Felodipine

Pronunciation

(fe LOE di peen)

U.S. Brand Names

Plendil®

Generic Available

Canadian Brand Names

Plendil®; Renedil®

Use

Treatment of hypertension

Pregnancy Risk Factor

Pregnancy Implications

Potentially, calcium channel blockers may prolong labor. There are no adequate or well-controlled studies in pregnant women.

Lactation

Excretion in breast milk unknown/not recommended

Contraindications

Hypersensitivity to felodipine, any component of the formulation, or other calcium channel blocker

Warnings/Precautions

Watch for hypotension and syncope (can rarely occur). Reflex tachycardia may occur. Use caution in patients with heart failure particularly with concurrent beta-blocker use. Elderly patients and patients with hepatic impairment should start off with a lower dose. Peripheral edema is the most common side effect (occurs within 2-3 weeks of starting therapy). Use caution in hepatic impairment. Safety and efficacy in children have not been established. Dosage titration should occur after 14 days on a given dose.

Adverse Reactions

>10%: Central nervous system: Headache (11% to 15%)

2% to 10%: Cardiovascular: Peripheral edema (2% to 17%), tachycardia (0.4% to 2.5%), flushing (4% to 7%)

<1% (Limited to important or life-threatening): Abdominal pain, acid regurgitation, anemia, angioedema, angina pectoris, anxiety disorders, arm pain, arrhythmia, arthralgia, back pain, bronchitis, chest pain, CHF, constipation, contusion, CVA, decreased libido, depression, diarrhea, dizziness, dry mouth, dyspnea, dysuria, epistaxis, erythema, facial edema, flatulence, flu-like illness, flushing, foot pain, gingival hyperplasia, gynecomastia, hip pain, hypotension, impotence, influenza, insomnia, irritability, knee pain, leg pain, leukocytoclastic vasculitis, MI, muscle cramps, myalgia, MI, nausea, nervousness, palpitation, paresthesia, pharyngitis, polyuria, premature beats, respiratory infection, sinusitis, somnolence, syncope, urinary frequency, urinary urgency, urticaria, visual disturbances, vomiting

Overdosage/Toxicology

Primary cardiac symptoms of calcium blocker overdose include hypotension and bradycardia. Noncardiac symptoms include confusion, stupor, nausea, vomiting, metabolic acidosis, and hyperglycemia. Treat symptomatically.

Drug Interactions

Substrate of CYP3A4 (major); Inhibits CYP2C8/9 (weak), 2D6 (weak), 3A4 (weak)

Azole antifungals may inhibit calcium channel blocker's metabolism; avoid this combination. Try an antifungal like terbinafine (if appropriate) or monitor closely for altered effect of the calcium channel blocker.

Beta-blockers may have increased pharmacokinetic or pharmacodynamic interactions with felodipine.

Calcium may reduce the calcium channel blocker's effects, particularly hypotension.

Carbamazepine significantly reduces felodipine's bioavailability; avoid this combination.

Cimetidine may inhibit felodipine metabolism (AUC increased by 50%); use caution and monitor for potential hypotension.

Cyclosporine increases felodipine's serum concentration; avoid the combination or reduce dose of felodipine and monitor blood pressure.

CYP3A4 inducers: CYP3A4 inducers may decrease the levels/effects of felodipine. Example inducers include aminoglutethimide, carbamazepine, nafcillin, nevirapine, phenobarbital, phenytoin, and rifamycins.

CYP3A4 inhibitors: May increase the levels/effects of felodipine. Example inhibitors include azole antifungals, ciprofloxacin, clarithromycin, diclofenac, doxycycline, erythromycin, imatinib, isoniazid, nefazodone, nicardipine, propofol, protease inhibitors, quinidine, and verapamil.

Erythromycin decreases felodipine's metabolism; coadministration results in a twofold increase in the AUC and half-life of felodipine; monitor for hypotension.

Nafcillin decreases plasma concentration of felodipine; avoid this combination.

Rifampin increases the metabolism of the calcium channel blocker; adjust the dose of the calcium channel blocker to maintain efficacy.

Sildenafil, tadalafil, vardenafil: Blood pressure-lowering effects may be additive; use caution.

Tacrolimus: Felodipine may increase tacrolimus serum levels; monitor.

Ethanol/Nutrition/Herb Interactions

Ethanol: Increases felodipine's absorption; watch for a greater hypotensive effect.

Food: Increased therapeutic and vasodilator side effects, including severe hypotension and myocardial ischemia, may occur if felodipine is taken with grapefruit juice; avoid concurrent use. High-fat/carbohydrate meals will increase Cmax by 60%; grapefruit juice will increase Cmax by twofold.

Herb/Nutraceutical: St John's wort may decrease felodipine levels. Avoid dong quai if using for hypertension (has estrogenic activity). Avoid ephedra, yohimbe, ginseng (may worsen hypertension). Avoid garlic (may have increased antihypertensive effect).

Mechanism of Action

Inhibits calcium ions from entering the "slow channels" or select voltage-sensitive areas of vascular smooth muscle and myocardium during depolarization, producing a relaxation of coronary vascular smooth muscle and coronary vasodilation; increases myocardial oxygen delivery in patients with vasospastic angina

Pharmacodynamics/Kinetics

Onset of action: 2-5 hours

Duration: 16-24 hours

Absorption: 100%; Absolute: 20% due to first-pass effect

Protein binding: >99%

Metabolism: Hepatic; extensive first-pass effect

Half-life elimination: 11-16 hours

Excretion: Urine (as metabolites)

Dosage

Adults: Oral: 2.5-10 mg once daily; usual initial dose: 5 mg; increase by 5 mg at 2-week intervals, as needed; maximum: 10 mg

Usual dose range (JNC 7) for hypertension: 2.5-20 mg once daily

Elderly: Begin with 2.5 mg/day

Dosing adjustment/comments in hepatic impairment: Initial: 2.5 mg/day; monitor blood pressure

Administration

Do not crush or chew extended release tablets; swallow whole.

