From the Guidelines
Individuals with Factor V Leiden mutation should avoid medications that further increase their risk of blood clots, such as combined hormonal contraceptives, hormone replacement therapy with estrogen, and certain cancer treatments that raise clotting risk. When considering medications to avoid, it's essential to look at the most recent and highest quality studies. However, based on the provided evidence from 1, we can identify several key medications and situations to avoid. These include:
- Combined hormonal contraceptives (birth control pills, patches, and rings containing estrogen)
- Hormone replacement therapy with estrogen
- Selective estrogen receptor modulators like raloxifene and tamoxifen
- Certain cancer treatments that raise clotting risk
- Tranexamic acid, used for heavy menstrual bleeding For pain management, be cautious with NSAIDs like ibuprofen and naproxen, especially with prolonged use, as they may affect platelet function 1. When surgery or immobilization is necessary, discuss thromboprophylaxis with your healthcare provider. Factor V Leiden causes resistance to activated protein C, a natural anticoagulant, making the blood more prone to clotting, as noted in the study 1. The mutation's effect varies based on whether you have one copy (heterozygous) or two copies (homozygous), with the latter carrying higher risk. Always inform all healthcare providers about your Factor V Leiden status before starting any new medication.
From the Research
Medications to Avoid with Factor V Leiden
- Oral contraceptives: Women with factor V Leiden who use oral contraceptives are at increased risk of venous thromboembolic events (VTEs) 2, 3.
- Hormone replacement therapy (HRT): HRT use in postmenopausal women with factor V Leiden may increase the risk of VTEs, with an estimated absolute incidence of 15.4 per 1000 per year 2.
- Tamoxifen: Women with breast cancer who take adjuvant tamoxifen and have factor V Leiden are at increased risk of thromboembolic events (TEs) 4.
Alternative Medications and Considerations
- Low-dose warfarin: Targeted low-dose warfarin (INR 1.5-2.0) may be a safe and effective option for long-term therapy to prevent recurrent venous thromboembolic disease in patients with factor V Leiden 5.
- Screening for factor V Leiden: Screening for factor V Leiden may be considered before instituting HRT in women with coronary disease, or before prescribing adjuvant tamoxifen to women with breast cancer, especially if a positive test would alter therapeutic decision making 2, 4, 6.