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Pharmacologic class: Calcium channel blocker
Therapeutic class: Antihypertensive, antianginal
Pregnancy risk category C
Impedes extracellular calcium ion movement across membranes of myocardial muscle cells, depressing myocardial contractility and impulse formation; slows impulse conduction velocity and dilates coronary arteries and peripheral arterioles. Net effect is reduced cardiac workload and lower blood pressure.
Tablets (extended-release): 2.5 mg, 5 mg, 10 mg
Indications and dosages
Adults: Initially, 5 mg P.O. daily. Depending on response, may decrease to 2.5 mg or increase to a maximum of 10 mg P.O. daily at 2-week intervals.
• Hepatic impairment
• Elderly patients
• Heart failure
• Angina pectoris or vasospastic (Prinzmetal's) angina
• Hypersensitivity to drug
Use cautiously in:
• cardiac disease, arrhythmias, severe hepatic or renal impairment
• elderly patients
• pregnant or breastfeeding patients
• children (safety not established).
• Give without regard to meals.
• Make sure patient swallows tablet whole without crushing or chewing.
CNS: headache, drowsiness, dizziness, syncope, nervousness, anxiety, psychiatric disturbances, paresthesia, insomnia, asthenia, confusion, irritability
CV: chest pain, peripheral edema, hypotension, palpitations, tachycardia, angina, arrhythmias, myocardial infarction, atrioventricular block
EENT: rhinorrhea, sneezing, pharyngitis
GI: nausea, vomiting, diarrhea, constipation, abdominal discomfort, dyspepsia, abdominal cramps, flatulence, dry mouth
Musculoskeletal: back pain
Skin: dermatitis, rash, pruritus, urticaria, erythema
Other: dysgeusia, gingival hyperplasia, facial edema, thirst, warm sensation
Drug-drug. Antifungals, cimetidine, erythromycin, propranolol, ranitidine: increased felodipine blood level, increased risk of toxicity
Barbiturates, hydantoins: decreased felodipine blood level
Beta-adrenergic blockers, digoxin, disopyramide, phenytoin: bradycardia, conduction defects, heart failure
Fentanyl, nitrates, other antihypertensives, quinidine: additive hypotension
Nonsteroidal anti-inflammatory drugs: decreased antihypertensive effects
Drug-food. Grapefruit juice: increased felodipine blood level and effects
Drug-behaviors. Acute alcohol ingestion: additive hypotension
☞ Don't give to patient with heart block unless he has a pacemaker.
☞ Use extreme caution when administering to patients with pulmonary hypertension, renal insufficiency, heart failure, or compromised ventricular function (especially those receiving beta-adrenergic blockers concurrently).
• Monitor fluid intake and output, and weigh patient daily.
• Monitor ECG and vital signs. Assess for signs and symptoms of heart block.
• Assess for reflex tachycardia, angina, and sustained hypotension.
• Check hepatic profile and alkaline phosphatase level in patients with hepatic impairment.
• Tell patient drug controls but doesn't cure high blood pressure, so he should keep taking it even if he feels well.
• Instruct patient to move slowly when rising, to avoid light-headedness or dizziness from sudden blood pressure decrease.
• Explain that exercise and hot weather may increase drug's hypotensive effects.
• Tell patient to report peripheral edema, persistent headache, or flushing.
• Advise patient to use hard candy or gum if dry mouth or thirst occurs.
• Tell female patient to inform prescriber if she is pregnant or breastfeeding.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, foods, and behaviors mentioned above.
Pharmacologic: calcium channel blockers
Time/action profile (antihypertensive effect)
|PO||1 hr||2–4 hr||up to 24 hr|
Adverse Reactions/Side Effects
Central nervous system
- headache (most frequent)
- abnormal dreams
- psychiatric disturbances
Ear, Eye, Nose, Throat
- blurred vision
- disturbed equilibrium
- arrhythmias (life-threatening)
- HF (life-threatening)
- peripheral edema (most frequent)
- chest pain
- dry mouth
- ↑ liver enzymes
- sexual dysfunction
- urinary frequency
- erythema multiforme
- ↑ sweating
- weight gain
- joint stiffness
- muscle cramps
- stevens-johnson syndrome (life-threatening)
- gingival hyperplasia
Drug-Drug interactionAdditive hypotension may occur when used concurrently with fentanyl, other antihypertensives, nitrates, acute ingestion of alcohol, or quinidine.Antihypertensive effects may be ↓ by concurrent use of NSAIDs.Ketoconazole, itraconazole, propranolol, and erythromycin ↓ metabolism and ↑ blood levels and the risk of toxicity (dose ↓ may be necessary).Grapefruit juice ↑ serum levels and effect.
Availability (generic available)
- 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.
Potential Nursing DiagnosesIneffective tissue perfusion (Indications)
Acute pain (Indications)
- Do not confuse Plendil with Isordil.
- Oral: 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.
- 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, rash, 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.
- 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.
- 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.