Transcript Slide 1

Response to An Initial Dose of Warfarin in Thai
Patients Undergoing Long-Term Anticoagulant
Therapy
Weerayuth Saelim R.Ph.
2nd year Pharmacy resident
The college of pharmacotherapy of Thailand
Researchers:
Pornwalai Boonmuang1, Wichai Santimaleeworagun1, Daraporn Rungprai1, Juthathip Suphanklang1,
Piyarat Pimsi1,Ornanong Hongchumpae2, Wandee Sumret2, Sakonwan Pounghom2,
Ornsucha Kriangsuwan2
1
1Department
2Department
of Pharmacy, Faculty of Pharmacy, Silpakorn University
of Pharmacy, Hua Hin Hospital
Introduction
 Warfarin is the narrow therapeutic medications.
 Accomplish a goal of therapeutic international normalized
ratio (INR) with warfarin treatment as soon as possible is
important because of the benefit in thromboembolism risk
reduction.
2
Objectives
• This study aimed to describe
– The efficacy and safety of initial dosing of
warfarin in Thai patients.
3
Methodology
4
Methods
 A retrospective study was conducted at
Warfarin clinic, Hua Hin Hospital, Thailand.
5
Warfarin clinic in Hua-Hin Hospital
6
Methods
 Inclusion criteria
 Patients who were at least 18 years old .
 Who were initiated warfarin therapy from June 2012 to June
2014 were evaluated.
 Initial dose of warfarin was adjusted by the physicians.
 The patients who had 2 follow up visits consecutively.
7
Methods
 Exclusion criteria
 The patients who had longer than 12 weeks apart.
 The patients who did not have an INR values.
8
Methods
The data were collected
 Patient demographic data
 Warfarin dosing
 INR values
 Duration for follow up
 Drug interactions
 Bleeding or thrombosis events
9
Methods
• Primary endpoint
– The target INR of 2.0-3.0 (eg. atrial fibrillation,
Left ventricular thrombus (LA), Left atrium thrombus(LA))
– The target INR of 2.5-3.5 for mechanical valve
replacement.
• Secondary endpoints.
– Bleeding complication
– Subtherapeutic or supratherapeutic INR values
10
Results
11
Patient characteristics
Patient characteristics
Male (%)
Total (n = 55)
28 (50.9)
Mean age, year (±SD)
Range, year
61.3 (± 13.8)
22.0-85.0
Body weight , Kg (±SD)
Range, Kg
61.5 (±12.2)
41.0-95.0
Mean initial dose of warfarin, mg (± SD)
Range, mg
2.5 (± 0.6)
1.0-3.0
Mean duration for follow up ,day (±SD)
Range, day
23.3 (±14.0)
7.0-70.0
12
Indication for warfarin therapy
LV/LA
Deep vein
thrombus
thrombosis
Pulmonary
4%
2%
embolism
7%
Mechanical valve
replacement
16%
Atrial
fibrillation
71%
LV: Left ventricular , LA: Left atrium
13
Underlining disease (%)
Underlining disease (%)
70.0
61.8
60.0
43.6
50.0
36.4
40.0
34.5
30.0
18.2
20.0
10.0
0.0
5.5
9.1
9.1
3.6
disease
14
Efficacy
15
Patient who achieved target INR (%)
23.6%
76.4%
Appropriated INR
Inappropriated INR
16
Patient who had out of target INR (%)
12.7%
23.6
%
63.6%
Subtherapeutic INR
76.4
%
Appropriated INR
Inappropriated INR
Supratherpeutic target INR
17
Compare dose of warfarin to
achieved target INR
Pearson chi-square test
Dose of warfarin
(mg)
Achieved target
INR
Not Achieved
target INR
Total
<3
3
Total
4
9
13
21
21
42
25
30
55
p-value = 0.224
18
Safety
19
Thrombosis and bleeding events (%)
Thrombosis and
bleeding events (%)
5.5
6
5
4
3
2
1
0
0
Events
0
Thrombosis
event
Major bleeding
Minor Bleeding
20
Discussions
21
Discussions
• Limitation of the study
– Less subjects did not show the significant
different between dose of warfarin
– However,
in
this
study
had
the
same
of
percentage of patients who achieved target INR in
the study of Bundarika et al. at Siriraj Hospial
(about 30%)
22
J Med Assoc Thai 2011; 94 (Suppl. 1):S225-S231
Conclusion
 Although recent evidence suggested that an initial
dose of warfarin use as <3 or 3 mg might be
relatively less effective.
 The clinicians should consider patient specific
factors prior to making a decision for an initial
warfarin dose.
23
Thank you for your attentions
24