Calculate the oral loading dose for a 70 yo, 70 kg adult male with a serum creatinine of 3. Recommended dosages of digoxin may require considerable modification because of individual sensitivity of the patient to the drug, the presence of associated conditions, or the use of concurrent medications. Gareth malson updated with approvals from wirral drug and therapeutics committee. Digoxin is specifically indicated where cardiac failure is accompanied by atrial fibrillation.
For a woman with a lean body weight of 50 kg this would work out at a total dose of 15 x 50 750 micrograms. Digoxin is a cardiac glycoside that can be used in patients with both atrial. A steady state will be achieved after five cycles of the drug halflife t12. Digoxin is approximately 7080% absorbed in the first part of the small bowel. A178252 tmax, or the time to reach the maximum concentration of digoxin was measured to be 1. Drug information table cardiac glycosides digoxin lanoxin therapeutic use administration maintenance therapy for heart failure treats some cardiac dysrhythmias atrial fibrillation atrial flutter paroxysmal atrial tachycardia available as oral tablets, capsules, and elixir, as well as for iv use. Evaluate patient carefully to determine the appropriate dose. Digoxin loading dose guide adults digoxin is indicated in the management of chronic cardiac failure.
About 70 to 80% of an oral dose of digoxin is absorbed, mainly in the proximal part of the small intestine. Consider patientspecific characteristics leanideal body weight, crc l, age, concomitant disease states, comcomitant medications, drug ser um level, and factors likely to alter pharmacokinetics when dosing tablets can be crushed and administered with food or fluids use a calibrated measuring device for liquid preparations. A simple explanatory table was developed indicating the loading dose administered according to fg and recommended times for pharmacokinetic monitoring and the second dose. The remaining onefourth loading dose given after an additional 8 to 12 hours iv or po 4. Digoxin blood levels are used for adjusting doses in order to avoid toxicity. Digoxin tablets bp 250 micrograms summary of product. This loading dose worksheet is intended to guide medical, nursing and pharmacy staff in the safe and appropriate prescription and administration of oral digoxin loading doses in. Evaluation of digoxin concentration after loading dose in. Loading dose use syringe driver amiodarone 300mg made up to 50mls with 5% glucose infuse over 30 minutes 4. In selecting a dose of digoxin, the following factors must be considered. Printed copies are not controlled and may not be the current version in use. Acls drugs, cardioversion, defibrillation and pacing.
Dosage guidelines provided are based upon average patient response and. The degree of binding to serum albumin is 20 to 30%. They were then used to evaluate the appropriateness of random samples of inpatient and outpatient serum digoxin levels. Approximately 90% adult patients with proven digoxin toxicity have serum digoxin levels greater than 2. Iv maintenance dose % daily loss x total body stores 0. Purpose the development of a protocol of digoxin impregnation was proposed. If the patient appears to develop toxicity or is therapeutically controlled, the remainder of the calculated loading dose is withheld. When lanoxin tablets are taken after meals, the rate of absorption 50 is slowed, but the total amount of digoxin absorbed is usually unchanged. Total loading dose pma weeks iv mcgkg po mcgkg 29 15 20 30 to 36 20 25 37 to 48 30 40 49 40 50 divide into 3 doses over 24 hours. Acls drugs, cardioversion, defibrillation and pacing ace inhibitors angiotensinconverting enzyme inhibitors enalapril. A178228 the bioavailability of an oral dose varies from 5090%, however, oral gelatinized capsules of digoxin are reported to have a bioavailability of 100%.
It is also used to treat a certain type of irregular heartbeat chronic atrial fibrillation. The loading dose of digoxin should be reduced in patients who are also receiving disopyramide. Guidelines for use of digoxin lanoxin recommended neonatal dose, route, and interval loading or digitalizing dose. Guidelines are for adult patients unless otherwise stated.
Pdf digoxin dosage in patients with gastric hyperacidity. Absorption of digoxin from lanoxin tablets has been 48 demonstrated to be 60% to 80% complete compared to an identical intravenous dose of digoxin 49 absolute bioavailability. Calculate the cp if a 70 yo, 70 kg man with a serum creatinine of 3. Maintenance cl cp t dose f cp f dose t cl cl equations for digoxin. In approximately 10% of patients, a small portion of a digoxin dose is metabolized in the gut by intestinal eubacterium lentum, an anaerobic bacillus, to inactive digoxin reduction products drps.
