Drugs Affecting Blood Pressure

Blood Pressure Control

Blood pressure (BP) is determined by several factors:

• Heart Rate: The number of times the heart beats per minute.
• Stroke Volume: The amount of blood pumped out of the ventricle with each heartbeat.
• Total Peripheral Resistance: The resistance of the muscular arteries to the blood being pumped through them.
• Baroreceptors: These detect changes in blood pressure and signal the body to make adjustments.
• Renin-Angiotensin-Aldosterone System (RAAS): A hormonal system that regulates blood pressure and fluid balance.

Renin-Angiotensin-Aldosterone System (RAAS)

The RAAS system is crucial in controlling blood pressure. Here's how it works:

1. Renin Release: Juxtaglomerular cells in the kidneys release renin in response to decreased perfusion pressure.
2. Angiotensinogen Production: The liver produces angiotensinogen.
3. Angiotensin I Formation: Renin reacts with angiotensinogen to form angiotensin I.
4. Angiotensin II Formation: Angiotensin I is converted to angiotensin II in the pulmonary capillary bed by a converting enzyme.
5. Angiotensin II Actions:
   • Powerful vasoconstrictor.
   • Stimulates the release of aldosterone from the adrenal cortex.
6. Aldosterone Action: Aldosterone increases sodium and water reabsorption by the kidney tubules, leading to increased blood volume.
7. ADH Release: Angiotensin II also stimulates ADH (antidiuretic hormone) release, leading to water retention and increased blood volume.

Risks of Hypertension

Hypertension can lead to several risks for coronary artery disease (CAD), including:

• Thickening of the heart muscle.
• Increased pressure generated by the muscle during contraction.
• Increased workload on the heart.

Conditions Related to Untreated Hypertension

Untreated hypertension can result in:

• CAD and cardiac death
• Stroke
• Renal failure
• Loss of vision

Categories of Hypertension

The severity of hypertension is categorized as follows:

• Normal: Systolic BP (SBP) < 120 mm Hg and Diastolic BP (DBP) < 80 mm Hg
• Elevated: SBP 120-129 mm Hg and DBP < 80 mm Hg
• Hypertension Stage 1: SBP 130-139 mm Hg or DBP 80-89 mm Hg
• Hypertension Stage 2: SBP \geq 140 mm Hg or DBP \geq 90 mm Hg

Factors Increasing Blood Pressure

Several factors can increase blood pressure:

• High levels of psychological stress
• Exposure to high-frequency noise
• High-salt diet
• Lack of rest
• Genetic predisposition

Use of Drugs Affecting Blood Pressure Across the Lifespan

Children

Determining normal BP levels in children is relatively new. Hypertension can start in childhood, and screenings are being done to establish normal values for each age group. Children are more likely to have secondary hypertension due to renal disease or congenital problems like coarctation of the aorta.

• Treatment: Should be cautious due to unknown long-term effects of antihypertensive agents. Lifestyle changes (weight loss, increased activity) should be tried first. If drug therapy is needed, a mild diuretic may be used, with regular monitoring of blood glucose and electrolytes. Beta-blockers have been used with success. Calcium-channel blockers may be a first consideration if drug therapy is needed. ACE inhibitors and ARBs have not been established as safe and effective in children.
• Monitoring: Careful follow-up is essential to monitor for changes in BP and adverse effects.

Adults

• Education: Adults should be instructed about adverse reactions that should be reported immediately. Reminded of safety precautions in hot weather or with fluid depletion (e.g., diarrhea, vomiting). The interacting effects of various drugs should be evaluated if they are taking other medications.
• Lifestyle: Importance of weight loss, smoking cessation, and increased activity should be emphasized.
• Pregnancy: Safety of these drugs during pregnancy has not been established. ACE inhibitors, ARBs, and renin inhibitors should not be used during pregnancy; women of childbearing age should use barrier contraceptives. Calcium-channel blockers and vasodilators should only be used if the benefit to the mother outweighs the potential risk to the fetus. Labetalol, a beta-blocker, is often used first with treating HTN during pregnancy.
• Lactation: Drugs enter breast milk and can cause serious adverse effects in the baby. Caution should be used or another method of feeding the baby should be used if one of these drugs is needed during lactation.

