DIGOXIN

DIGOXIN- digoxin injection
HF Acquisition Co LLC, DBA HealthFirst

HIGHLIGHTS OF PRESCRIBING INFORMATION


These highlights do not include all the information needed to use DIGOXIN INJECTION safely and effectively. See full prescribing information for DIGOXIN INJECTION.
DIGOXIN Injection, for intravenous or intramuscular use
Initial U.S. Approval: 1954

INDICATIONS AND USAGE

Digoxin is a cardiac glycoside indicated for:

Treatment of mild to moderate heart failure in adults. (1.1)
Control of resting ventricular rate in adults with chronic atrial fibrillation. (1.2)

DOSAGE AND ADMINISTRATION

Digoxin dose is based on patient-specific factors (age, lean body weight, renal function, etc.). See full prescribing information. Monitor for toxicity and therapeutic effect. (2)

Intravenous administration is preferable to intramuscular. Avoid bolus administration. (2)

DOSAGE FORMS AND STRENGTHS

Digoxin Injection: Ampuls containing 500 mcg (0.5 mg) in 2 mL. (3)

CONTRAINDICATIONS

Ventricular fibrillation. (4)
Known hypersensitivity to digoxin or other forms of digitalis. (4)

WARNINGS AND PRECAUTIONS

Risk of rapid ventricular response leading to ventricular fibrillation in patients with AV accessory pathway. (5.1)
Risk of advanced or complete heart block in patients with sinus node disease and AV block. (5.2)
Digoxin toxicity: Indicated by nausea, vomiting, visual disturbances, and cardiac arrhythmias. Advanced age, low body weight, impaired renal function and electrolyte abnormalities predispose to toxicity. (5.3)
Risk of ventricular arrhythmias during electrical cardioversion. (5.4)
Not recommended in patients with acute myocardial infarction (5.5)
Avoid digoxin in patients with myocarditis. (5.6)

ADVERSE REACTIONS

The overall incidence of adverse reactions with digoxin has been reported as 5-20%, with 15-20% of adverse events considered serious. Cardiac toxicity accounts for about one-half, gastrointestinal disturbances for about one-fourth, and CNS and other toxicity for about one-fourth of these adverse events. (6.1)

To report SUSPECTED ADVERSE REACTIONS, contact West-Ward Pharmaceuticals Corp. at 1-877-845-0689 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

DRUG INTERACTIONS

PGP Inducers/Inhibitors: Drugs that induce or inhibit PGP have the potential to alter digoxin pharmacokinetics. (7.1)
The potential for drug-drug interactions must be considered prior to and during drug therapy. See full prescribing information. (7.2, 7.3, 12.3)

USE IN SPECIFIC POPULATIONS

Pregnant patients: It is unknown whether use during pregnancy can cause fetal harm. (8.1)
Pediatric patients: Newborn infants display variability in tolerance to digoxin. (8.4)
Geriatric patients: Consider renal function in dosage selection, and carefully monitor for side effects. (8.5)
Renal impairment: Digoxin is excreted by the kidneys. Consider renal function during dosage selection. (8.6)

See 17 for PATIENT COUNSELING INFORMATION.

