of sodium and water, these drugs increase potassium retention. The potassium sparing diuretics include amiloride, spironolactone, and triamterene.

Indications and Contraindications

Physicians prescribe potassium sparing diuretics to treat patients with hypertension or with edema from heart failure. These drugs are also used in combination with other classes of diuretics to maintain a patient’s serum potassium levels.

Potassium sparing diuretics shouldn’t be used to treat patients with anuria, hyperkalemia, or impaired renal function. Amiloride should be used cautiously in those with dehydration, diabetes, or acidosis. And spironolactone should be given cautiously to patients with hepatic disease. Use triamterene cautiously in patients with heart failure, renal disease, and cirrhosis. When administering any potassium sparing diuretics, monitor your patient’s serum chemistry levels for early indications of electrolyte imbalance and increasing renal or hepatic failure.

Diuretics Side Effects

These drugs produce fewer side effects than other diuretics. However, a patient taking a potassium sparing diuretic has a greater risk of hyperkalemia, especially if he’s also taking potassium supplements.

Dose-related adverse effects include megaloblastic anemia, arrhythmias, headache, dizziness, and orthostatic hypotension. Spironolactone may cause amenorrhea, a deeper voice, gynecomastia, hirsutism, irregular menses, and postmenopausal bleeding. Triamterene may cause a bluish discoloration of the urine.

Your patient may experience hyperkalemia if he takes one of these drugs with another potassium sparing diuretic, an ACE inhibitor, or a salt substitute. If given with lithium, a potassium sparing diuretic may provoke lithium toxicity. Nephrotoxicity may increase if a patient takes triamterene with indomethacin. Also, aspirin decreases the effects of spironolactone.

The effects of cerebrovascular disease on your patient and his family can be devastating. A tremendous amount of education and support is needed for optimum recovery.

During the acute phase of a CVA, orient the patient and his family to the unit, to the procedures being performed and the equipment used, and to the treatment plan. Explain the need for rehabilitative therapy after the acute phase has passed.

Once the patient’s condition has stabilized and the amount of cerebral tissue damage has been determined, explain the disease, his deficits, and the planned rehabilitation. If necessary, ensure that each rehabilitation team member explains his or her specialty so that the patient and his family fully understand the rehabilitation process.

Teach the patient the signs and symptoms of a CVA and stress the importance of seeking treatment immediately if any of the following occur:

• sudden onset of weakness, numbness, or paralysis of the face, arm, or leg, usually on one side of the body
• sudden blurring or loss of vision in one or both eyes
• loss of speech or trouble talking or understanding speech
• sudden severe headache
• unexplained dizziness or loss of balance, especially if combined with other signs and symptoms.

If the physician prescribes an antihypertensive, anticoagulation, or anti platelet aggregation drug, teach your patient the name of the drug, its dosage, and its therapeutic and adverse effects. If he must take an anticoagulant, also teach him the signs and symptoms of bleeding that he should report .

If the physician has prescribed warfarin, tell your patient which drugs interact with it. Instruct him to maintain a diet that provides moderate amounts of vitamin K. Explain that extreme variations in vitamin K intake can cause wide fluctuations in the anticoagulant level. Tell the patient to avoid trauma and to wear a medical alert tag or bracelet at all times. Inform him that he’ll need frequent blood tests for his physician to adjust the warfarin dose.

Depending on the amount of cerebral damage, your patient may be transferred to a rehabilitation facility or a skilled nursing facility for further treatment. If he requires a wheelchair or walker, tell him that a home care nurse or other health provider should visit his home to identify physical barriers that would limit their use.

Explain that the home care nurse will monitor his vital signs, check his compliance with antihypertensive drug therapy, and assess his response to the drug. She’ll evaluate his bowel and bladder function and provide retraining, if necessary. She’ll also assess his response to rehabilitation, determining which assistive devices might be useful to him.

Monitor your patient’s neurologic status frequently. Look for signs and symptoms of worsening neurologic deficits, such as mental status changes, agitation, weakness, unequal pupils, vomiting, and bradycardia. Each time, compare your findings with those of your previous assessment and immediately report any changes to the physician.

If you’re administering mannitol, closely monitor your patient’s intake and output to assess fluid balance and fluid loss. Include the mannitol as part of his intake.

Monitor his cardiovascular status by taking continuous blood pressure readings using an arterial line or an automatic sphygmomanometer. Be alert for potential cardiac decompensation, such as ectopy or heart block.

Assess the rhythm and depth of the patient’s respirations, his respiratory rate, and any changes in his breathing pattern. Cheyne-Stokes respirations-episodes of apnea that last 10 to 60 seconds followed by a gradual increase in respiratory rate and depthmay result from brain stem herniation.

Closely monitor your patient’s serum electrolyte levels, including his potassium, sodium, and chloride levels. Also, check his BUN, creatinine, and arterial blood gas (ABG) levels and blood pH. Obtain a complete blood count, as well.

Treatment Plan

During the acute phase of your patient’s condition, orient him and his family to the unit. Explain the treatment plan, including the diagnostic tests that will be performed.

Before discharge, explain the need for strict compliance with the prescribed antihypertensive drug regimen. Stress the importance of reducing risk factors that can exacerbate his hypertension. Be sure to describe the underlying disorder that led to his severely high blood pressure and subsequent hypertensive encephalopathy.

If your patient will be discharged to his home, the home care nurse should evaluate his compliance with the drug regimen and recommended lifestyle changes. She should monitor his blood pressure and be alert for the recurrence of neurologic deficits, such as localized weakness, agitation, confusion, blurred vision, dizziness, and light­headedness.

A patient who has had hypertensive encephalopathy may need extensive rehabilitation. His home care nurse should oversee the rehabilitative therapies he’ll need, such as exercise and physical therapy. And she should reevaluate his plan of care regularly to determine whether it remains realistic and whether the goals are being met.