Pharmacristine

Uses

Pharmacristine sulfate injection is used for acute leukemia. Pharmacristine sulfate injection has also been shown to be useful in combination with other oncolytic agents in Hodgkin's disease, non-Hodgkin's malignant lymphomas (lymphocytic, mixed cell, histiocytic, undifferentiated, nodular and diffuse types), rhabdomyosarcoma, neuroblastoma, and Wilms' tumor.

Pharmacristine is also used to associated treatment for these conditions: Acute Lymphoblastic Leukaemia Recurrent, Acute Lymphocytic Leukemia (ALL), Choriocarcinoma, Chronic Lymphocytic Leukaemia (CLL), Ewing's Sarcoma, Gestational Trophoblastic Disease, Hepatoblastomas, Immune Thrombocytopenic Purpura ( ITP ), Kaposi’s sarcoma, Lymphoma, Hodgkins, Multiple Myeloma (MM), Neuroblastomas, Non-Hodgkin's Lymphoma (NHL), Ovarian germ cell tumour, Pheochromocytomas, Retinoblastoma, Rhabdomyosarcomas, Small Cell Lung Cancer (SCLC), Wilms' tumor, Advanced Thymoma

How Pharmacristine works

The antitumor activity of Pharmacristine is thought to be due primarily to inhibition of mitosis at metaphase through its interaction with tubulin. Like other vinca alkaloids, Pharmacristine may also interfere with: 1) amino acid, cyclic AMP, and glutathione metabolism, 2) calmodulin-dependent Ca²⁺-transport ATPase activity, 3) cellular respiration, and 4) nucleic acid and lipid biosynthesis.

Dosage

Pharmacristine dosage

Adult (Intravenous): Usual recommended dosage: 1.4-1.5 mg/m2 once wkly. Max: 2 mg wkly. Subsequent doses may be modified based on clinical and haematological responses and tolerance of the patient. May be used in combination with other drugs. Prescribers should consult published protocols for the dosage, method and sequence of admin.

Child (Intravenous): Usual recommended dosage: 1.5-2 mg/m2 once wkly; for patients ≤10 kg: Initiate at 0.05 mg/kg once wkly. Subsequent doses may be modified based on clinical and haematological responses and tolerance of the patient. May be used in combination with other drugs. Prescribers should consult published protocols for the dosage, method and sequence of admin.

Side Effects

Dose limiting neurotoxicity (e.g. motor function impairment, gait abnormalities), hyperuricaemia, bronchospasm, azospermia, amenorrhoea, alopoecia, leucopenia, urinary dysfunction, abdominal cramps, vomiting, diarrhoea, severe constipation, paralytic ileus, convulsions, hypertension, orthostatic hypotension, ptosis, hoarseness, optic neuropathies, hallucinations, blindness, neurological deafness, difficulty in walking, syndrome of inappropriate ADH secretion.

Toxicity

IVN-RAT LD₅₀ 1300 mg/kg; IPR-MUS LD₅₀ 5.2 mg/kg. Marqibo® must only be administered IV because it is fatal if administered by other routes. Marqibo® also has different dosing than vincristine sulphate injection, so attention is needed to prevent overdoses. The most clinically significant adverse effect of vincristine is neurotoxicity.

Precaution

Elderly. Preexisting pulmonary dysfunction or neuromuscular disease; leucopenia or a complicating infection; impaired liver function; obstructive jaundice. Routine prophylactic laxative needed to ensure regular bowel movement. Discontinue immediately if extravasation occurs, and inj any remaining drug into another vein, followed by local Inj of hyaluronidase and topical heat application to the affected area to aid in drug removal and reduce discomfort. Discontinue in patients who develop progressive dyspnea. CBC to be checked before each dose admin. Frequent monitoring of uric acid during first 3-4 wk of treatment and watch out for uric acid nephropathy.

Interaction

Decreased digoxin (tablets) and verapamil absorption with antineoplastic regimens. Increased etoposide serum levels with vincristine. Increased toxicity when ganciclovir given with, immediately before or after vincristine. Reduced vincristine metabolism with miconazole. Increased neurotoxicity with isoniazid, itraconazole, voriconazole, posaconazole and nifedipine. Decreased immune response when used concurrently with vaccines. Increased myelotoxicity with zidovudine. Increased risk of thromboembolic complications with tamoxifen. Increased risk of ototoxicity with ototoxic drugs (e.g. platinum-containing antineoplastic agents). Possible risk of earlier onset and/or increased severity of adverse effects with macrolides. Possible increase in vincristine levels with aprepitant. Possible decrease in antiepileptic levels with vincristine, monitor serum antiepileptic levels and effectiveness of chemotherapy.

Food Interaction

• Exercise caution with grapefruit products. Grapefruit inhibits CYP3A4 metabolism, which may increase the serum concentration of vincristine.
• Exercise caution with St. John's Wort. This herb induces CYP3A4 metabolism, which may reduce serum levels of vincristine.

Pharmacristine Drug Interaction

Moderate: pegfilgrastimMinor: doxorubicinUnknown: lorazepam, sulfamethoxazole / trimethoprim, diphenhydramine, sulfamethoxazole / trimethoprim, prochlorperazine, cyclophosphamide, meperidine, arginine, levocarnitine, cysteine, lithium, rituximab, acetaminophen, cyanocobalamin, cholecalciferol, phytonadione, menaquinone, ondansetron

Pharmacristine Disease Interaction

Major: pulmonary dysfunction, neurologic dysfunctionModerate: constipation, hepatic dysfunction, infections, myelosuppression, renal impairment, SIADH

Volume of Distribution

Within 15 to 30 minutes after injection, over 90% of the drug is distributed from the blood into tissue, where it remains tightly, but not irreversibly, bound.

Half Life

When intravenously injected into cancer patients, a triphasic serum decay patten was observed. The initial, middle, and terminal half-lives are 5 minutes, 2.3 hours, 85 hours respectively. The range of the terminal half-life is humans is 19 - 155 hours.

Elimination Route

The liver is the major excretory organ in humans and animals. 80% of an injected dose of vincristine sulfate is excreted via feces. 10 - 20% is excreted via urine.

Pregnancy & Breastfeeding use

Pregnancy 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

Patients with demyelinating form of Charcot-Marie-Tooth syndrome. Pregnancy and lactation. Intrathecal admin (may be fatal). Patients receiving radiation therapy through ports which include liver.

Special Warning

Hepatic Impairment: Dose adjustment may be needed. Serum bilirubin >3 mg/100ml: Reduce dose by 50%.

Acute Overdose

Symptoms: mainly extensions of its common adverse effects.

Management: Treatment is supportive and includes prevention of side effects from syndrome of inappropriate antidiuretic hormone secretion (SIADH) (e.g. fluid restriction and admin of loop diuretic); admin of anticonvulsants and use of enemas (to prevent ileus). Closely monitor the CV system and determine the blood counts daily to guide transfusion requirements. Folinic acid 100 mg admin IV every 3 hr for 24 hr and then every 6 hr for at least 48 h may be admin. Haemodialysis unlikely to be useful.

Storage Condition

Store at 2-8° C. Protect from light.

Innovators Monograph

You find simplified version here Pharmacristine