Therapeutic drug monitoring of digoxin: Help or hindrance?
- 60 Downloads
A major role of therapeutic drug monitoring services is to advise on the dose of a drug which would be required to bring the concentration in the blood to within specific ‘therapeutic’ limits. Monitoring digoxin usage constitutes a substantial part of the work load.
We have examined the potential variability in recommendations for digoxin dosages based on a series of serum digoxin measurements in each of 80 out-patients.
In over a third of cases a dose, which seemed to be optimal on the basis of the first assay result, would have produced concentrations outside the conventional therapeutic range when the measurement was repeated. This was despite careful supervision of medication and the timing of the blood sample in relation to its administration. In routine practice the apparent variability in dose requirements would be far greater.
Objectives of therapeutic drug monitoring services remain the same, the way forward would seem to lie in their taking on a heavy commitment to counsel and supervise patients before repeated blood sampling. However, effort and resources might be better channelled into producing simple prescribing aids relating the risk of cardiotoxicity directly to the size of the maintenance dose and the individual's renal function.
Key wordsdigoxin therapeutic drug monitoring
Unable to display preview. Download preview PDF.
- Beller GA, Smith TW, Abelmann WH, Haber E, Hood WB (1971) Digitalis intoxication, a prospective clinical study with serum level correlations. N Engl J Med 284: 989–997Google Scholar
- Council statement (1985) Guidelines for a pharmacy-based pharmacokinetic serivce. Pharm J 234: 626–627Google Scholar
- Dobbs SM, Parkes J, Rodgers EM (1976) Digoxin: linearity between dose and concentration. Br J Clin Pharmacol 3: 940–941Google Scholar
- Dobbs SM, Rodgers EM, Kenyon WI, Livshin D, Slater E, Godsmark B (1977) Digoxin prescribing in perspective. Br J Clin Pharmcol 4: 327–335Google Scholar
- Dobbs RJ, Nicholson PW, Dobbs SM (1983) Prediction of digoxin dose requirements. In: Avery G (ed) Topics in clinical pharmacokinetics. ADIS Press, SydneyGoogle Scholar
- Ingelfinger JA, Goldman P (1976) The serum digitalis concentration — does it diagnose digitalis toxicity? N Engl J Med 294: 867–870Google Scholar
- Jenkins T, Deshmukh AA, Dobbs RJ (1985) Distribution of maintenance doses of digoxin required to produce therapeutic serum concentrations in elderly patients. J Pharm Pharmacol 37 (Suppl): 157 PGoogle Scholar
- Jogestrand T, Norlander R (1983) Serum digoxin determination in outpatients — need for standardisation. Br J Clin Pharmacol 15: 55–58Google Scholar
- Johnson BF, Bye C (1975) Maximal intestinal absorption of digoxin and its relation to steady state plasma concentration. Br Heart J 37: 203–208Google Scholar
- Koch-Weser J, Duhme DW, Greenblatt DJ (1974) Influence of serum digoxin concentration measurements on frequency of digitoxicity. Clin Pharmacol Ther 16: 284–287Google Scholar
- Nicholson PW, Dobbs SM, McGill APJ, Rodgers EM, Slater E (1978) A score for prescribing digoxin. Br Heart J 40: 467–470Google Scholar
- Nicholson PW, Dobbs SM, Rodgers EM (1980) Ideal sampling time for digoxin assays. Br J Clin Pharmacol 9: 467–470Google Scholar
- Ogilvie RI, Ruedy J (1972) An educational program in digitalis therapy. J Am Med Assoc 222: 50–55Google Scholar
- Pearce P, Deshmukh AA, Dobbs SM (1985) Ototoxicity of gentamicin in the elderly. J Pharm Pharmacol 37 (Suppl): 158 PGoogle Scholar
- Sheiner LB (1980) Intelligent use of drug blood level data is helpful in managing patients. In: Controversies in therapeutics. WB Saunders, Philadelphia, pp 100–105Google Scholar
- Siersbaek-Nielsen K, Hansen JM, Kampmann U, Kristensen M (1971) Rapid evaluation of creatinine clearance. Lancet 2: 1133–1134Google Scholar
- Turner J, Dobbs SM, Nicholson PW, McGill APJ, Rodgers EM, Parkes J (1977) Influence of diet on digoxin dose requirements. Br J Clin Pharmacol 4: 489–491Google Scholar