Elliot is a 74 year-old male who presents to your clinic
with complaints of frequent nosebleeds (4 in the past week) and several severe
bruises scattered variously throughout his anatomy. The patient is also
complaining of a runny nose, cough, and head/chest congestion. He has a history
of chronic atrial fibrillation and is currently prescribed and taking warfarin.
Approximately 3 weeks previously, he started taking over-the-counter cimetidine
for heartburn he was experiencing. Below
is a list of the patient’s medications, his physical examination, and his
laboratory findings:

Medications

Digoxin 0.25 mg QD

Cimetidine OTC BID

Pseudoephedrine SR 120 BID

Warfarin 7 mg QD

Allergies: NKDA

Physical Examination

VS: BP: 180/95, HR 75, irregularly irregular, RR 17

Weight: 95 kg

HEENT: WNL

ABD: + Bowel Sounds

EXT: Bruising on arms and legs

NEURO: Alert & Oriented x 3

GEN: Well developed, well-nourished male

ECG: atrial fibrillation

Laboratory

Na 143 mEq/L

K 4.5 mEq/L

Cl 99 mmol/L

CO2 25 mEq/L

BUN 18 mg/dL

SCr 0.9 mg/dL

INR 4.8

Hct 42%

Hbg 15 mg/dL

Digoxin 3.8 ng/ml