Older Adults

• Susceptibility: Older adults are more susceptible to toxic effects and are more likely to have underlying conditions that could interfere with drug metabolism and excretion. Renal or hepatic impairment can lead to drug accumulation. The dose should be reduced and the patient monitored closely if dysfunction is present.
• Drug Regimen: The total drug regimen should be coordinated with careful attention to interactions among drugs and alternative therapies.
• Falls: Older adults need to use special caution in any situation that could lead to a fall in BP, such as loss of fluids, lack of fluid intake, or excessive heat. Dizziness, falls, or syncope can occur if the BP falls too far. BP should always be taken immediately before administering an antihypertensive in an institutional setting to avoid excessive lowering of BP.
• Sustained-Release: Older patients should be cautioned about sustained-release antihypertensives that cannot be cut, crushed, or chewed to avoid the potential for excessive dosing if these drugs are inappropriately cut.

Hypotension

Hypotension occurs when BP becomes too low. This can happen when:

• The heart muscle is damaged and unable to pump effectively.
• There is severe blood or fluid loss, causing volume to drop dramatically.
• There is extreme stress, depleting the body’s levels of norepinephrine, leaving the body unable to respond to stimuli to raise BP.

Antihypertensive Agents

Classes of antihypertensive agents include:

• ACE Inhibitors
• Angiotensin II Receptor Blockers
• Renin Inhibitors
• Calcium Channel Blockers
• Vasodilators
• Diuretics
• Sympathetic Nervous System Blockers

Stepped Care Management of Hypertension

1. Step 1: Lifestyle modifications are instituted (weight reduction, smoking cessation, moderation of alcohol intake, reduction of dietary salt, increase in aerobic physical activity).
2. Step 2: If there is inadequate response, drug therapy is added.
3. Step 3: If there is still inadequate response, consider a change in drug dose or class, or addition of another drug for combined effect.
4. Step 4: If there is still inadequate response, a second or third agent or diuretic is added if not already prescribed.

ACE Inhibitors

ACE (Angiotensin-Converting Enzyme) inhibitors:

• Benazepril (Lotensin)
• Captopril (Capoten)
• Enalapril (Vasotec)
• Enalaprilat (generic)
• Fosinopril (generic)
• Lisinopril (Prinivil, Zestril)
• Moexipril (Univasc)
• Perindopril (Aceon)
• Quinapril (Accupril)
• Ramipril (Altace)
• Trandolapril (Mavik)

Expected Pharmacological Action

ACE inhibitors reduce the production of angiotensin II by blocking the conversion of angiotensin I to angiotensin II and increasing levels of bradykinin, leading to:

• Vasodilation (mostly arteriole)
• Excretion of sodium and water, and retention of potassium by actions in the kidneys
• Reduction in pathological changes in the blood vessels and heart that result from the presence of angiotensin II and aldosterone

Therapeutic Uses

• Hypertension
• Heart failure
• Myocardial infarction (to decrease mortality and to decrease risk of heart failure and left ventricular dysfunction)
• Diabetic and nondiabetic nephropathy
• For clients at high risk for a cardiovascular event, Ramipril is used to prevent MI, stroke, or death.

