Fareston
SIDE EFFECTS
Adverse drug reactions are principally due to the antiestrogenic hormonal actions of FARESTON and typically occur at the beginning of treatment.
The incidences of the following eight clinical toxicities were prospectively assessed in the North American Study. The incidence reflects the toxicities that were considered by the investigator to be drug related or possible drug related.
| | North American Study | |
| | FAR60 n = 221 | TAM20 n = 215 |
| 35% | 30% | |
| 20% | 17% | |
| 14% | 15% | |
| 13% | 16% | |
| 9% | 7% | |
| 5% | 5% | |
| Vomiting | 4% | 2% |
| Vaginal Bleeding | 2% | 4% |
Approximately 1% of patients receiving FARESTON (n = 592) in the three controlled studies discontinued treatment as a result of adverse events (nausea and vomiting, fatigue, thrombophlebitis, depression, lethargy, anorexia, ischemic attack, arthritis, pulmonary embolism, and myocardial infarction).
Serious adverse events occurring in patients receiving FARESTON in the three major trials are listed in the table below.
| Adverse Events | North American | Eastern European | Nordic | |||
| | FAR60 n=221(%) | TAM20 n=215(%) | FAR60 n=157(%) | TAM40 n=149(%) | FAR60 n=214(%) | TAM40 n=201(%) |
| Cardiac Failure | 2 (1) | 1 (<1) | - | 1 (<1) | 2 (1) | 3 (1.5) |
| Myocardial Infarction | 2 (1) | 3 (1.5) | 1 (<1) | 2 (1) | - | 1 (<1) |
| - | - | - | - | 3 (1.5) | 1 (<1) | |
| - | - | 1 (<1) | - | 1 (<1) | 2 (1) | |
| Ocular * | ||||||
| Cataracts | 22 (10) | 16 (7.5) | - | - | - | 5 (3) |
| Dry Eyes | 20 (9) | 16 (7.5) | - | - | - | - |
| Abnorma Visual Fields | 8 (4) | 10 (5) | - | - | - | 1 (<1) |
| Corneal Keratopathy | 4 (2) | 2 (1) | - | - | - | - |
| 3 (1.5) | 2 (1) | 1 (<1) | - | - | 1 (<1) | |
| Abnormal Vision/Diplopia | - | - | - | - | 3 (1.5) | - |
| Thromboembolic | ||||||
| 4 (2) | 2 (1) | 1 (<1) | - | - | 1 (<1) | |
| Thrombophlebitis | - | 2 (1) | 1 (<1) | 1 (<1) | 4 (2) | 3 (1.5) |
| - | 1 (<1) | 1 (<1) | - | 3 (1.5) | 4 (2) | |
| CVA/TIA | 1 (<1) | - | - | 1 (<1) | 4 (2) | 4 (2) |
| Elevated Liver Tests ** | ||||||
| 11 (5) | 4 (2) | 30 (19) | 22 (15) | 32 (15) | 35 (17) | |
| 41 (19) | 24 (11) | 16 (10) | 13 (9) | 18 (8) | 31 (15) | |
| 3 (1.5) | 4 (2) | 2 (1) | 1 (<1) | 2 (1) | 3 (1.5) | |
| 6 (3) | 6 (3) | 1 (<1) | - | - | - | |
| * Most of the ocular abnormalities were observed in the North American Study in which on-study and biannual ophthalmic examinations were performed. No cases of retinopathy were observed in any arm. | ||||||
| ** Elevated defined as follows: North American Study: SGOT >100 IU/L; alkaline phosphatase >200 IU/L; bilirubin >2 mg/dL. Eastern European and Nordic studies: SGOT, alkaline phosphatase, and bilirubin - WHO Grade 1 (1.25 times the upper limit of normal). | ||||||
Other adverse events of unclear causal relationship to FARESTON included leukopenia and thrombocytopenia, skin discoloration or dermatitis, constipation, dyspnea, paresis, tremor, vertigo, pruritis, anorexia, reversible corneal opacity (corneal verticulata), asthenia, alopecia, depression, jaundice, and rigors.
In the 200 and 240 mg FARESTON dose arms, the incidence of SGOT elevation and nausea was higher. Approximately 4% of patients were withdrawn for toxicity from the high-dose FARESTON treatment arms. Reasons for withdrawal included hypercalcemia, abnormal liver function tests, and one case of toxic hepatitis, depression, dizziness, incoordination, ataxia, blurry vision, diffuse dermatitis, and a constellation of symptoms consisting of nausea, sweating, and tremor.
DRUG INTERACTIONS
Drugs that decrease renal calcium excretion, eg, thiazide diuretics, may increase the risk of hypercalcemia in patients receiving FARESTON. There is a known interaction between antiestrogenic compounds of the triphenylethylene derivative class and coumarin-type anticoagulants (eg, warfarin), leading to an increased prothrombin time. When concomitant use of anticoagulants with FARESTON is necessary, careful monitoring of the prothrombin time is recommended.
Cytochrome P450 3A4 enzyme inducers, such as phenobarbital, phenytoin, and carbamazepine increase the rate of toremifene metabolism, lowering the steady-state concentration in serum. Metabolism of toremifene may be inhibited by drugs known to inhibit the CYP3A4-6 enzymes. Examples of such drugs are ketoconazole and similar antimycotics as well as erythromycin and similar macrolides. This interaction has not been studied and its clinical relevance is uncertain.
Generic Name: Toremifene
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