felodipine

General

Pronunciation:
fe-loe-di-peen


Trade Name(s)

  • Plendil Canadian Trade name

Ther. Class.

antianginals

antihypertensives

Pharm. Class.

calcium channel blockers

Indications

Management of hypertension, angina pectoris, and vasospastic (Prinzmetal's) angina.

Action

Inhibits the transport of calcium into myocardial and vascular smooth muscle cells, resulting in inhibition of excitation-contraction coupling and subsequent contraction.

Therapeutic Effect(s):

  • Systemic vasodilation resulting in decreased BP.
  • Coronary vasodilation resulting in decreased frequency and severity of attacks of angina.

Pharmacokinetics

Absorption: Well absorbed after oral administration, but extensively metabolized, resulting in ↓ bioavailability.

Distribution: Unknown.

Protein Binding: >99%.

Metabolism and Excretion: Mostly metabolized; minimal amounts excreted unchanged by kidneys.

Half-life: 11–16 hr.

TIME/ACTION PROFILE (antihypertensive effect)

ROUTEONSETPEAKDURATION
PO 1 hr 2–4 hrup to 24 hr

Contraindication/Precautions

Contraindicated in:

  • Hypersensitivity (cross-sensitivity may occur);
  • Sick sinus syndrome;
  • 2nd- or 3rd-degree AV block (unless an artificial pacemaker is in place);
  • Systolic BP <90 mm Hg.

Use Cautiously in:

  • Severe hepatic impairment (dose ↓ recommended);
  • Geri:  Dose ↓ recommended; ↑ risk of hypotension;
  • Severe renal impairment;
  • History of serious ventricular arrhythmias or HF;
  • OB:  Lactation: Pedi:  Safety not established.

Adverse Reactions/Side Effects

CV: peripheral edema, ARRHYTHMIAS, chest pain, HF, hypotension, palpitations, syncope, tachycardia

Derm: ↑ sweating, dermatitis, erythema multiforme, flushing, photosensitivity, pruritus/urticaria, rash

EENT: blurred vision, disturbed equilibrium, epistaxis, tinnitus

Endo: gynecomastia, hyperglycemia

GI: ↑ liver enzymes, anorexia, constipation, diarrhea, dry mouth, dysgeusia, dyspepsia, nausea, vomiting

GU: dysuria, nocturia, polyuria, sexual dysfunction, urinary frequency

Hemat: anemia, leukopenia, thrombocytopenia

Metabolic: weight gain

MS: joint stiffness, muscle cramps

Neuro: headache, abnormal dreams, anxiety, confusion, dizziness, drowsiness, nervousness, paresthesia, psychiatric disturbances, tremor, weakness.

Resp: cough, dyspnea

Misc: gingival hyperplasia, STEVENS-JOHNSON SYNDROME

* CAPITALS indicate life-threatening.
Underline indicate most frequent.

Interactions

Drug-Drug

Drug-Food:

Grapefruit juice ↑ serum levels and effect.

Route/Dosage

PO (Adults): 5 mg/day (2.5 mg/day in geriatric patients); may ↑ every 2 wk (range 5–10 mg/day; not to exceed 10 mg/day).

Availability (generic available)

Extended-release tablets: 2.5 mg, 5 mg, 10 mg

Assessment

  • Monitor BP and pulse before therapy, during dosage titration, and periodically during therapy. Monitor ECG periodically during prolonged therapy.
    • Monitor intake and output ratios and daily weight. Assess for signs of HF (peripheral edema, rales/crackles, dyspnea, weight gain, jugular venous distention).
  • Assess for rash periodically during therapy. May cause Stevens-Johnson syndrome. Discontinue therapy if severe or if accompanied with fever, general malaise, fatigue, muscle or joint aches, blisters, oral lesions, conjunctivitis, hepatitis, and/or eosinophilia.
  • Angina: Assess location, duration, intensity, and precipitating factors of patient's anginal pain.
  • Hypertension: Check frequency of refills to monitor adherence.

Lab Test Considerations:

Total serum calcium concentrations are not affected by calcium channel blockers.

  • Monitor serum potassium periodically. Hypokalemia ↑ risk of arrhythmias and should be corrected.
  • Monitor renal and hepatic functions periodically during long-term therapy. May cause ↑ in hepatic enzymes after several days of therapy, which return to normal upon discontinuation of therapy.

Implementation

  • PO May be administered without regard to meals. May be administered with meals if GI irritation becomes a problem.
  • Swallow tablets whole; do not break, crush, or chew. Empty tablets that appear in stool are not significant.

Patient/Family Teaching

  • Advise patient to take medication as directed, even if feeling well. If a dose is missed, take as soon as possible unless almost time for next dose; do not double doses. May need to be discontinued gradually.

    • Instruct patient on correct technique for monitoring pulse. Instruct patient to contact health care professional if heart rate is <50 bpm.
    • Advise patient to avoid grapefruit or grapefruit juice during therapy.
    • Caution patient to change positions slowly to minimize orthostatic hypotension.
    • May cause drowsiness or dizziness. Advise patient to avoid driving or other activities requiring alertness until response to the medication is known.
    • Instruct patient on importance of maintaining good dental hygiene and seeing dentist frequently for teeth cleaning to prevent tenderness, bleeding, and gingival hyperplasia (gum enlargement).
    • Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to avoid concurrent use of alcohol or OTC medications and herbal products, especially cold preparations, without consulting health care professional.
    • Advise patient to notify health care professional if rash, irregular heartbeat, dyspnea, swelling of hands and feet, pronounced dizziness, nausea, constipation, or hypotension occurs or if headache is severe or persistent.
    • Caution patient to wear protective clothing and to use sunscreen to prevent photosensitivity reactions.
    • Advise patient to inform health care professional of medication regimen before treatment or surgery.
    • Advise patient to notify health care professional if pregnancy is planned or suspected or if breast feeding.
  • Angina:

    Instruct patient on concurrent nitrate or beta-blocker therapy to continue taking both medications as directed and to use SL nitroglycerin as needed for anginal attacks.

    • Advise patient to contact health care professional if chest pain does not improve or worsens after therapy; occurs with diaphoresis or shortness of breath; or if severe, persistent headache occurs.
    • Caution patient to discuss exercise restrictions with health care professional before exertion.
  • Hypertension:

    Encourage patient to comply with other interventions for hypertension (weight reduction, low-sodium diet, smoking cessation, moderation of alcohol consumption, regular exercise, and stress management). Medication controls but does not cure hypertension.

    • Instruct patient and family in proper technique for monitoring BP. Advise patient to take BP weekly and to report significant changes.

Evaluation/Desired Outcomes

  • Decrease in BP.
  • Decrease in frequency and severity of anginal attacks.

    • Decrease in need for nitrate therapy.
    • Increase in activity tolerance and sense of well-being.

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