Graves’ Disease and Treatment Effects on Warfarin Anticoagulation

Table 3

Outpatient warfarin response status after radioactive iodine ablation of the thyroid and discontinuation of methimazole.

Days since ablation	Warfarin dose^a; (mg/day)	INR^b,c	New warfarin^a dose; (mg/day)	TSH^d; (𝜇IU/mL)	Free T4^e; (ng/dL)	Free T3^f; (pg/mL)
7	5: TWRSSu; 7.5: MF	1.6	5: TRSSu; 7.5: MWF
14	5: TThSSu; 7.5: MWF	3.1	5: TWThSSu; 7.5: MF
24	5: TWThSSu; 7.5: MF	2.9	No change
42	5: TWThSSu; 7.5: MF	3.3	5: MTWThSSu; 7.5: F		1.78	4
67	5: MTWThSSu; 7.5: F	2.8	No change
94	5: MTWThSSu; 7.5: F	2.7	No change	0.163	0.45
122	5: MTWThSSu; 7.5: F	2.5	No change

aLetters are abbreviations for days of the week: Monday (M), Tuesday (T), Wednesday (W), Thursday (R), Friday (F), Saturday (S), and Sunday (Su).
^bINR: international normalized ratio, goals 2-3.
^cINR obtained via point of care testing with Roche Diagnostics CoaguChek XS.
^dTSH: thyroid stimulating hormone, reference range 0.450–4.500.
^eFree T₄: free thyroxine, reference range 0.82–1.77.
^fFree T₃: free triiodothyronine, reference range 2–4.4.