Siriraj Medical Journal

69-72

Authors: Angsu Chartrungsan, M.D., Pansak Laksanabunsong, M.D., Akarin Nimmannit, M.D.**, Bundarika Suwanawiboon, M.D.***, Naravat Poungvarin, M.D.****, Wanchai Wongkornrat, M.D.*, Kriangkrai Tantiwongkosri, M.D., Worawong Slisatkorn, M.D., Pranya Sakiyalak, M.D., Punnarerk Thongcharoen, M.D., Thaworn Subtaweesin, M.D., Somchai Sriyoschati, M.D., Teeravit Phanchaipetch, M.D.

Objective: The ACCP guideline 2008 recommended cessation of warfarin ve days before surgery. However, based on the observation of the clinical practice at Siriraj Hospital, we suggested a shorter period of three days before surgery. Prior studies have shown multiple factors had effected warfarin dosage, but few studies have shown factors that in uenced normalization of prothrombin time after discontinuation of warfarin. Previous studies have shown the genetics factors, vitamin K epoxide reductase (VKORC1) and cytochrome P450 2C9 (CYP2C9) enzyme conjointly determine the warfarin maintenance dose. We wanted to nd out the proper timing of warfarin cessation before surgery and relationhip to genetic factors. Methods: Sixty-eight patients on warfarin were randomized to stop warfarin for three or ve days. Blood samples were acquired at three or ve days after interruption of warfarin in each group and assayed for INR, VKORC1 and CYP2C9. We started bridging therapy when INR was less than 2.0 and accepted an INR value of 1.5 or less on the day of surgery. Results: A total of 68 patients were enrolled in the study. Thirty-three patients (48.5%) were male. The mean age was 50.8 ± 6.6 years (range 16-88 years). The mean BMI was 22.5 ± 3.6 kg. All patients had mechanical heart valve replacement, and 22 (32.4%) patients had AF. The mean cumulative weekly dose of warfarin was 27 ± 11.3 mg and baseline INR was 2.4 ± 0.3. Thirty (88.2%) patients in the three days group had INR ≤ 1.5 and thirty-three (97.3%) patients in the ve days group had INR ≤ 1.5. There was no signi cant difference between interruption of warfarin for three and ve days (p =0.16). Female sex, BMI and weekly warfarin dosage were associated to the longer cessation of warfarin. Only weekly warfarin dosage was a signi cant factor after multivariate analysis. From 68 patients, CYP2C9 *1/*1 was found in 93% and CYP2C9 *1/*3 was found in 7%. Neither mutant CYP2C9*2 allele nor individuals homozygous for CYP2C9*3 were observed. Regarding VKORC1, haplotype AB was found in 32% and haplotype AA was found in 63%. Haplotype BB (wild type) was found in 4%. Five patients who had INR > 1.5 after interruption of warfarin had VKORC1 haplotype AA, four patients had CYP2C9*1/*1 and one patient had CYP2C9 *1/*3. Neither VKORC1 nor CYP2C9 was related to normalization of INR (p=0.10, p=0.17). Conclusion: Temporary interruption of the warfarin therapy between three days and ve days with bridging therapy before surgery is not signi cantly different in the Thai population. This study recommends discontinuing warfarin three days before surgery. The proper timing of interruption for warfarin does not only depend on the half-life of warfarin but also depends on age, co morbidity, sex, BMI, lower maintenance warfarin dose, and concomitant drugs. If patients have cardiac or liver disease, they may spend longer time to discontinue warfarin before surgery.Warfarin, interruption, surgery, anticoagulant, cessation

77-80

Authors: Tanita Thaweethamcharoen, Ph.D.*, Prapaporn Noparatayaporn, B.Sc.Pharm., Cherdchai Nopmaneejumruslers, M.D., Thitinan Bunrod, B.Sc.Pharm.*

Objective: To study drug expenditure and the pattern of Non-Essential drug (NED) use after the restriction policy at a large University Hospital in Thailand. Methods: The computerized data of the large University Hospital in Thailand was analyzed using a ‘I control chart’ with a statistically process-controlled method for the three highest oral drug expenditure groups of the hospital which included statins, proton pump inhibitor (PPIs), and non steroidal anti-in ammatory drugs (NSAIDs). The data of prior periods were collected before (December 2009-November 2010) and after (January 2011-August 2012) the implementation of the restricted policy of NED reimbursement was launched in December 2010. Results: Both statins and PPIs expenditure were decreased more than 30% while NSAIDs was decreased about 25% after implementation of the policy. Drug expenditure cost was decreased about 177 million Baht per year in the three groups. The patterns of drug usage were changed from NED to Essential drug (ED) about 36%, 26% and 7% in statins, PPIs and NSAIDs groups, respectively. Conclusion: The restriction of the NED prescribed policy was able to reduce the drug expenditure of the large university hospital. However the sustainable cost saving must be followed for the long term period.

85-87

Authors: Alok Saxena, M.Sc., Sachin Soni, M.S., Tuhin Ghulyani, MS., Amal Rani Das, MS.

Variations are important ndings for anatomists, radiologists and surgeons. Variations may be either skeletal or neurovascular. It may simulate the normal/abnormal (malignant) structures and misguide the radiologists and surgeons during diagnostic and surgical procedures. Hence, it becomes essential to disseminate the knowledge of variations. Keeping this in mind, we report a case of a third head of gastrocnemius in a male cadaver. This muscle was observed in the right popliteal fossa, arising from lateral condyle of femur and merging with two heads of gastrocnemius.