Continuous infusion use syringe driver amiodarone 450mg made up to 50mls with 5% glucose infuse at 4. The estimated risk among new users was higher than among patients already using digoxin, which is consistent with a drug that increases early mortality. In general, doses required for atrial arrhythmias are. Treating an irregular heartbeat can decrease the risk for blood clots, an effect that may reduce your risk.
Guide for drug level monitoring of commonly used medications. Digoxin oral tablet is available as the brandname drug lanoxin. Digoxin digoxin dose, indications, adverse effects. Digoxin and mortality in patients with atrial fibrillation. Obtain serum digoxin concentrations just before the next scheduled digoxin tablets dose or at least 6 hours after the last dose. For rapid effect, a larger initial loadingdigitalizing dose should be given in several divided doses over 1224 hr. Clinical pharmacokineticsdigoxin at the end of the. Policy for the use of digoxin specific antibody digifab. Maintenance doses are determined for digoxin by renal function. Divided doses as above assess for clinical response and consider withholding 16 hour dose if responds. It is also used for atrial fibrillation to reduce the ventricular rate. The therapeutic benefit of digoxin is greater in patients with ventricular dilatation.
A loading dose should be given of 15 microgramskg of lean body weight. Onefourth the loading dose given 8 to 12 hours later iv or po 3. High concentrations are found in the heart and kidneys, but the skeletal muscles form the largest digoxin storage. Digoxin gloucestershire hospitals nhs foundation trust. Po maintenance dose iv maintenance dose divided by 0. Obtain ecg 6 hours after digitalizing dose to assess for toxicity. Digoxin can be used to treat heart failure when symptoms remain despite the use of other drugs. Acute setting for patients with hf and without accessory pathway. As per accfaha guidelines, a loading dose to initiate digoxin therapy in patients with heart failure is not necessary.
The doses of digoxin used in controlled trials in patients with heart failure have ranged from 125 to 500 mcg 0. The digoxin concentration is likely to be 10 to 25% lower when sampled right before the next dose 24 hours after dosing compared to sampling 8 hours after dosing using oncedaily dosing. All dosing must be evaluated by individual response. Loading and maintenance doses are 75% of oral dose. The dogs were given an intravenous loading dose of digoxin 25 gkg on day 1 and then dosed orally each morning thereafter using lanoxin syrup 14 gkg of digoxin. Therapeutic drug monitoring medicines formulary, version 7 principal author. Evaluating the appropriateness of digoxin level monitoring. Background digoxin level determinations can be useful clinically in patients receiving digoxin therapy but are sometimes misused methods explicit appropriateness criteria were adapted from previously published criteria and revised using local expert opinion. In these studies, the digoxin dose has been generally titrated according to the patients age, lean body weight, and renal function.
Reduce digoxin concentrations by decreasing the digoxin dose by approximately 30 to 50% or by modifying the dosing frequency, and continue monitoring. Drug guideline digoxin nsw agency for clinical innovation. Pkp008 implementation of a monitoring protocol for digoxin. Administer onehalf the total loading dose initially all formulations, then give onefourth the total loading dose every 6 to 8 hours for two doses iv and tablets, or give additional fractions every 4 to 8 hours oral solution. After intravenous digoxin, sixday urinary recovery averaged 76 per cent of the dose. Materials and methods experimental protocol six greyhound dogs weighing 22. There was a marked and early increase in sudden death among new digoxin users with. Loading dosing regimen in adults and pediatric patients.
Digoxin is used to treat heart failure, usually along with other medications. Slow digoxin loading slow oral digitalization, generally preferred for most patients, can be achieved by starting a maintenance dose of 0. Digoxin metabolism in patients jama internal medicine. This is likely to be clinically significant only in patients with high plasma levels of digoxin or those with atrioventricular nodal dysfunction. This loading dose worksheet is intended to guide medical, nursing and pharmacy staff in the safe and appropriate prescription and administration of oral digoxin loading doses in adults 2. Digoxin is extensively distributed in the tissues, as reflected by the large volume of distribution. Digoxin how to load digoxin loading dose iv digoxin loading dose iv. In 100 patients receiving digoxin to control heart disease, metabolic reduction of the lactone ring of digoxin was investigated. For patients with af and atrial flutter, digoxin works best when a high dose is given as an initial loading dose rapid digitalisation.