Inspra


eplerenone

Inspra

Pharmacologic class: Aldosterone receptor blocker

Therapeutic class: Antihypertensive

Pregnancy risk category B

Action

Binds to and blocks aldosterone receptors, disrupting normal sodium and water reabsorption and causing sodium and water excretion to increase. These actions reduce blood volume and blood pressure.

Availability

Tablets: 25 mg, 50 mg

Indications and dosages

➣ Hypertension

Adults: 50 mg/day P.O. as a single dose. After 4-week trial, may increase to 50 mg P.O. b.i.d. if necessary.

➣ Heart failure; post-myocardial infarction (MI)

Adults: Initially, 25 mg P.O. once daily. After 4 weeks, may increase to maximum dosage of 50 mg P.O. once daily.

Contraindications

• Hypersensitivity to drug

• Hyperkalemia

• Potassium supplements or potassium-sparing diuretics

• Type 2 diabetes mellitus with microalbuminuria

• Severe renal impairment

Precautions

Use cautiously in:

• hepatic impairment

• pregnant or breastfeeding patients

• children (safety and efficacy not established).

Administration

• Give with or without food.

• Know that drug may be given alone or with other antihypertensives.

Adverse reactions

CNS: headache, dizziness, fatigue

CV: angina, MI

GI: diarrhea, abdominal pain

GU: albuminuria, vaginal bleeding, changes in sexual function, gynecomastia and breast pain (in men)

Metabolic: hypercholesterolemia, hyperkalemia

Respiratory: cough

Other: flulike symptoms

Interactions

Drug-drug. Angiotensin-converting enzyme inhibitors, potassium-sparing diuretics, potassium supplements: increased risk of hyperkalemia

CYP450-3A4 inhibitors: serious toxic effects

Lithium: increased risk of toxicity

Nonsteroidal antiinflammatory drugs: decreased hypertensive effect of eplerenone

Patient monitoring

• Monitor electrolyte levels, and watch for signs and symptoms of hyperkalemia.

• Check vital signs, and ask patient about chest pain.

• Monitor lipid panel.

• Assess for new onset of persistent dry cough or flulike symptoms.

Patient teaching

See Advise patient to immediately report chest pain, flulike symptoms, or persistent dry cough.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.

• Inform patient that drug may affect sexual function. Encourage him to discuss this issue with prescriber.

• Advise female patient to discuss pregnancy or breastfeeding with prescriber before starting drug.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs mentioned above.

eplerenone

(e-ple-re-none) eplerenone,

Inspra

(trade name)

Classification

Therapeutic: antihypertensives
Pharmacologic: aldosterone antagonists
Pregnancy Category: B

Indications

Hypertension (alone, or with other agents).LV systolic dysfunction and evidence of HF post-MI.

Action

Blocks the effects of aldosterone by attaching to mineralocorticoid receptors.

Therapeutic effects

Lowering of BP.Improves survival in patients with evidence of HF post-MI.

Pharmacokinetics

Absorption: Well absorbed following oral administration.Distribution: Unknown.Metabolism and Excretion: Mostly metabolized by the liver (CYP3A4 enzyme system); <5% excreted unchanged by the kidneys.Half-life: 4–6 hr.

Time/action profile (antihypertensive effect)

ROUTEONSETPEAKDURATION
POunknown4 wkunknown

Contraindications/Precautions

Contraindicated in: Serum potassium >5.5 mEq/L;Type 2 diabetes with microalbuminuria (for patients with HTN; ↑ risk of hyperkalemia);Serum creatinine >2 mg/dL in males or > 1.8 mg/dL in females (for patients with HTN);CCr ≤30 mL/min (for all patients); CCr <50 mL/min (for patients with HTN);Concurrent use of potassium supplements or potassium-sparing diuretics (for patients with HTN);Concurrent use of strong inhibitors of the CYP3A4 enzyme system (ketoconazole, itraconazole, nefazodone, clarithromycin, ritonavir, or nelfinavir); Lactation: Lactation.Use Cautiously in: Severe hepatic impairment; Obstetric: Use only if clearly needed; Pediatric: Safety not established.