Contraindications

• Allergies
• Impaired renal function
• Pregnancy and lactation
• Caution in CHF

Complications

• First-Dose Orthostatic Hypotension
  • Nursing Actions:
    • If the client is already taking a diuretic, stop the medication temporarily for 2 to 3 days prior to the start of an ACE inhibitor.
    • Taking another type of antihypertensive medication increases the hypotensive effects of an ACE inhibitor.
    • Start treatment with a low dosage of the medication.
    • Monitor blood pressure for 2 hr after initiation of treatment.
  • Client Education: Change positions slowly and lie down if feeling dizzy, lightheaded, or faint.
• Cough
  • Related to inhibition of kinase II (alternative name for ACE), which results in increase in bradykinin
  • Client Education: Inform clients of the possibility of experiencing a dry cough and to notify the provider. Discontinue the medication.
• Hyperkalemia
  • Nursing Actions:
    • Monitor potassium levels to maintain a level within the expected reference range of 3.5 to 5 mEq/L.
    • Advise clients to avoid the use of salt substitutes containing potassium.
    • Monitor for manifestations of hyperkalemia (numbness and tingling) and paresthesia in hands and feet.
• Rash and Dysgeusia (altered taste)
  • Primarily with captopril
  • Client Education:
    • Inform the provider if these effects occur.
    • Adverse effects will stop with discontinuation of the medication.
• Angioedema
  • Swelling of the tongue and oral pharynx
  • Nursing Actions:
    • Treat severe effects with subcutaneous injection of epinephrine.
    • Discontinue medication.
• Neutropenia
  • Rare but serious complication of captopril
  • Nursing Actions:
    • Monitor WBC counts every 2 weeks for 3 months, then periodically.
    • This condition is reversible when detected early.
    • Inform clients to notify the provider at the first indications of infection (fever, sore throat). Discontinue medication.

Contraindications/Precautions

• Pregnancy Risk: During the second and third trimester, related to fetal injury. Discontinue as early in pregnancy as possible.
• Contraindicated in clients who have a history of allergy to or angioedema from ACE inhibitors, in bilateral renal artery stenosis, or in clients who have a single kidney.
• Use cautiously in clients who have kidney impairment and collagen vascular disease because they are at greater risk for developing neutropenia. Closely monitor these clients for manifestations of infection.

Interactions

• Diuretics can contribute to first-dose hypotension.
  • Client Education: Temporarily stop taking diuretics 2 to 3 days before the start of therapy with an ACE inhibitor.
• Antihypertensive medications can have an additive hypotensive effect.
  • Client Education: Dosage of medication might need to be adjusted if ACE inhibitors are added to the treatment regimen.
• Potassium supplements and potassium-sparing diuretics increase the risk of hyperkalemia.
  • Client Education: Only take potassium supplements if prescribed. Avoid salt substitutes that contain potassium.
• ACE inhibitors can increase levels of lithium.
  • Nursing Actions: Monitor lithium levels to avoid toxicity.
• Use of NSAIDs can decrease the antihypertensive effect of ACE inhibitors.
  • Nursing Actions: Avoid concurrent use.

Nursing Administration

• Administer ACE inhibitors orally except enalaprilat, which is the only ACE inhibitor for IV use.
• Client Education:
  • The medication is prescribed as a single formulation or in combination with hydrochlorothiazide (a thiazide diuretic).
  • Blood pressure is monitored after the first dose for at least 2 hr to detect hypotension.
  • Take captopril and moexipril at least 1 hr before meals. Other ACE inhibitors are taken with or without food.
  • Notify the provider if cough, rash, dysgeusia (altered taste), or indications of infection occur.
  • Rise slowly from sitting.
  • Avoid activities that require alertness until effects are known.
  • Report if pregnancy is suspected.

Prototype ACE Inhibitor: Captopril

• Indications: Treatment of hypertension, heart failure, diabetic nephropathy, and left ventricular dysfunction after an MI.
• Actions: Blocks ACE from converting angiotensin I to angiotensin II, leading to a decrease in BP, a decrease in aldosterone production, and a small increase in serum potassium levels along with sodium and fluid loss.
• Pharmacokinetics:
  • Route: Oral
  • Onset: 15 min
  • Peak: 30-90 min
  • T1/2: 2 hours; excreted in the urine.
• Adverse Effects: Tachycardia, MI, rash, pruritus, gastric irritation, aphthous ulcers, peptic ulcers, dysgeusia, proteinuria, bone marrow suppression, cough.

