Contraindications
Fulvestrant should not be used in women with kidney failure or who are pregnant. Side effects
Very common (occurring in more than 10% of people) adverse effects include nausea, injection site reactions, weakness, and elevated transaminases. Common (between 1% and 10%) adverse effects include urinary tract infections, hypersensitivity reactions, loss of appetite, headache, blood clots in veins, hot flushes, vomiting, diarrhea, elevated bilirubin, rashes, and back pain. In a large clinical trial, the incidence of venous thromboembolism (VTE) with fulvestrant was 0.9%. Pharmacology
Pharmacodynamics
Fulvestrant is an antiestrogen which acts as an antagonist of the estrogen receptor (ER) and additionally as a selective estrogen receptor degrader (SERD). It works by binding to the estrogen receptor and making it more hydrophobic, which makes the receptor unstable and misfold, which in turn leads normal processes inside the cell to degrade it.In addition to its antiestrogenic activity, fulvestrant is an agonist of the G protein-coupled estrogen receptor (GPER), albeit with relatively low affinity (10–100 nM, relative to 3–6 nM for estradiol). Pharmacokinetics
Fulvestrant after an intramuscular injection is slowly absorbed and maximal levels (Cmax) are reached after 5 days on average with a range of 2 to 19 days. The elimination half-life of fulvestrant with intramuscular injection is 40 to 50 days. This is 40 times longer than the half-life of fulvestrant by intravenous injection, indicating that its long half-life with intramuscular injection is due to slow absorption from the injection site.
The severity of these symptoms varies greatly among patients: Some having scleroderma of only a limited area of the skin (such as the fingers) and little involvement of the underlying tissue, while others have progressive skin involvement. Digital ulcers—open wounds especially on fingertips and less commonly the knuckles—are not uncommon. Other organs
Diffuse scleroderma can cause musculoskeletal, pulmonary, gastrointestinal, renal, and other complications. Patients with greater cutaneous involvement are more likely to have involvement of the internal tissues and organs. Most patients (over 80%) have vascular symptoms and Raynauds phenomenon, which leads to attacks of discoloration of the hands and feet in response to cold. Raynauds normally affects the fingers and toes. Systemic scleroderma and Raynauds can cause painful ulcers on the fingers or toes, which are known as digital ulcers. Calcinosis (deposition of calcium in lumps under the skin) is also common in systemic scleroderma, and is often seen near the elbows, knees, or other joints. MusculoskeletalThe first joint symptoms that patients with scleroderma have are typically nonspecific joint pains, which can lead to arthritis, or cause discomfort in tendons or muscles. Joint mobility, especially of the small joints of the hand, may be restricted by calcinosis or skin thickening. Patients may develop muscle weakness, or myopathy, either from the disease or its treatments. LungsSome impairment in lung function is almost universally seen in patients with diffuse scleroderma on pulmonary function testing, but it does not necessarily cause symptoms, such as shortness of breath.