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Gemcitabine: Wikis

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Gemcitabine
Systematic (IUPAC) name
4-amino-1-(2-deoxy-2,2-difluoro-β-D- erythro-pentofuranosyl)pyrimidin-2(1H)-on

2′,2′-difluoro-2′-deoxycytidine

Identifiers
CAS number 95058-81-4
ATC code L01BC05
PubChem 60750
DrugBank APRD00201
Chemical data
Formula C 9H11F2N3O4  
Mol. mass 263.198 g/mol
Pharmacokinetic data
Bioavailability  ?
Protein binding <10%
Metabolism  ?
Half life Short infusions 32-94 minutes
for long infusions 245-638 minutes
Excretion  ?
Therapeutic considerations
Pregnancy cat. D(US)
Legal status
Routes Oral, intravenous
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Gemcitabine (pronunciation: jem-SITE-a-been) is a nucleoside analog used as chemotherapy. It is marketed as Gemzar by Eli Lilly and Company.

Contents

Pharmacology

Chemically gemcitabine is a nucleoside analog in which the hydrogen atoms on the 2' carbons of deoxycytidine are replaced by fluorine atoms.

As with fluorouracil and other analogues of pyrimidines, the, the triphosphate analogue of gemcitabine replaces one of the building blocks of nucleic acids, in this case cytidine, during DNA replication. The process arrests tumor growth, as new nucleosides cannot be attached to the "faulty" nucleoside, resulting in apoptosis.

Another target of gemcitabine is the enzyme ribonucleotide reductase (RNR). The diphosphate analogue binds to RNR active site and inactivates the enzyme irreversibly. Once RNR is inhibited, the cell cannot produce the deoxyribonucleotides required for DNA replication and repair, and cell apoptosis is induced.[1]

Administration

Gemcitabine is administered by the IV route, since it is extensively metabolized by the gastrointestinal tract. Dose ranges from 1-1.2 g/m2 according to type of cancer treated.[2]

Indications

Gemcitabine is used in various carcinomas: non-small cell lung cancer, pancreatic cancer, bladder cancer and breast cancer. It is being investigated for use in oesophageal cancer, and is used experimentally in lymphomas and various other tumor types. Gemcitabine represents an advance in pancreatic cancer care. It is also not as debilitating as some other forms of chemotherapy.

A study reported in the Journal of the American Medical Association suggested that gemcitabine shows benefit in patients with pancreatic cancer who were felt to have successful tumor resections.[3]

Gemcitabine became first line treatment for bladder cancer Stage 4 with metastases in combination with cisplatin after a study with 405 patients showed similar efficacy but less toxicity compared to the former MVAC regimen.[4] This new CG-regimen involves taking cisplatin on day 2 and taking gemcitabine on days 1, 8, and 15. In July 2006 the FDA approved gemcitabine for use with carboplatin in the treatment of advanced ovarian cancer that has relapsed at least 6 months after completion of platinum-based (eg,carboplatin or cisplatin) therapy. Neutropenia was the most commonly reported adverse effect (90% of patients). Other serious adverse effects were mostly hematologic.

GemCarbo chemotherapy for lung cancer

GemCarbo chemotherapy, consisting of a combination of gemcitabine and carboplatin, is used to treat several different types of cancer, but is most commonly used to treat lung cancer.[5] GemCarbo chemotherapy is usually given as a day patient treatment, involving a blood test the day before, and the drugs are given by an infusion. The GemCarbo regimen is given as a 21-day cycle and on the first day of treatment the patient is given both the gemcitabine and carboplatin. On the same day of the following week (day eight) there is a drip of gemcitabine only. There then follows a rest period of two weeks which completes one cycle of chemotherapy. The next cycle of treatment is given after a rest period, which will be three weeks after the first injection. Usually 4–6 cycles of treatment are given over a period of 3–4 months and this makes up a course of treatment.

Side Effects

The following side effects are common (occurring in more than 30%) for patients taking Gemcitabine:

Flu-like symptoms(muscle pain, fever, headache, chills, fatigue) Fever (within 6–12 hours of first dose) Fatigue Nausea (mild) Vomiting Poor appetite Skin rash

Low blood counts. Your white and red blood cells and platelets may temporarily decrease. This can put you at increased risk for infection, anemia and/or bleeding.

Nadir: Meaning low point, nadir is the point in time between chemotherapy cycles in which you experience low blood counts.

Onset: none noted Nadir: 10–14 days Recovery: day 21

Temporary increases in liver enzymes Blood or protein in the urine

These are less common side effects (occurring in 10-29%) for patients receiving Gemcitabine:

Diarrhea Weakness Hair loss Mouth sores Difficulty sleeping Shortness of breath (see lung problems)

Not all side effects are listed above, some that are rare (occurring in less than 10% of patients) are not listed here. However, you should always inform your health care provider if you experience any unusual symptoms.

References

  1. ^ N. M. F. S. A. Cerqueira, P. A. Fernandes, M. J. Ramos (2007). "Understanding ribonucleotide reductase inactivation by gemcitabine". Chemistry, a European Journal 13 (30): 8507–15. doi:10.1002/chem.200700260.  
  2. ^ Chu E., DeVita V. T., "Physicians' Cancer Chemotherapy Drug Manual, 2007", Jones & Bartlett, 2007.
  3. ^ Oettle H, Post S, Neuhaus P, et al. (January 2007). "Adjuvant chemotherapy with gemcitabine vs observation in patients undergoing curative-intent resection of pancreatic cancer: a randomized controlled trial". JAMA 297 (3): 267–77. doi:10.1001/jama.297.3.267. PMID 17227978. http://jama.ama-assn.org/cgi/pmidlookup?view=long&pmid=17227978.  
  4. ^ J Clin Oncol 18: 3068. 2000.  
  5. ^ Macmillan GemCarbo chemotherapy

External links

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