Angiotensin II Receptor Blockers (ARBs)

• Prototype: Losartan
• Other Medications: Irbesartan, Candesartan, Olmesartan, Telmisartan

Expected Pharmacological Action

These medications block the action of angiotensin II in the body. This results in:

• Vasodilation (arterioles and veins)
• Excretion of sodium and water (by decreasing release of aldosterone)

Therapeutic Uses

• Hypertension
• Heart failure (valsartan and candesartan)
• Stroke prevention (losartan)
• Delay progression of diabetic nephropathy (irbesartan and losartan)
• Protect against MI, stroke, and death from cardiac causes in individuals unable to tolerate ACE inhibitors (telmisartan)
• Reduce mortality following an acute myocardial infarction (valsartan)
• Slow the development of diabetic retinopathy (losartan)

Complications

The major difference between angiotensin II receptor blockers (ARBs) and ACE inhibitors is that ARBs block the actions of angiotensin II and ACE inhibitors block the formation of angiotensin II.

• Angioedema
  • Nursing Actions: Treat severe effects with subcutaneous injection of epinephrine. Discontinue medication.
  • Client Education: Observe for manifestations (skin wheals, swelling of tongue and pharynx) and notify the provider immediately.
• Fetal Injury
  • Client Education: If a client is of childbearing age, use contraception while on this medication.
• Hypotension
  • Nursing Actions: Monitor blood pressure. Advise clients to rise slowly from a sitting position.
• Dizziness, Lightheadedness
  • Client Education: Avoid activities that require alertness until effects are known.

Contraindications/Precautions

• Pregnancy Risk Category D. ARBs cause fetal damage in the second and third trimesters. Discontinue as early in pregnancy as possible.
• These medications are contraindicated in clients who have bilateral renal stenosis or in a single remaining kidney because of the risk for kidney injury.
• Use cautiously in clients who experienced angioedema with an ACE inhibitor.

Interactions

• Antihypertensive medications can have an additive effect when used with ARBs.
  • Nursing Actions: Adjust dosage of medication if ARBs are added to the treatment regimen.
• Increased risk for lithium toxicity
  • Nursing Actions: Monitor lithium levels and adjust dosage

Nursing Administration

• Administer medications by oral route.
• Take ARBs with or without food.
• Client Education:
  • Medication is prescribed as a single formulation or in combination with hydrochlorothiazide.
  • If taken for heart failure, monitor weight and edema.

Prototype ARB: Losartan

• Indications: Alone or as part of combination therapy for the treatment of hypertension; treatment of diabetic nephropathy with an elevated serum creatinine and proteinuria in patients with type 2 diabetes and hypertension.
• Actions: Selectively blocks the binding of angiotensin II to specific tissue receptors found in the vascular smooth muscle and adrenal glands; blocks the vasoconstriction and release of aldosterone associated with the RAAS.
• Pharmacokinetics:
  • Route: Oral
  • Onset: Varies
  • Peak: 1-3 h
  • Duration: 24 h
  • T1/2: 2 hours, then 6 to 9 hours; metabolized in the liver and excreted in urine and feces.
• Adverse Effects: Dizziness, headache, diarrhea, abdominal pain, symptoms of upper respiratory tract infection, cough, back pain, fever, muscle weakness, hypotension.

Renin Inhibitor

• New class of drugs for treating hypertension which directly inhibits renin, leading to decreased plasma renin activity and inhibiting the conversion of angiotensinogen to angiotensin I
• aliskiren (Tekturna)
• Pharmacokinetics- slowly absorbed from the GI tract, with peak levels in 3 hours. It is metabolized in the liver, with a half-life of 24 hours, and is excreted in the urine
• Contraindications- Pregnancy and lactation
• Adverse effects- Risk of hyperkalemia
• Drug-Drug Interactions- Furosemide and ACE Inhibitors

Complications

• Angioedema, rash, and cough
  • Angioedema is swelling of the pharynx, tongue, glottis
  • Client Education:
    • Monitor for rash and angioedema. Stop medication and notify provider, or call 911 for severe manifestations.
• Hyperkalemia
  • Nursing Actions: Monitor blood potassium periodically during treatment.
  • Client Education: Do not use potassium supplements or salt substitutes containing potassium. Monitor and report manifestations of hyperkalemia (paresthesias of hands and feet).
• Diarrhea
  • Dose-related
  • Seen most often in females and older adult clients
  • Nursing Actions: Monitor for dehydration, especially in older adults.
  • Client Education: Notify the provider for severe diarrhea.
• Hypotension
  • Nursing Actions: Monitor blood pressure. Advise clients to rise slowly from sitting.
  • Client Education: Avoid activities that require alertness until effects are known.

