Drug information of Raloxifene
Mechanism of effect
Selective estrogen receptor modulator; estrogenlike effects on bone (decreases bone resorption; increases bone density) and lipid (decrease in LDL); antiestrogenic in uterus, breast
Raloxifene, a selective estrogen receptor modulator (SERM) of the benzothiophene class, is similar to tamoxifen in that it produces estrogen-like effects on bone and lipid metabolism, while antagonizing the effects of estrogen on breast and uterine tissue. Raloxifene differs chemically and pharmacologically from naturally occuring estrogens, synthetic steroidal and nonsteroidal compounds with estrogenic activity, and antiestrogens.
Estrogens play an important role in the reproductive, skeletal, cardiovascular, and central nervous systems in women, and act principally by regulating gene expression. When estrogen binds to a ligand-binding domain of the estrogen receptor, biologic response is initiated as a result of a conformational change of the estrogen receptor, which leads to gene transcription through specific estrogen response elements of target gene promoters.
The subsequent activation or repression of the target gene is mediated through 2 distinct transactivation domains of the receptor: AF-1 and AF-2. The estrogen receptor also mediates gene transcription using different response elements and other signalling pathways. The role of estrogen as a regulator of bone mass is well established. In postmenopausal women, the progressive loss of bone mass is related to decreased ovarian function and a reduction in the level of circulation estrogens. Estrogen also has favourable effects on blood cholesterol.
Onset: 8 wk
Protein bound: >95%
Vd: 2348 L/kg
Extensively undergoes first-pass metabolism in the liver to glucuronide conjugates
Metabolites: Raloxifene-4 glucuronide, raloxifene-6 glucuronide (inactive)
Half-life: 27.7-32.5 hr
Excretion: Feces (>93%); urine (<0.2%)
Osteoporosis in Post-menopausal Women
60 mg PO qDay
Prevention; risk reduction of invasive breast cancer in postmenopausal women at high risk for invasive breast cancer
60 mg PO qDay for 5 years
Drug contraindicationspregnancy , Breast feeding
Side effectsInfection , Fever , Diarrhea , Frequent urination , nausea , chest pain , Wheeziness , asthenia , vision chang , Abdominal pain , Rhinorrhea
InteractionsTranexamic acid , Thalidomide , Lenalidomide , fluoroestradiol F 18
- Increased risk of deep vein thrombosis and pulmonary embolism has been reported with this drug
- Women with active or past history of venous thromboembolism should not take this drug
- Increased risk of death due to stroke occurred in a trial in postmenopausal women with documented coronary heart disease or at increased risk for major coronary events
- Consider risk-benefit balance in women at risk for stroke
- Discontinue 72 hours prior to and during prolonged immobilization
- Increased risk of stroke, deep vein thrombosis/pulmonary embolism
- Supplemental calcium and vitamin D recommended
- Triglyceride levels may increase in women with history of triglyceride elevation in response to oral estrogens
- Taper off estrogen treatment, then wait month before starting raloxifene
- Examine unexplained uterine bleeding
- Concurrent estrogen treatment
- Hepatic dysfunction
Points of recommendation
- Take with or without food.
- Be sure to have regular breast exams. Your doctor will tell you how often to have these. You will also need to do breast self-exams as your doctor has told you. Talk with your doctor.
- Have blood work checked as you have been told by the doctor. Talk with the doctor.
- Have a bone density test as you have been told by your doctor. Talk with your doctor.
- Limit your drinking of alcohol.
- Talk with your doctor if you will need to be still for long periods of time like long trips, bedrest after surgery, or illness. Not moving for long periods may raise your chance of blood clots.
- If you are traveling, do not stay still for long periods of time. Get up and move around as much as you can.
- This medicine works best when used with calcium/vitamin D and weight-bearing workouts like walking or PT (physical therapy).
- Follow the diet and workout plan that your doctor told you about.
- If you are taking warfarin, talk with your doctor. You may need to have your blood work checked more closely while you are taking it with this medicine.
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