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Biomedical subjects

K M Williamson

Publications and source records attributed to K M Williamson.

23 records · Page 2Linked to original sources
PubMedDate not supplied

Digoxin toxicity: an evaluation in current clinical practice.

BACKGROUND: Serum digoxin concentrations (SDCs) are frequently sampled before completion of drug distribution. If elevated, these concentrations may be misinterpreted, potentially leading to a misdiagnosis of digoxin toxicity. OBJECTIVES: To determine the frequency of elevated SDCs (>2.6 nmol/L [>2.0 ng/mL]) obtained at appropriate postdosing intervals and to evaluate the frequency of clinically defined digoxin toxicity in patients with elevated SDCs. METHODS: The medical records of adult patients with SDCs assayed at 5 general hospitals in North Carolina during a 3-month period (May 1 through July 31, 1996) were prospectively evaluated. Data on SDC, inpatient or outpatient status, and medical or surgical service were collected for all patients. Data on patient demographics, serum chemistry values, indication for digoxin treatment, clinical evidence of digoxin toxicity, and timing of the blood sample relative to administration of the last dose of digoxin were collected for patients with SDCs higher than 2.6 nmol/L (>2.0 ng/mL). RESULTS: Of 3434 SDCs assayed in 2009 patients, 320 (9.3%) were higher than 2.6 nmol/L (>2.0 ng/mL). Fifty-one (15.9%) of the 320 SDCs were drawn at 6 hours or less following a digoxin dose. Sampling time relative to the digoxin dose could not be determined in 70 (21.9%) of the 320 elevated SDCs, leaving 199 (62.2%) of 320 SDCs in 138 patients evaluable for digoxin toxicity. Eighty-three of the 138 patients had clinical evidence of digoxin toxicity for an overall incidence of 4.1%. CONCLUSIONS: Digoxin toxicity occurs less frequently than historically reported. Continued emphasis needs to be placed on obtaining appropriately timed SDCs.

Adult↗
PubMedDate not supplied

Is there an expanded role for digoxin in patients with heart failure and sinus rhythm? A protagonist viewpoint.

The evidence supporting the efficacy of digoxin in patients with heart failure who are in sinus rhythm is substantial. Digoxin improves hemodynamics, exercise capacity, symptoms, and quality of life and reduces hospitalizations. All of this is accomplished with a drug that is very inexpensive and can be given once daily. Its safety has been established through the DIG trial. Although digoxin does not decrease mortality beyond that of diuretics and ACE inhibitors, it does not increase mortality, unlike many positive inotropes. Furthermore, digoxin, in addition to ACE inhibitors and a diuretic, decreases the hospitalization rate due to worsening of heart failure. From a managed care perspective, as well as that of the patient, this is of enormous benefit. A pharmacoeconomic analysis estimated that continuation of digoxin in patients with stable congestive heart failure could save the healthcare system an estimated $ 400 million, based on costs from one hospital. The issue is not whether to use digoxin in these patients, but rather, how early to initiate therapy. From some of the recent data in patients with systolic dysfunction and mild heart failure, as well as knowledge of the neurohormonal activation that occurs early in these patients, it could be suggested that early use of neurohormonal modulators, including digoxin, would decrease the progression of heart failure. Thus, rather than waiting for symptoms despite optimal doses of an ACE inhibitor and diuretic, as suggested by the AHCPR practice guideline for heart failure, initiation of digoxin therapy in patients as early as NYHA class II at a dosage that will achieve a serum concentration of 1.0 ng/mL or less should occur. With the understanding of digoxin's effect on the neurohormonal systems, its role in patients with preserved systolic function needs to be reexplored. The debate can now focus on asymptomatic patients or those with preserved systolic function. Could these patients benefit from therapy with digoxin as well?

Angiotensin-Converting Enzyme Inhibitors↗
PubMedDate not supplied

Is there a role for digoxin in patients with systolic dysfunction?

In early placebo-controlled trials in patients with heart failure who were in sinus rhythm, digoxin improved hemodynamics, signs and symptoms of heart failure, and exercise capacity, and decreased functional deterioration and the need for pharmacologic cointervention. A more recent trial showed that withdrawing digoxin from patients who were clinically stable while receiving diuretics and angiotensin-converting enzyme (ACE) inhibitors often resulted in clinical deterioration, whereas continuing the agent maintained stability. Which patients should initially be treated with digoxin remains to be determined. The effects of digoxin on mortality in patients who are receiving ACE inhibitors must also be established.

Digoxin↗