Contraindications/Precautions

• Pregnancy Risk
  • Advise clients of childbearing age to use contraception and discontinue medication if pregnancy occurs.
• Contraindicated in clients who have hyperkalemia.
• Use cautiously in older adults and clients who have asthma, other respiratory disorders, history of angioedema, diabetes mellitus, renal stenosis, hypotension, or kidney or hepatic disease.

Interactions

• Aliskiren
  • Decreases blood levels of furosemide.
    • Nursing Actions: Possible need to increase furosemide dosage.
  • Increases effect of other antihypertensive medications.
    • Nursing Actions: Monitor blood pressure for hypotension when combinations are used.
  • Atorvastatin and ketoconazole increase levels of aliskiren.
    • Nursing Actions: Monitor for hypotension if used concurrently.
  • High-fat foods reduce absorption.
    • Client Education: Do not take medication with foods high in fat.
  • Increased hyperkalemia with ACE inhibitors, potassium supplements, or potassium-sparing diuretics.
    • Nursing Actions: Monitor potassium levels and for manifestations of hyperkalemia. Avoid concurrent use.

Nursing Administration

• High-fat meals interfere with absorption
• Instruct clients to take at the same time daily away but to avoid high-fat foods at the time of administration.
• Available alone or in combination tablets with a variety of other antihypertensives (hydrochlorothiazide, a diuretic; valsartan, an ARB).

Calcium Channel Blockers

• Decrease BP, cardiac workload, and myocardial oxygen consumption
• Prototype Medications
  • Nifedipine
  • Verapamil
  • Diltiazem
• Other Medications
  • Amlodipine
  • Felodipine
  • Nicardipine

Actions

Inhibits the movement of calcium ions across the membranes of cardiac and arterial muscle cells, depressing the impulse and leading to slowed conduction, decreased myocardial contractility, and dilation of arterioles, which lowers blood pressure and decreases myocardial oxygen consumption

Complications

• NIFEDIPINE
  • Reflex tachycardia
    • Nursing Actions:
      • Monitor clients for an increased heart rate.
      • Administer a beta blocker (metoprolol) to counteract tachycardia.
  • Acute toxicity
    • Nursing Actions:
      • With excessive doses, the heart, in addition to blood vessels, is affected.
      • Monitor vital signs and ECG. Provide gastric lavage and cathartic if indicated.
      • Administer medications (norepinephrine, calcium, isoproterenol, lidocaine, and IV fluids).
      • Have equipment for cardioversion and cardiac pacer available.
  • Orthostatic hypotension and peripheral edema
    • Nursing Actions:
      • Monitor blood pressure, edema, and daily weight.
      • A diuretic can be prescribed to control edema.
    • Client Education:
      • Observe for swelling in the lower extremities, and notify the provider if it occurs.
      • Monitor for manifestations of postural hypotension (lightheadedness, dizziness). If these occur, sit or lie down. Can be minimized by getting up slowly.
• VERAPAMIL, DILTIAZEM
  • Orthostatic hypotension and peripheral edema
    • Nursing Actions:
      • Monitor blood pressure, edema, and daily weight.
      • Instruct clients to observe for swelling in the lower extremities and notify the provider if it occurs.
      • A diuretic can be prescribed to control edema.
      • Instruct clients about the manifestations of postural hypotension (lightheadedness, dizziness). If these occur, advise clients to sit or lie down. Can be minimized by getting up slowly.
  • Constipation (primarily verapamil)
    • Client Education: Increase intake of high fiber food and oral fluids, if not restricted.
  • Suppression of cardiac function
    • Bradycardia, heart failure
    • Nursing Actions: Monitor ECG, pulse rate, and rhythm.
    • Client Education: Observe for suppression of cardiac function (slow pulse, activity intolerance), and notify provider if these occur. Discontinue medication if needed.
  • Dysrhythmias
    • QRS complex is widened and QT interval is prolonged.
    • Nursing Actions: Monitor vital signs and ECG.
  • Acute toxicity
    • Resulting in hypotension, bradycardia, AV block, and ventricular tachydysrhythmias
    • Nursing Actions:
      • Monitor vital signs and ECG. Gastric lavage and cathartic can be indicated.
      • Administer medications (norepinephrine, calcium, isoproterenol, lidocaine, and IV fluids).
      • Have equipment for cardioversion and cardiac pacer available.