Revised: 1/2017

FULL PRECRIBING INFORMATION : CONTENTS*

1 INDICATIONS & USAGE
1.1 Heart Failure in Adults
1.2 Atrial Fibrillation in Adults
2 DOSAGE & ADMINISTRATION
2.1 Important Dosing and Administration Information
2.2 Loading Dosing Regimen in Adults and Pediatric Patients Over 10 Years Old
2.3 Maintenance Dosing in Adults and Pediatric Patients Over 10 Years Old
2.4 Monitoring to Assess Safety, Efficacy, and Therapeutic Blood Levels
2.5 Switching from Intravenous Digoxin to Oral Digoxin
3 DOSAGE FORMS & STRENGTHS
4 CONTRAINDICATIONS
5 WARNINGS & PRECAUTIONS
5.1 Ventricular Fibrillation in Patients With Accessory AV Pathway (Wolff-Parkinson-White Syndrome)
5.2 Sinus Bradycardia and Sino-atrial Block
5.3 Digoxin Toxicity
5.4 Risk of Ventricular Arrhythmias During Electrical Cardioversion
5.5 Risk of Ischemia in Patients With Acute Myocardial Infarction
5.6 Vasoconstriction in Patients With Myocarditis
5.7 Decreased Cardiac Output in Patients With Preserved Left Ventricular Systolic Function
5.8 Reduced Efficacy in Patients With Hypocalcemia
5.9 Altered Response in Thyroid Disorders and Hypermetabolic States
6 ADVERSE REACTIONS
6.1 Clinical Trials Experience
7 DRUG INTERACTIONSDRUG INTERACTIONS
7.1 P-Glycoprotein (PGP) Inducers/Inhibitors
7.2 Pharmacokinetic Drug Interactions
7.3 Potentially Significant Pharmacodynamic Drug Interactions
7.4 Drug/Laboratory Test Interactions
8 USE IN SPECIFIC POPULATIONS
8.1 Pregnancy
8.2 Labor and Delivery
8.3 Nursing Mothers
8.4 Pediatric Use
8.5 Geriatric Use
8.6 Renal Impairment
8.7 Hepatic Impairment
8.8 Malabsorption
10 OVERDOSAGE
10.1 Signs and Symptoms in Adults
10.2 Treatment
11 DESCRIPTION
12 CLINICAL PHARMACOLOGY
12.1 Mechanism of Action
12.2 Pharmacodynamics
12.3 Pharmacokinetics
13 NONCLINICAL TOXICOLOGY
13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility
14 CLINICAL STUDIES
14.1 Chronic Heart Failure
14.2 Chronic Atrial Fibrillation
16 HOW SUPPLIED/STORAGE & HANDLING
17 PATIENT COUNSELING INFORMATION

* Sections or subsections omitted from the full prescribing information are not listed.

1. INDICATIONS & USAGE

1.1 Heart Failure in Adults

Digoxin is indicated for the treatment of mild to moderate heart failure in adults. Digoxin increases left ventricular ejection fraction and improves heart failure symptoms, as evidenced by improved exercise capacity and decreased heart failure-related hospitalizations and emergency care, while having no effect on mortality. Where possible, digoxin should be used in combination with a diuretic and an angiotensin-converting enzyme (ACE) inhibitor.

1.2 Atrial Fibrillation in Adults

Digoxin is indicated for the control of ventricular response rate in adult patients with chronic atrial fibrillation.

2. DOSAGE & ADMINISTRATION

2.1 Important Dosing and Administration Information

In selecting a digoxin dosing regimen, it is important to consider factors that affect digoxin blood levels (e.g., body weight, age, renal function, concomitant drugs) since toxic levels of digoxin are only slightly higher than therapeutic levels. Dosing can be either initiated with a loading dose followed by maintenance dosing if rapid titration is desired or initiated with maintenance dosing without a loading dose.

Parenteral administration of digoxin should be used only when the need for rapid digitalization is urgent or when the drug cannot be taken orally. Intramuscular injection can lead to severe pain at the injection site, thus intravenous administration is preferred. If the drug must be administered by the intramuscular route, it should be injected deep into the muscle followed by massage. For adults, no more than 500 mcg of Digoxin Injection should be injected into a single site. For pediatric patients, see the full prescribing information for pediatric digoxin injection (not available from West-Ward) for specific recommendations.

Administer the dose over a period of 5 minutes or longer and avoid bolus administration to prevent systemic and coronary vasoconstriction. Mixing of Digoxin Injection with other drugs in the same container or simultaneous administration in the same intravenous line is not recommended.

Digoxin Injection can be administered undiluted or diluted with a 4-fold or greater volume of Sterile Water for Injection, 0.9% Sodium Chloride Injection, or 5% Dextrose Injection. The use of less than a 4-fold volume of diluent could lead to precipitation of the digoxin. Immediate use of the diluted product is recommended.

If tuberculin syringes are used to measure very small doses do not flush with the parenteral solution after its contents are expelled into an indwelling vascular catheter to avoid overadministration of digoxin.

