5. Monitoring Pharmacotherapy In Older Adults

Front 1

Dosing

Back 1

•Adult:
–0.125mg- 0.25mg once daily
•Geriatric:
–decrease dose if decreased lean body mass (decreased Vd)
•Renal:
–CrCl 10-50 decrease dose 25-50%

Front 2

Serum Monitoring

Back 2

Half-live: 34-44 hours -> SS: 5 half-lives (7-10 days)
•Frequency
–7-10 days after initiating or changing dose
–15-20 days after dose changes in renal failure
–Every 3-6 months
•Trough concentrations
–Before next dose due
–At least 6-8 hours after last dose
–Preferably at least 12 hours after last dose
-- 2hrs post-exercise: exercise increases muscle uptake of digoxin

Front 3

Monitoring

Back 3

Therapeutic concentration
•General–0.8-2.0 ng/mL
•Heart failure–0.5-1.0 ng/mL
Lower range (0.5-0.9mg/mL) reduced mortality in CHF

Indications for testing
•Suspected toxicity
•Changing renal function
•End stage renal disease
•Electrolyte disturbances
•Interacting drugs

Front 4

SEs

Back 4

GI: Nausea, vomiting, diarrhea, anorexia
Neurologic (>serious): Fatigue, headache, delirium, confusion
Visual: Blurred or double vision, halos around lights or other images, altered color perception
Cardiac: Paroxysmal atrial tachycardia with AV block, atrial fibrillation, ventricular tachycardia, bradycardia

Additional Monitoring:
thyroid function (hyperThy decreased response, HypoThy increases)
Electrolytes (HYPOpotassium, HYPOmagnesium, and HYPERcalcium),
renal function, and EEG