What side effects can tamoxifen have?
Below you will find the most important information about possible known side effects of tamoxifen.
These side effects do not occur, but you can. Because every person reacts differently to medication. Please also note that the type and frequency of side effects may vary depending on the drug formulation (eg tablet, syringe, ointment).
Very Common Side Effects:
Hot flashes, Cycle changes, Menstrual suppression, Outflow.
Common side effects:
Anemia (temporary), drowsiness, headache, blurred vision (only partially transient, cataracts and / or retinal damage), nausea, rash, hair loss, body fluid congestion, lipid metabolism disorder (blood triglyceride Value increase), circulatory disorders in the brain, calf cramps, blood vessel obstruction (including deep-seated veins and pulmonary embolisms), bone pain (at the beginning of therapy), pain at the tumor site, vaginal itching, vaginal bleeding, myoma enlargement, new tissue formation on the endometrium (including endometriosis and endometrial polyps) .
Uncommon side effects:
Hemorrhagic disorders (neutrophil deficiency, white blood cell deficiency, transient platelet deficiency), vomiting, hypersensitivity reactions (including laryngeal swelling), excess blood calcium (in patients with bone metastases, especially at baseline), stroke , Liver-enzyme-mutation, uterine cancer.
Rare side effects:
Optic nerve damage, optic nerve inflammation, fatty liver, biliary congestion, hepatitis, jaundice, ovarian cyst, uterine cancer.
Very rare side effects:
neutrophil deficiency (severe), all blood cell deficiency, blindness, pneumonia, erythema multiforme, Stevens-Johnson syndrome, skin blister disease (bullous pemphigus), severe blood triglyceride excess (in part thereby pancreatitis).
Side effects of unknown frequency:
absence of granulocytes, skin blood vessel inflammation.
The risk for the development of cataract increases with the duration of tamoxifen intake.
The incidence of blockage of the veins is especially increased with concomitant chemotherapy.
According to recent findings, as the duration of tamoxifen treatment increases, the risk of cancer of the uterine lining increases two-to-fourfold, compared to women who do not receive tamoxifen.
Hot flashes and other side effects such as menstrual disorders are in part due to the effects of tamoxifen, which suppresses as desired the effect of the female sex hormone estrogen.
What interactions does tamoxifen show?
Please note that the interactions may vary depending on the drug formulation of a drug (eg tablet, syringe, ointment).
Hormone supplements, especially estrogens, cause an effect of Tamoxifen.
Co-administration of tamoxifen with letrozole, which prevents the formation of estrogens (belongs to the subgroup of aromatase inhibitors), reduced the blood content of letrozole by 37%. Therefore, the combination of both agents has no sense.
Tamoxifen increases the risk of bleeding in combination with antiplatelet agents. The same applies to the simultaneous use of coumarin-type anticoagulants such as warfarin. Again, careful medical supervision of the blood clotting should take place.
Tamoxifen appears to increase the risk of blood vessel obstruction. Concomitant treatment with chemotherapeutic agents such as antibiotics or other cytotoxic agents increases this frequency.
Drugs that inhibit the enzyme CYP2D6 also hinder the action of tamoxifen. Thus, the blood content of the active conversion product endoxifen decreases by up to 75%. The decreased efficacy of tamoxifen leads to increased mortality of cancer patients. Co-administration of antidepressants of the group of selective serotonin reuptake inhibitors (such as paroxetine) or other antidepressants such as fluoxetine or bupropion, the antiarrhythmic drug quinidine and cinacalcet (in case of hyperparathyroidism) should be avoided as far as possible. In the case of antidepressants, the doctor may choose venlafaxine as an alternative, as it does not interfere with the enzyme.