Adverse Reactions/Side Effects

Central nervous system

  • dizziness
  • fatigue

Gastrointestinal

  • abnormal liver function tests
  • abdominal pain
  • diarrhea

Genitourinary

  • albuminuria

Endocrinologic

  • abnormal vaginal bleeding
  • gynecomastia

Fluid and Electrolyte

  • hyperkalemia (life-threatening)

Metabolic

  • hypercholesterolemia
  • hypertriglyceridemia

Miscellaneous

  • flu-like symptoms

Interactions

Drug-Drug interaction

Concurrent use of strong inhibitors of the CYP3A4 enzyme system (ketoconazole, itraconazole, nefazodone, clarithromycin, ritonavir, or nelfinavir ) significantly ↑ effects of eplerenone; concurrent use contraindicated. Concurrent use of weak inhibitors of the CYP3A4 enzyme system (erythromycin, saquinavir, fluconazole, verapamil ) may ↑ effects of eplerenone; initial dose of eplerenone should be ↓ by 50%.NSAIDs may ↓ antihypertensive effects.Concurrent use of ACE inhibitors or Angiotensin II receptor blockers may ↑ risk of hyperkalemia.

Route/Dosage

Hypertension

Oral (Adults) 50 mg daily initially; may be ↑ to 50 mg twice daily; Patients receiving concurrent moderate CYP3A4 inhibitors (erythromycin, saquinavir, verapamil, fluconazole)—25 mg once daily initially.

HF Post-MI

Oral (Adults) 25 mg daily initially; ↑ in 4 wk to 50 mg daily; subsequent dose adjustments may need to be made based on serum potassium concentrations.

Availability (generic available)

Tablets: 25 mg, 50 mg

Nursing implications

Nursing assessment

  • Monitor BP periodically during therapy.
  • Monitor prescription refills to determine adherence.
  • Lab Test Considerations: May cause hyperkalemia. Monitor serum potassium levels prior to starting therapy, within the first wk, at 1 mo following start of therapy or dose adjustment and periodically thereafter. Monitor serum potassium and serum creatinine in 3–7 days in patients who start taking a moderate CYP3A4 inhibitor.
    • May cause ↓ serum sodium and ↑ serum triglyceride, cholesterol, ALT, GGT, creatinine, and uric acid levels.

Potential Nursing Diagnoses

Decreased cardiac output (Indications)
Noncompliance (Patient/Family Teaching)

Implementation

  • Do not confuse Inspra with Spiriva.
  • PO: Administer once daily. May be increased to twice daily if response is inadequate.

Patient/Family Teaching

  • Instruct patient to take medication as directed at the same time each day, even if feeling well.
  • Encourage patient to comply with additional interventions for hypertension (weight reduction, discontinuation of smoking, moderation of alcohol consumption, regular exercise, stress management). Medication controls, but does not cure, hypertension.
  • Instruct patient and family on correct technique for monitoring BP. Advise them to monitor BP at least weekly, and notify health care professional of significant changes.
  • Inform patient not to use potassium supplements, salt substitutes containing potassium, or other Rx, OTC, or herbal products without consulting health care professional.
  • May cause dizziness. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
  • Advise patient to notify health care professional if dizziness, diarrhea, vomiting, rapid or irregular heartbeat, lower extremity edema, or difficulty breathing occur.
  • Advise patient to inform health care professional of treatment regimen prior to treatment or surgery.
  • Advise patient to notify health care professional if pregnancy is planned or suspected. Advise patient to avoid breast feeding during therapy.
  • Emphasize the importance of follow-up exams to check serum potassium.

Evaluation/Desired Outcomes

  • Decrease in BP without appearance of side effects.
  • Improvement in survival in patients with evidence of HF post-MI.

Inspra

(ĭn′sprə) A trademark for the drug eplerenone.