A male client is diagnosed with heart failure. The health care provider orders a loading dose of digoxin. Loading doses are necessary for what reason?

Digoxin's long half-life makes therapeutic serum levels difficult to obtain without loading.

Explanation: Digoxin dosages must be interpreted with consideration of specific client characteristics, including age, weight, gender, renal function, general health state, and concurrent drug therapy. Loading doses are necessary for initiating therapy, because digoxin's long half-life makes therapeutic serum levels difficult to obtain without loading. The doses should be used cautiously in clients who have taken digoxin within the previous 2 or 3 weeks.