Gemcitabine, commonly sold under the brand name Gemzar, is a chemotherapy medication. It interferes with the growth and division of cancer cells. It is administered through intravenous infusion.
How Gemcitabine Works
Gemcitabine is an antimetabolite, a type of chemotherapy drug that disrupts normal metabolic processes within cells. It acts as a nucleoside analog, mimicking deoxycytidine, a natural DNA building block. Once inside cancer cells, gemcitabine transforms into active forms: gemcitabine diphosphate (dFdCDP) and gemcitabine triphosphate (dFdCTP).
The active triphosphate form, dFdCTP, is mistakenly incorporated into newly synthesized DNA strands, leading to chain termination and preventing further elongation. Gemcitabine diphosphate (dFdCDP) also inhibits ribonucleotide reductase, an enzyme responsible for producing DNA synthesis precursors. This dual action disrupts DNA replication and repair within rapidly dividing cancer cells, leading to their death.
Cancers Treated with Gemcitabine
Gemcitabine is FDA-approved for treating several types of advanced cancers. It is a common treatment for pancreatic cancer, often as a first-line therapy, sometimes alone. For non-small cell lung cancer, gemcitabine is typically administered in combination with cisplatin for advanced or metastatic cases.
The drug also treats metastatic or unresectable breast cancer, usually in combination with paclitaxel. In ovarian cancer, gemcitabine is often a second-line treatment, combined with carboplatin, especially for recurrent cases after previous platinum-based therapy. It has also been studied for use in bladder cancer and other biliary tract cancers.
Receiving Gemcitabine Treatment
Gemcitabine is administered intravenously, typically as an infusion lasting about 30 minutes. Treatment schedules vary by cancer type and whether it is given alone or in combination. For some cancers, such as ovarian or breast cancer, it might be given on specific days every three weeks.
For non-small cell lung cancer, treatment might occur on certain days every three or four weeks. For pancreatic cancer, an initial cycle might involve weekly dosing for seven weeks, followed by a week of rest, with subsequent cycles involving weekly dosing for three out of four weeks. Before each treatment, patients typically undergo blood tests to monitor blood counts and organ function to ensure safe chemotherapy.
Managing Potential Side Effects
Patients undergoing gemcitabine chemotherapy may experience various side effects, including common ones like fatigue and nausea. Nausea and vomiting are often managed with anti-sickness medications. Hair thinning can occur, but it is generally less common and severe than with other chemotherapy drugs.
Myelosuppression, a reduction in blood cell production, is a common side effect, leading to low white blood cell counts (neutropenia), low red blood cell counts (anemia), and low platelet counts (thrombocytopenia). These low counts increase the risk of infection, fatigue, and bleeding, respectively. Healthcare providers closely monitor blood counts and may administer growth factors or recommend blood transfusions for severe anemia.
Flu-like symptoms, including fever, chills, headache, and muscle pain, are also common and managed with supportive care. Less common but more serious side effects include kidney or liver problems, monitored through blood tests. Patients are advised to stay hydrated, rest, and promptly report any new or worsening symptoms to their care team.