Home Drug Guide Gemcitabine

Drug Guide

Generic Name

Gemcitabine

Brand Names Gemzar

Classification

Therapeutic: Antineoplastic agent

Pharmacological: Antimetabolite (nucleoside analog)

FDA Approved Indications

Pancreatic cancer
Non-small cell lung cancer (NSCLC)
Bladder cancer
Breast cancer

Mechanism of Action

Gemcitabine is a nucleoside analog that inhibits DNA synthesis, leading to apoptosis of rapidly dividing tumor cells. It incorporates into DNA during replication and inhibits DNA chain elongation.

Dosage and Administration

Adult: Typically 1000 mg/m² IV weekly for 30-minute infusions, with treatment cycles repeated every 2-3 weeks based on specific indication and response.

Pediatric: Limited data; use with caution, and dosing should be individualized based on body surface area and clinical judgment.

Geriatric: Dose adjustments may be necessary; monitor renal and hepatic function closely.

Renal Impairment: Adjust dose based on renal function; severe impairment requires caution.

Hepatic Impairment: No specific adjustment recommended, but hepatic function should be monitored.

Pharmacokinetics

Absorption: Administered intravenously; not absorbed orally.

Distribution: Widely distributed in body tissues, crosses the blood-brain barrier minimally.

Metabolism: Primarily metabolized in the liver and plasma via cytidine deaminase to inactive metabolites.

Excretion: Excreted mainly in urine; renal function influences clearance.

Half Life: Approximately 42 minutes.

Contraindications

Hypersensitivity to gemcitabine or any component of the formulation.

Precautions

Patients with renal or hepatic impairment; use with caution.
Monitor blood counts regularly due to myelosuppression.
Pregnancy category D: risk of fetal harm; use effective contraception during treatment.

Adverse Reactions - Common

Myelosuppression (neutropenia, thrombocytopenia, anemia) (Very common)
Nausea and vomiting (Common)
Fatigue (Common)
Rash (Common)

Adverse Reactions - Serious

Severe myelosuppression leading to infection or bleeding (Serious)
Hepatotoxicity (Serious)
Interstitial lung disease (Rare)
Anaphylactic reactions (Rare)

Drug-Drug Interactions

CYP1A2 inhibitors or inducers may affect gemcitabine metabolism.
Other marrow suppressants may increase risk of myelosuppression.

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor complete blood counts, hepatic and renal function before and during therapy; assess for signs of infection or bleeding.

Diagnoses:

Risk for bleeding
Impaired tissue perfusion related to myelosuppression

Implementation: Administer IV as prescribed; ensure hydration; monitor for adverse reactions; educate patient about infection risks.

Evaluation: Evaluate patient's blood counts, organ functions, and clinical response regularly.

Patient/Family Teaching

Report signs of infection (fever, chills), unusual bleeding, or bruising.
Follow instructions for blood tests.
Use effective contraception during treatment and for some time after.
Report any allergic reactions such as rash or difficulty breathing.

Special Considerations

Black Box Warnings:

Severe myelosuppression can lead to serious infections or bleeding.
Use with caution in patients with hepatitis B or C due to risk of reactivation.

Genetic Factors: Pharmacogenomic testing not routinely required.

Lab Test Interference: May cause falsely elevated serum bilirubin levels.

Overdose Management

Signs/Symptoms: Severe myelosuppression, mucositis, or organ toxicity.

Treatment: Supportive care; platelet transfusions, antibiotics for infections; no specific antidote available.

Storage and Handling

Storage: Store at 2-8°C. Protect from light.

Stability: Stable for up to 24 hours at room temperature after reconstitution.