Felodipine

Pronunciation: feh-LOW-dih-peen
Class: Calcium channel blocking agent

Trade Names

Plendil
- Tablets, extended release 2.5 mg
- Tablets, extended release 5 mg
- Tablets, extended release 10 mg

Pharmacology

Inhibits movement of calcium ions across cell membrane in systemic and coronary vascular smooth muscle, altering contractile process.

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Pharmacokinetics

Absorption

Systemic bioavailability is about 20% and T _max is 2.5 to 5 h. C _max is increased about 60% and AUC is unchanged with a high fat or carbohydrate meal.

Distribution

Vd is about 10 L/kg and it is more than 99% bound to plasma proteins.

Metabolism

Extensive first pass metabolism; 6 metabolites account for 23% of activity.

Elimination

The t _{1/ 2} is 11 to 16 h; 70% of the drug is eliminated in the urine and 10% in the feces.

Onset

2 to 5 h.

Duration

24 h (during chronic administration).

Special Populations

About 60% reduction in Cl.

Plasma concentrations of felodipine increase with age.

Indications and Usage

Treatment of hypertension.

Contraindications

Standard considerations.

Dosage and Administration

PO The recommended starting dose is 5 mg once daily. Depending on patient response, the dose can be decreased to 2.5 mg or increased to 10 mg once daily.

PO Recommended starting dose 2.5 mg once daily.

General Advice

• Doses more than 10 mg/day increased BP response but a large increase in rate of peripheral edema and other vasodilatory adverse events.
• Dosage adjustments generally should occur at intervals of no less than 2 wk.
• Administer consistently with meals or on an empty stomach.
• Extended release tablets: swallow whole; do not crush, chew, or break.

Storage/Stability

Store tablets below 86° F. Keep tightly closed. Protect from light.

Drug Interactions

Felodipine plasma concentrations may be reduced in epileptic patients, decreasing the therapeutic effects. Alternative therapy should be considered.

Metoprolol plasma levels may be increased.

Because of an increase in felodipine bioavailability or decrease in metabolism, felodipine plasma levels may be elevated several-fold, increasing the pharmacologic and adverse effects.

Felodipine plasma levels may be elevated, increasing the pharmacologic and adverse effects.

May have additive effects.

Blood levels of tacrolimus may be elevated, increasing the risk of side effects.

Laboratory Test Interactions

None well documented.

Adverse Reactions

Cardiovascular

Palpitation (at least 1.5%).

CNS

Asthenia, dizziness, headache, paresthesia (at least 1.5%).

Dermatologic

Flushing, rash (at least 1.5%).

EENT

Rhinorrhea, sneezing (at least 1.5%).

GI

Constipation, dyspepsia, nausea (at least 1.5%).

Respiratory

Cough, upper respiratory infection (at least 1.5%).

Miscellaneous

Peripheral edema, warm sensation (at least 1.5%).

Precautions

Pregnancy

Category C .

Lactation

Undetermined.

Children

Safety and efficacy not established.

Elderly

Consider starting at low end of dosing range, reflecting the higher frequency of decreased hepatic, renal, or cardiac function, and comorbidity.

Hepatic Function

May have elevated felodipine plasma concentrations and may respond to lower doses.

Heart failure

Use with caution, especially in combination with a beta-blocker.

Hypotension

May occasionally precipitate significant hypotension and, rarely, syncope. Reflex tachycardia may occur, which may precipitate angina pectoris in susceptible patients.

Overdosage

Symptoms

Excessive peripheral vasodilation with marked hypotension, bradycardia.

Patient Information

• Advise patient that dose of medication may be adjusted to obtain max benefit.
• Advise patient to take once daily regularly with food or on an empty stomach. Caution patient to swallow tablets whole and not to crush, chew, cut, or break.
• Inform patient that drug controls, but does not cure, hypertension or angina and to continue taking as prescribed even when BP is not elevated or angina symptoms are not present.
• Caution patient not to change or stop taking the dose unless advised by health care provider.
• Instruct patient to continue taking other BP medications as prescribed by health care provider.
• Instruct patient who also has angina to notify health care provider if frequency or severity of chest pain, or need for sublingual nitroglycerin appears to be increasing.
• Instruct patient in BP and pulse measurement skills.
• Advise hypertensive patient to monitor and record BP and pulse at home and to inform health care provider if abnormal measurements are noted. Also advise patient to take record of BP and pulse to each follow-up visit.
• Instruct patient to lie or sit down if experiencing dizziness or lightheadedness while standing.
• Advise patient to notify health care provider if any of the following occur: frequent episodes of dizziness when arising, swelling of lower legs or ankles, persistent fatigue, any other unusual or unexplained symptoms or signs.
• Advise patient that medication can cause gum swelling but that good dental hygiene reduces the risk and severity.
• Emphasize to hypertensive patient the importance of other modalities on BP: weight control, regular exercise, smoking cessation, and moderate intake of alcohol and salt.

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