Dietary Considerations

Should be taken without food.

Patient Education

Inform prescriber of all prescriptions, OTC medications, or herbal products you are using and any allergies you have. Do not take any new medication during therapy unless approved by prescriber. Take exactly as directed, without food. Avoid concurrent grapefruit juice and alcohol (may cause hypotension). Swallow whole, do not crush or chew. Do not alter dose or stop taking without consulting prescriber. May cause headache (consult prescriber for analgesic); nausea or vomiting (small, frequent meals, frequent mouth care, chewing gum, or sucking lozenges may help); constipation (increased dietary bulk and fluids may help); or drowsiness (use caution when driving or engaging in tasks that require alertness until response to drug is known). Report irregular heartbeat, chest pain or palpitations; persistent headache; vomiting; constipation; peripheral or facial swelling; weight gain >5 lb/week; dyspnea or respiratory changes. Pregnancy/breast-feeding precautions: Inform prescriber if you are or intend to become pregnant. Consult prescriber if breast-feeding.

Additional Information

Felodipine maintains renal and mesenteric blood flow during hemorrhagic shock in animals.

Cardiovascular Considerations

Felodipine alone or in combination with other agents is effective in the management of hypertension and angina. Felodipine has neutral effects on cardiovascular morbidity and mortality in patients with heart failure and thus is safe to use to treat hypertension and/or angina in this setting.

In the treatment of unstable angina/non-ST-segment elevation MI, a nondihydropyridine calcium antagonist (diltiazem or verapamil) may be considered in patients with continuing or frequently recurring ischemia when beta-blockers are contraindicated (Class I). Oral long-acting calcium antagonists may also be considered in addition to beta-blockers and nitrates (Class IIa).

Dental Health: Effects on Dental Treatment

Key adverse event(s) related to dental treatment: Gingival hyperplasia (fewer reports than other CCBs, resolves upon discontinuation, consultation with physician is suggested).

Dental Health: Vasoconstrictor/Local Anesthetic Precautions

No information available to require special precautions

Mental Health: Effects on Mental Status

May cause dizziness; rarely may cause nervousness, insomnia, or depression

Mental Health: Effects on Psychiatric Treatment

Carbamazepine may decrease felodipine effect

Dosage Forms

Tablet, extended release: 2.5 mg, 5 mg, 10 mg

References

Braunwald E, Antman EM, Beasley JW, et al, "ACC/AHA Guidelines for the Management of Patients With Unstable Angina and Non-ST-Segment Elevation Myocardial Infarction. A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on the Management of Patients With Unstable Angina)," J Am Coll Cardiol , 2000, 36(3):970-1062.

Chobanian AV, Bakris GL, Black HR, et al, "The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: The JNC 7 Report," JAMA , 2003, 289(19):2560-71.

Cohn JN, Ziesche S, Smith R, et al, "Effect of the Calcium Antagonist Felodipine as Supplementary Vasodilator Therapy in Patients With Chronic Heart Failure Treated With Enalapril: V-HeFT III. Vasodilator-Heart Failure Trial (V-HeFT) Study Group," Circulation , 1997, 96(3):856-63.

Steele RM, Schuna AA, and Schreiber RT, "Calcium Antagonist-Induced Gingival Hyperplasia," Ann Intern Med , 1994, 120(8):663-4.

International Brand Names

Agon® (AU, NZ); Auronal® (RO); Felobeta® (DE); Felo Biochemie® (DE); Felocor® (DE); Feloday® (IT); Felodil® (CH); Felodin® (DK); Felodipin 1A Pharma® (DE); Felodipin AbZ® (DE); Felodipin AL® (DE); Felodipin Alpharma® (DK); Felodipin AZU® (DE); Felodipin Biochemie® (DK, SE); Felodipin dura® (DE); Felodipine "Cross Pharma"® (DK); Felodipine Hexal® (ZA); Felodipin Gea® (DK); Felodipin GEA Retard® (SE); Felodipin Heumann® (DE); Felodipin NM Pharma® (SE); Felodipin-ratiopharm® (DE); Felodipin ratiopharm® (DK, SE); Felodipin Sandoz® (DE); Felodipin Stada® (DE, SE); Felodipin TAD® (DE); felodipin von ct® (DE); Felodur® (AU); Felogamma® (DE); Felogard® (IN); Felo® (NZ); Felo-Puren® (DE); Fensel® (ES); Flodil® (FR); Hydac® (FI); Modip® (DE); Munobal® (AR, AT, CH, DE, MX); Nirmadil® (ID); Penedil® (IL); Perfudal® (ES); Plendil® (AR, AT, AU, BE, BG, CA, CH, CY, CZ, DK, ES, FI, GB, HK, HU, ID, IE, IT, KW, LB, LU, MT, MX, NL, NO, NZ, PL, RO, RU, SE, SG, TH, TR, YU, ZA); Plendur® (DK); Presid® (CZ); Preslow® (PT); Prevex® (IT); Renedil® (BE, CA, LU, NL); Splendil® (BR, CL, JP)

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