Calcium Channel Blocker
Treatment of hypertension, congestive heart failure
Hypersensitivity to felodipine, any component, or other calcium channel
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). Safety and efficacy in children
have not been established. Dosage titration should occur after 14 days on a
2% to 10%:
Cardiovascular: Peripheral edema (2% to 17%), tachycardia (0.4% to 2.5%),
flushing (4% to 7%)
Central nervous system: Headache (11% to 15%)
Gastrointestinal: Gingival hyperplasia
0.5% to 1.5%
<1% (Limited to important or life-threatening symptoms): Chest pain,
facial edema, flu-like illness, myocardial infarction, hypotension, syncope,
angina pectoris, arrhythmia, premature beats, abdominal pain, diarrhea,
vomiting, dry mouth, flatulence, acid, MI, CVA, CHF, regurgitation,
gynecomastia, anemia, arthralgia, back pain, leg pain, foot pain, muscle cramps,
myalgia, arm pain, knee pain, hip pain, insomnia, depression, anxiety disorders,
irritability, nervousness, somnolence, decreased libido, dyspnea, pharyngitis,
bronchitis, influenza, sinusitis, epistaxis, respiratory infection, contusion,
erythema, urticaria, visual disturbances, impotence, urinary frequency, urinary
urgency, dysuria, polyuria, gingival hyperplasia, flushing, palpitations,
nausea, constipation, dizziness, paresthesias
The primary cardiac symptoms of calcium blocker overdose include hypotension
and bradycardia. The hypotension is caused by peripheral vasodilation,
myocardial depression, and bradycardia. Bradycardia results from sinus
bradycardia, second- or third-degree atrioventricular block, or sinus arrest
with junctional rhythm. Intraventricular conduction is usually not affected so
QRS duration is normal (verapamil does prolong the P-R interval and bepridil
prolongs the Q-T and may cause ventricular arrhythmias, including torsade de
In a few reported cases, overdose with calcium channel blockers has been
associated with hypotension and bradycardia, initially refractory to atropine
but becoming more responsive to this agent when larger doses (approaching 1
g/hour for more than 24 hours) of calcium chloride was administered.
CYP3A3/4 enzyme substrate
Beta-blockers may have increased pharmacokinetic or pharmacodynamic
interactions with felodipine.
Calcium may reduce the calcium channel blocker's effects, particularly
Carbamazepine significantly reduces felodipine's bioavailability; avoid this
Cimetidine may inhibit felodipine metabolism (AUC increased 50%); use caution
Cyclosporine increases felodipine's serum concentration; avoid the
combination or reduce dose of felodipine and monitor blood pressure.
Ethanol increases felodipine's absorption; watch for a greater hypotensive
Erythromycin decreases felodipine's metabolism; monitor blood pressure.
Grapefruit juice increases the bioavailability of felodipine; monitor for
altered felodipine effects.
Nafcillin decreases plasma concentration of felodipine; avoid this
Rifampin increases the metabolism of the calcium channel blocker; adjust the
dose of the calcium channel blocker to maintain efficacy.
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
Onset of effect: 2-5 hours
Duration: 16-24 hours
Absorption: 100%; absolute: 20% due to first-pass effect
Protein binding: >99%
Metabolism: >99% in liver
Half-life: 11-16 hours
Elimination: In urine as metabolites
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
Elderly: Begin with 2.5 mg/day
Dosing adjustment/comments in hepatic impairment: Begin with 2.5
mg/day; do not use doses >10 mg/day
Should be taken without food; the bioavailability of felodipine is influenced
by the presence of food and has been shown to increase more than twofold when
taken with concentrated grapefruit juice
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
|Mental Health: Effects
on Mental Status|
May cause dizziness; rarely may cause nervousness, insomnia, or
Effects on Psychiatric
Carbamazepine may decrease felodipine effect
|Dental Health: Local
No information available to require special precautions
Effects on Dental Treatment|
Calcium channel blockers cause gingival hyperplasia in approximately 1% of
patients. There have been fewer reports with felodipine than with other CCBs.
The hyperplasia will disappear with cessation of drug therapy. Consultation with
physician is suggested.
Take without food. Take as prescribed; do not stop abruptly without
consulting prescriber immediately. Swallow whole; do not crush or chew. You may
experience headache (if unrelieved, consult prescriber), nausea or vomiting
(frequent small meals may help), constipation (increased dietary bulk and fluids
may help), depression (should resolve when drug is discontinued). May cause
dizziness or drowsiness; use caution when driving or engaging in tasks that
require alertness until response to drug is known. Report any chest pain or
swelling of hands or feet, respiratory distress, sudden weight gain, or
unresolved constipation. Pregnancy/breast-feeding precautions: Inform
prescriber if you are or intend to be pregnant. Consult prescriber if
Do not crush extended release tablets
Tablet, extended release: 2.5 mg, 5 mg, 10 mg
Buur T, Larsson R, Regardh CG, et al,
"Pharmacokinetics of Felodipine in Chronic Hemodialysis Patients," J Clin
Pharmacol, 1991, 31(8):709-13.
Neuvonen PJ and Suhonen R, "Itraconazole Interacts With Felodipine," J Am
Acad Dermatol, 1995, 33(1):134-5.
Todd PA and Faulds D,
"Felodipine. A Review of the Pharmacology and Therapeutic Use of the Extended Release Formulation in Cardiovascular Disorders,"
Drugs, 1992, 44(2):251-77.
Wade JR and Sambol NC,
"Felodipine Population Dose-Response and Concentration-Response Relationships in Patients With Essential Hypertension,"
Clin Pharmacol Ther, 1995, 57(5):569-81.
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