Anticoagulation and Psychotropic Medications

Bachawati, Maurice

doi:10.1007/s11920-010-0120-z

“…Warfarin is composed of two racemic active forms, R-enantiomers and S-enantiomers, serum depletion and metabolism of which largely depends on hepatic enzymes [ 9 , 10 ]. R-isomers are 2–5 times less potent than their S-isomer counterparts [ 11 ].…”

Section: Discussionmentioning

confidence: 99%

The critical interaction between valproate sodium and warfarin: case report and review

Zhou

¹

,

Sui

²

,

Zhao

³

et al. 2018

BMC Pharmacol Toxicol

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BackgroundValproic acid (VPA) and warfarin are commonly prescribed for patients with epilepsy and concomitant atrial fibrillation (AF). When VPA and warfarin are prescribed together, clinically important interactions may occur. VPA may replace warfarin from the protein binding sites and result in an abnormally increased anticoagulation effect. This is commonly underrecognized.Case presentationIn our case, we report a 78-year-old woman with a glioma who presented with status epilepticus. The patient was on warfarin to prevent cardiogenic embolism secondary to AF. Intravenous loading dose of VPA was administered, but international normalized ratio (INR) increased significantly to 8.26. Intravenous vitamin K1 was then given and the patient developed no overt bleeding during the hospitalization.ConclusionBy reviewing the literature and discussing the critical interaction between valproate sodium and warfarin, we conclude that intravenous VPA and the co-administrated warfarin may develop critical but underrecognized complications due to effects on the function of hepatic enzymes and displacement of protein binding sites.

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“…The use of psychotropics in the management of mental illness is becoming increasingly prevalent as the literature on their efficacy expands. As with the general population, patients with mental illness are at risk of developing thromboemboli, including deep vein thromboses, pulmonary emboli, and thromboembolic complications of atrial fibrillation or cardiac valve replacement . Despite the risks associated with its use, warfarin is used for the prophylaxis and treatment of thromboemboli in the outpatient setting.…”

Section: Outlinementioning

confidence: 99%

Drug‐Drug Interactions Between Warfarin and Psychotropics: Updated Review of the Literature

Nadkarni

¹

,

Oldham

²

,

Howard

³

et al. 2012

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As the number of psychotropics on the market expands, the likelihood increases that a patient requiring anticoagulation with warfarin will receive concurrent treatment with a psychotropic drug. Because warfarin undergoes hepatic metabolism and is highly protein bound, it is particularly prone to drug interactions; in addition, its relatively narrow therapeutic window places patients at risk of either hemorrhagic or thrombotic complications. Although warfarin's interactions with other drugs have long been studied, the most recent review of the literature of warfarin's interactions with psychotropics was over a decade ago. Thus, we conducted a systematic review of the literature documenting the interaction between warfarin and psychotropics, with a focus on interactions mediated through the cytochrome P450 system and protein binding. A search of the MEDLINE database was performed, and reports of warfarin interactions with psychotropics were identified. The results suggest that interactions between warfarin and psychotropic drugs are important and likely underrecognized. They also have notable implications for both safety and drug compliance. When certain psychotropics are started or discontinued in patients receiving warfarin therapy, or when warfarin is introduced to a patient receiving a stable dose of a psychotropic, clinicians should monitor a patient's international normalized ratio (INR) closely to ensure it remains within therapeutic range. Psychotropics that pose a particular risk of increasing the INR when used with warfarin include fluoxetine, fluvoxamine, quetiapine, and valproic acid. Psychotropics that may significantly decrease the INR when used with warfarin include trazodone, St. John's wort, carbamazepine, and the polycyclic aromatic carbons in tobacco cigarettes; however, nicotine itself, as in nicotine replacement strategies, is not known to alter warfarin's anticoagulant effect. In certain cases, the need for anticoagulation may also necessitate switching to a different psychotropic.

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“…The S-enantiomer is metabolized primarily by the CYP2C9 isoenzyme, whereas the R-enantiomer is metabolized primarily by the CYP1A2 isoenzyme and through minor pathways by the CYP2C19 and CYP3A4 isoenzymes. 2 Interactions between warfarin and psychotropics mediated by the CYP system are of significant clinical concern given warfarin's narrow therapeutic window. Protein displacement has also been considered as a potential means of interaction, 8 particularly given that warfarin is more than 95% protein bound at therapeutic concentrations.…”

Section: Cytochrome P450 System and Protein Bindingmentioning

confidence: 99%

“…As with the general population, patients with mental illness are at risk of developing thromboemboli, 1 including deep vein thromboses, pulmonary emboli, and thromboembolic complications of atrial fibrillation or cardiac valve replacement. 2,3 Despite the risks associated with its use, warfarin is used for the prophylaxis and treatment of thromboemboli in the outpatient setting. However, interactions between warfarin and psychotropics are myriad.…”

mentioning

confidence: 99%

“…Subtherapeutic or supratherapeutic values can result in increased risk for thromboemboli or hemorrhagic complications, respectively. [2][3][4][5] Clinicians should be wary of interactions when introducing agents that may affect warfarin metabolism (e.g., valproic acid) as well as when discontinuing certain agents (e.g., carbamazepine). In general, the time to expected onset and reversal of the competitive inhibition of cytochrome P450 (CYP) enzymes is related to the half-life of the competitive agent.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Drug-Drug Interactions Between Warfarin and Psychotropics: Updated Review of the Literature

Nadkarni

¹

,

Oldham

²

,

Howard

³

et al. 2012

View full text Add to dashboard Cite

As the number of psychotropics on the market expands, the likelihood increases that a patient requiring anticoagulation with warfarin will receive concurrent treatment with a psychotropic drug. Because warfarin undergoes hepatic metabolism and is highly protein bound, it is particularly prone to drug interactions; in addition, its relatively narrow therapeutic window places patients at risk of either hemorrhagic or thrombotic complications. Although warfarin's interactions with other drugs have long been studied, the most recent review of the literature of warfarin's interactions with psychotropics was over a decade ago. Thus, we conducted a systematic review of the literature documenting the interaction between warfarin and psychotropics, with a focus on interactions mediated through the cytochrome P450 system and protein binding. A search of the MEDLINE database was performed, and reports of warfarin interactions with psychotropics were identified. The results suggest that interactions between warfarin and psychotropic drugs are important and likely underrecognized. They also have notable implications for both safety and drug compliance. When certain psychotropics are started or discontinued in patients receiving warfarin therapy, or when warfarin is introduced to a patient receiving a stable dose of a psychotropic, clinicians should monitor a patient's international normalized ratio (INR) closely to ensure it remains within therapeutic range. Psychotropics that pose a particular risk of increasing the INR when used with warfarin include fluoxetine, fluvoxamine, quetiapine, and valproic acid. Psychotropics that may significantly decrease the INR when used with warfarin include trazodone, St. John's wort, carbamazepine, and the polycyclic aromatic carbons in tobacco cigarettes; however, nicotine itself, as in nicotine replacement strategies, is not known to alter warfarin's anticoagulant effect. In certain cases, the need for anticoagulation may also necessitate switching to a different psychotropic.

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Anticoagulation and Psychotropic Medications

Cited by 6 publications

References 48 publications

The critical interaction between valproate sodium and warfarin: case report and review

The critical interaction between valproate sodium and warfarin: case report and review

Drug‐Drug Interactions Between Warfarin and Psychotropics: Updated Review of the Literature

Drug-Drug Interactions Between Warfarin and Psychotropics: Updated Review of the Literature

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