Plaxitin

Uses

Plaxitin, used in combination with infusional 5-fluorouracil/leucovorin, is used for:

• Adjuvant treatment of stage III colon cancer in patients who have undergone complete resection of the primary tumor.
• Treatment of advanced colorectal cancer.

Plaxitin is also used to associated treatment for these conditions: Advanced Colorectal Cancer, Advanced Ovarian Cancer, Advanced Pancreatic Cancer, Chronic Lymphocytic Leukemia (CLL) - Refractory, Colon Cancer Stage III, Esophageal Cancers, Malignant Neoplasm of Stomach, Advanced biliary adenocarcinoma, Refractory Neuroendocrine Tumour, Refractory Non-Hodgkin's lymphoma, Refractory Testicular cancer

How Plaxitin works

Plaxitin undergoes nonenzymatic conversion to active derivatives via displacement of the labile oxalate ligand. Several transient reactive species are formed, including monoaquo and diaquo DACH platinum, which covalently bind with macromolecules. After activation, oxaliplatin binds preferentially to the guanine and cytosine moieties of DNA, leading to cross-linking of DNA, thus inhibiting DNA synthesis and transcription. Cytotoxicity is cell-cycle nonspecific.

Dosage

Plaxitin dosage

Intravenous (Adult)-

Adjuvant therapy in stage III colon cancer: In combination with fluorouracil/ leucovorin: 85 mg/m2 every 2 wk for 12 cycles. Dose to be given by IV infusion over 2-6 hr, dissolved in 250-500 ml of glucose 5%, every 2 wk; given for 12 cycles. After recovery from toxicity, reduce dose to 75 mg/m2. Administer before fluoropyrimidines.

Advanced colorectal cancer: In combination with fluorouracil/ leucovorin: 85 mg/m2 every 2 wk until disease progression or unacceptable toxicity. Dose to be given by IV infusion over 2-6 hr, dissolved in 250-500 ml of glucose 5%, . After recovery from toxicity, reduce dose to 65 mg/m2. Administer before fluoropyrimidines.

Reconstitute with 10 ml (for 50 mg vial) or 20 ml (for 100 mg vial) water for inj or 5% dextrose inj. Reconstituted solution must be further diluted with 250-500 ml of 5% dextrose inj before admin.

Side Effects

Fatigue, fever, pain, headache, insomnia, nausea, diarrheoa, vomiting, abdominal pain, constipation, anorexia, stomatitis, anemia, thrombocytopenia, leukopenia, aspartate and alanine transaminases increased, total bilirubin increased, peripheral neuropathy, back pain, dyspnoea, cough, oedema, chest pain, peripheral oedema, flushing , thromboembolism, dizziness, rash, alopecia , hand-foot syndrome dehydration, hypokalaemia, dyspepsia, taste perversion, flatulence, mucositis, gastroesophageal reflux, dysphagia, dysuria, neutropenia, inj site reaction, rigors, arthralgia, abnormal lacrimation, serum creatinine increased, rhinitis, epistaxis, pharyngitis, pharyngolaryngeal dysesthesia, allergic reactions, hiccup.

Toxicity

There have been five cases of oxaliplatin overdose reported. One patient received two 130 mg/m2 doses of oxaliplatin (cumulative dose of 260 mg/m²) within a 24-hour period. The patient experienced Grade 4 thrombocytopenia (3) without any bleeding, which resolved. Two other patients were mistakenly administered oxaliplatin instead of carboplatin. One patient received a total oxaliplatin dose of 500 mg and the other received 650 mg. The first patient experienced dyspnea, wheezing, paresthesia, profuse vomiting and chest pain on the day of administration. She developed respiratory failure and severe bradycardia, and subsequently did not respond to resuscitation efforts. The other patient also experienced dyspnea, wheezing, paresthesia, and vomiting. Most common adverse reactions (incidence ≥ 40%) were peripheral sensory neuropathy, neutropenia, thrombocytopenia, anemia, nausea, increase in transaminases and alkaline phosphatase, diarrhea, emesis, fatigue and stomatitis.

Precaution

Should be administered under the supervision of an experienced cancer chemotherapy physician. Use appropriate precautions for handling and disposal. Monitor neurological status and dose should be reduced if symptoms are prolonged or severe. Monitor blood counts during treatment and courses should not be repeated until blood counts have recovered. Caution in elderly, moderate degrees of renal impairment. Avoid using aluminum-containing needles or IV admin sets that may come into contact with oxaliplatin as aluminum has been reported to cause degradation of platinum compounds.

Interaction

May decrease plasma levels of digoxin. May increase risk of toxicity with nephrotoxic drugs. When administered as sequential infusions, taxane derivatives (docetaxel, paclitaxel) should be administered before oxaliplatin to limit myelosuppression and enhance efficacy.

Food Interaction

Plaxitin Drug Interaction

Moderate: palonosetron, prochlorperazine, loperamide, polyethylene glycol 3350, pegfilgrastim, capecitabine, ondansetronUnknown: lorazepam, bevacizumab, diphenhydramine, docusate, dexamethasone, apixaban, fentanyl, omega-3 polyunsaturated fatty acids, acetaminophen, acetaminophen, cyanocobalamin, ascorbic acid, cholecalciferol

Plaxitin Disease Interaction

Major: arrhythmias, pulmonary toxicityModerate: neurologic toxicity, neutropenia, renal impairment, rhabdomyolysis, thrombocytopenia

Volume of Distribution

• 440 L [single 2-hour IV infusion at dose of 85 mg/m^2] At the end of a 2-hour infusion of oxaliplatin, approximately 15% of the administered platinum is present in the systemic circulation. The remaining 85% is rapidly distributed into tissues or eliminated in the urine.

Elimination Route

Bioavailability is complete following intravenous administration. When a single 2-hour intravenous infusion of oxaliplatin at a dose of 85 mg/m^2 is given, the peak serum concentration was 0.814 mcg/mL.

Half Life

The decline of ultrafilterable platinum levels following oxaliplatin administartion is triphasic, with two distribution phases: t1/2α; 0.43 hours and t1/2β; 16.8 hours. This is followed by a long terminal elimination phase that lasts 391 hours (t1/2γ).

Clearance

• 10 - 17 L/h [renal clearance]

Elimination Route

The major route of platinum elimination is renal excretion. At five days after a single 2-hour infusion of oxaliplatin, urinary elimination accounted for about 54% of the platinum eliminated, with fecal excretion accounting for only about 2%.

Pregnancy & Breastfeeding use

Category D: There is positive evidence of human foetal risk, but the benefits from use in pregnant women may be acceptable despite the risk (e.g., if the drug is needed in a life-threatening situation or for a serious disease for which safer drugs cannot be used or are ineffective).

Contraindication

Pregnancy. Peripheral neuropathy with functional impairment. Severe renal impairment.

Special Warning

Renal Impairment: Dose adjustment may be needed

Acute Overdose

Extensions of known adverse reaction (e.g. thrombocytopenia, myelosuppression, nausea, vomiting, neurotoxicity, respiratory symptoms). Treatment is supportive.

Storage Condition

Store intact vials at 15-30°C; do not freeze. Reconstituted solution: May store at 2-8°C for up to 24 hr. Diluted solutions: Stable up to 6 hr at 20-25°C or up to 24 hr under refrigeration at 2-8°C.

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