Consider interruption or reduction in digoxin dose prior to electrical cardioversion [see WARNINGS & PRECAUTIONS(5.4)].

2.2 Loading Dosing Regimen in Adults and Pediatric Patients Over 10 Years Old

Table 1. Recommended Digoxin Injection Loading Dose

DOSAGE 1
(click image for full-size original)

mcg = microgram

2.3 Maintenance Dosing in Adults and Pediatric Patients Over 10 Years Old

The maintenance dose is based on lean body weight, renal function, age, and concomitant products [see CLINICAL PHARMACOLOGY (12.3)].

The recommended starting maintenance dose in adults and pediatric patients over 10 years old with normal renal function is given in Table 2. Doses may be increased every 2 weeks according to clinical response, serum drug levels, and toxicity.

Table 2. Recommended Starting Digoxin Injection Maintenance Dosage in Adults and Pediatric Patients Over 10 Years Old

DOSAGE 2
(click image for full-size original)

mcg = microgram

Table 3 provides the recommended (once daily) maintenance dose for adults and pediatric patients over 10 years old according to lean body weight and renal function. The doses are based on studies in adult patients with heart failure. Alternatively, the maintenance dose may be estimated by the following formula (peak body stores lost each day through elimination):

Total Maintenance Dose = Loading Dose (i.e., Peak Body Stores) x % Daily Loss/100 (% Daily Loss = 14 + Creatinine clearance/5)

Reduce the dose of digoxin in patients whose lean weight is an abnormally small fraction of their total body mass because of obesity or edema.

Table 3. Recommended Maintenance Dose (in micrograms given once daily) of Digoxin Injection in Pediatric Patients Over 10 Years Old and Adults by Lean Body Weight and by Renal Function

DOSAGE 3
(click image for full-size original)

a For adults, creatinine clearance was corrected to 70-kg body weight or 1.73 m2 body surface area. If only serum creatinine concentrations (Scr) are available, a corrected Ccr may be estimated in men as (140 – Age)/Scr. For women, this result should be multiplied by 0.85.

For pediatric patients, the modified Schwartz equation may be used. The formula is based on height in cm and Scr in mg/dL where k is a constant. Ccr is corrected to 1.73 m2 body surface area. During the first year of life, the value of k is 0.33 for pre-term babies and 0.45 for term infants. The k is 0.55 for pediatric patients and adolescent girls and 0.7 for adolescent boys.

GFR (mL/min/1.73 m2) = (k x Height)/Scr

b If no loading dose administered

c The doses listed assume average body composition.

2.4 Monitoring to Assess Safety, Efficacy, and Therapeutic Blood Levels

Monitor for signs and symptoms of digoxin toxicity and clinical response. Adjust dose based on toxicity, efficacy, and blood levels.

Serum digoxin levels less than 0.5 ng/mL have been associated with diminished efficacy, while levels above 2 ng/mL have been associated with increased toxicity without increased benefit.

Interpret the serum digoxin concentration in the overall clinical context, and do not use an isolated measurement of serum digoxin concentration as the basis for increasing or decreasing the digoxin dose. Serum digoxin concentrations may be falsely elevated by endogenous digoxin-like substances [see DRUG INTERACTIONS(7.4)]. If the assay is sensitive to these substances, consider obtaining a baseline digoxin level before starting digoxin and correct post-treatment values by the reported baseline level.

Obtain serum digoxin concentrations just before the next scheduled digoxin dose or at least 6 hours after the last dose. The digoxin concentration is likely to be 10-25% lower when sampled right before the next dose (24 hours after dosing) compared to sampling 8 hours after dosing (using once-daily dosing). However, there will be only minor differences in digoxin concentrations using twice daily dosing whether sampling is done at 8 or 12 hours after a dose.

2.5 Switching from Intravenous Digoxin to Oral Digoxin

When switching from intravenous to oral digoxin formulations, make allowances for differences in bioavailability when calculating maintenance dosages (see Table 4).

Table 4. Comparison of the Systemic Availability and Equivalent Doses of Oral and Intravenous Digoxin

DOSAGE 4
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