Contraindications/Precautions

• Pregnancy Risk
• Nifedipine is contraindicated in clients who are in cardiogenic shock.
• Use nifedipine with caution in clients who have acute MI, unstable angina, aortic stenosis, hypotension, sick sinus syndrome, and second- or third-degree AV block.
• Verapamil is contraindicated in clients who have hypotension, heart block, digoxin toxicity, severe heart failure, and during lactation.
• Use cautiously in older adults and clients who have kidney or liver disorders, mild to moderate heart failure, or GERD.

Interactions

• NIFEDIPINE
  • Beta blockers (metoprolol) are used to decrease reflex tachycardia.
    • Nursing Actions: Monitor for excessive slowing of heart rate.
  • Cimetidine, ranitidine, and grapefruit juice can lead to toxicity.
    • Nursing Actions:
      • Monitor for indications of toxicity (decrease in blood pressure, increase in heart rate, and flushing).
      • Advise clients to avoid drinking grapefruit juice.
      • Avoid concurrent use with cimetidine and ranitidine.
• VERAPAMIL, DILTIAZEM
  • Verapamil can increase digoxin levels, increasing the risk of digoxin toxicity. Digoxin can cause an additive effect and intensify AV conduction suppression.
    • Nursing Actions:
      • Monitor digoxin levels to maintain therapeutic range.
      • Monitor vital signs for bradycardia and for manifestations of AV block (a reduced ventricular rate).
  • Concurrent use of beta blockers can lead to heart failure, AV block, and bradycardia.
    • Nursing Actions:
      • Allow several hours between administration of IV verapamil and beta blockers.
      • Monitor ECG and heart rate.
  • Consuming grapefruit juice and verapamil or diltiazem can lead to toxicity.
    • Nursing Actions: Monitor for indications of toxicity (decrease in blood pressure, decrease in heart rate, and AV block). Advise clients to avoid drinking grapefruit juice.

Nursing Administration

• For IV administration of verapamil, administer injections slowly over a period of 2 to 3 min.
• Teach clients to monitor blood pressure and heart rate, as well as keep a blood pressure record.
• Withhold medication and notify provider for pulse less than 50/min and systolic blood pressure less than 90 mm Hg.
• Client Education:
  • Do not chew or crush sustained-release tablets.
  • If with angina, record pain frequency, intensity, duration, and location. Notify the provider if attacks increase in frequency, intensity, and/or duration.
  • Change positions slowly and avoid activities that require alertness until effects are known.

Prototype Calcium Channel Blocker: Diltiazem

• Indications: Treatment of essential hypertension in the extended-release form.
• Actions: Inhibits the movement of calcium ions across the membranes of cardiac and arterial muscle cells, depressing the impulse and leading to slowed conduction, decreased myocardial contractility, and dilation of arterioles, which lowers BP and decreases myocardial oxygen consumption.
• Pharmacokinetics:
  • Route: Oral, extended release
  • Onset: 30-60 min
  • Peak: 6-11 h
  • Duration: 12h
  • T1/2: 5 to 7 hours; metabolized in the liver and excreted in the urine.
• Adverse Effects: Dizziness, light-headedness, headache, peripheral edema, bradycardia, atrioventricular block, flushing, nausea.

