Gemcitabine (brand name Gemzar)
This belongs to the drug class known as nucleoside analogs, meaning they have similar properties to the compound nucleoside that occurs naturally in the body. Gemcitabine is converted inside the cell to difluorodeoxycytidine diphosphate (dFdCDP) and difluorodeoxycytidine triphosphate (dFdCTP). This results in the drug working in two ways. The dFdCDP stops the enzyme ribonucleotide reductase from doing its job of converting ribonucleotides to deoxyribonucleotides. Without this conversion, new DNA cannot be created so that cells can divide to form new cells and damaged DNA can’t be repaired. The second action is that the dFdCTP is incorporated into DNA, resulting in DNA strand termination and apoptosis, or automatic cell death.
This is another drug that doesn’t differentiate between cancerous cells and normal cells, so it will work on any rapidly dividing cell. One of the side effects of this drug is the killing off of the rapidly dividing stem cells of the bone marrow, which can cause anemia.
There are common side effects to using gemcitabine including:
- Feeling of “crawling” on the skin or itching
- Constipation or diarrhea
- Flu-like symptoms, such as fever, cough, chills, and muscle aches
- Hair loss
- Loss of appetite
- Nausea (with the possibility of vomiting)
- Small red spots below the surface of the skin
These side effects generally disappear after treatment has been completed.
There are more severe side effects; however, which require an immediate call to the doctor:
- Allergic reactions, such as rash, hive, difficulty breathing, tightness in the chest, swelling of the face, lips, or tongue
- Abdominal pain
- Confusion or a feeling of being disoriented
- Dark urine, blood in the urine, painful or frequent urinating, difficulty urinating or decreased amount of urine
- Irregular or missed menstrual periods
- Irregular heartbeat
- Joint or muscle pain or numbness in the arms or legs
- Unusual bruising or bleeding
- Extreme fatigue
- Yellowing of the skin or eyes
- Swelling of the hands or feet
The combination of gemcitabine and cisplatin is recommended for the first-line
chemotherapy treatment of patients with inoperable, locally advanced,
or metastatic tumors. There are two possible schedules for the administration
of these drugs; however, according to the drug manufacturer, Eli Lilly,
neither one has been proven to be more effective than the other.
Using the 4-week schedule, gemcitabine is administered intravenously at 1000 mg/m2 (megagrams per square meter) over 30 minutes on Days 1, 8, and 15 of each 28-day cycle. Cisplatin is administered intravenously at 100 mg/m2 on Day 1 after the gemcitabine.
Using the 3-week schedule, gemcitabine is administered intravenously at 1250 mg/m2 over 30 minutes on Days 1 and 8 of each 21-day cycle. Cisplatin is administered intravenously at a dose of 100 mg/m2 on Day 1after the gemcitabine.
The doctor may have to adjust the dosage for blood toxicity based on the granulocyte (a type of white blood cell) and platelet counts taken on the day of therapy. If bone marrow suppression is discovered, therapy should be modified or suspended depending upon the severity of the situation. In addition, creatinine (metabolic waste product found in urine that is an indicator of kidney function), potassium, calcium, and magnesium should be carefully monitored.