Medications for Hypertensive Crisis

• Prototype Medication: Nitroprusside (centrally-acting vasodilator)
• Other Medications:
  • Nitroglycerin (vasodilator)
  • Nicardipine (calcium channel blocker)
  • Clevidipine (calcium channel blocker)
  • Enalaprilat (ACE inhibitor)
  • Esmolol (beta blocker)

Expected Pharmacological Action

Direct vasodilation of arteries and veins resulting in rapid reduction of blood pressure (decreased preload and afterload)

Therapeutic Uses

Hypertensive crisis

Complications

• Excessive hypotension
  • Nursing Actions:
    • Administer medication slowly because rapid administration will cause blood pressure to go down rapidly.
    • Monitor blood pressure and ECG continuously.
    • Keep client supine during administration
• Cyanide poisoning/thiocyanate toxicity
  • Headache and drowsiness and can lead to cardiac arrest
  • Nitroprusside only
  • Nursing Actions:
    • Clients who have liver dysfunction are at increased risk.
    • Risk of cyanide poisoning is reduced by administering medication for no longer than 3 days, and at a rate of 5 mcg/kg/min or less. Avoid prolonged use of nitroprusside.
    • Manifestations include weakness, disorientation, and delirium. Administer thiosulfate to reverse effects.
    • Monitor plasma levels if used for more than 3 days. Level should be maintained at less than 10 mg/dL.
    • Discontinue medication if cyanide toxicity occurs.
• Bradycardia, tachycardia, ECG changes
  • Nursing Actions: Monitor ECG for changes

Contraindications/Precautions

• Contraindicated in clients who have heart failure with reduced peripheral vascular resistance or an AV shunt.
• Use cautiously in clients who have liver and kidney disease, hypothyroidism, hypovolemia, or fluid and electrolyte imbalances, and in older adults.

Interactions

Do not administer nitroprusside in the same infusion as any other medication.

Nursing Administration

• Prepare medication by adding to diluent for IV infusion.
• Note color of solution. Solution can be light brown in color. Discard solution of any other color.
• Protect IV container and tubing from light.
• Discard medication after 24 hr.
• Monitor vital signs and ECG continuously.

Nursing Evaluation of Medication Effectiveness

Depending on therapeutic intent, effectiveness is evidenced by the following:

• Decrease in blood pressure and maintenance of normotensive blood pressure.
• Improvement of heart failure (ability to perform activities of daily living, improved breath sounds, and absence of edema).

Diuretics

Increase the excretion of sodium and water from the kidney to lower blood pressure (Figure 43.3). See Chapter 51 for a detailed discussion of these agents.

• Thiazide and thiazide-like diuretics: chlorothiazide (Diuril), hydrochlorothiazide (HydroDIURIL), methyclothiazide (generic), chlorthalidone (generic), indapamide (generic), and metolazone (Zaroxolyn)
• Potassium-sparing diuretics: amiloride (Midamor), spironolactone (Aldactone), and triamterene (Dyrenium)

Sympathetic Nervous System Blockers

• Beta-blockers: Acebutolol (Sectral), Atenolol (Tenormin), Betaxolol (generic), Bisoprolol (Zebeta), Metoprolol (Lopressor), Nadolol (Corgard), Nebivolol (Bystolic), Pindolol (generic), Propranolol (Inderal), Timolol (generic)
• Alpha- and beta-blockers: Carvedilol (Coreg), Labetalol (Trandate)
• Alpha-adrenergic blockers: Phenoxybenzamine (Dibenzyline), Phentolamine (Regitine)
• Alpha1-blockers: Doxazosin (Cardura), Prazosin (Minipress), Terazosin (generic)
• Alpha2-agonists: Clonidine (Catapres), Guanfacine (Tenex), Methyldopa (generic)

Antihypotensive Agents

• Blood Pressure-Raising Agents: Midodrine (generic), Droxidopa (Northera)
• Sympathetic adrenergic agonists or vasopressors: Dobutamine (generic), Dopamine (generic), Ephedrine (generic), Epinephrine (Adrenalin, Adrenaclick), Isoproterenol (Isuprel), Norepinephrine (Levophed), Phenylephrine (generic)

Nursing Considerations for Patients Receiving Antihypotensive Drugs

• Assess:
  • History and Physical Exam
  • Known allergy
  • Impaired kidney or liver function, pregnancy, and lactation
  • CV dysfunction; visual problems; urinary retention; and pheochromocytoma
• Baseline to include, VS, skin, weight, respirations and LS, appropriate lab values