Oncotrex 7.5mg Tablet 10s

Side Effects of Oncotrex 7.5mg Tablet 10s

Ulceration of the mouth and GI disturbances (e.g. stomatitis and diarrhoea), bone marrow depression, hepatotoxicity, renal failure, skin reactions, alopecia, ocular irritation, arachnoiditis in intrathecal use, megaloblastic anaemia, osteoporosis, precipitation of diabetes, arthralgias, necrosis of soft tissue and bone, anaphylaxis, impaired fertility. Potentially Fatal: Pulmonary reactions (e.g. interstitial lung disease); neurotoxicity (e.g. leukoencephalopathy, paresis, demyelination) with intrathecal use; foetal deaths.

Drug Interactions

Decreased effectiveness with folic acid and its derivatives. Potentially Fatal: Increased toxicity with NSAIDs and salicylates; probenecid; some penicillins; aminoglycosides neomycin and paromomycin; sulfonamides such as sulfafurazole and sulfamethoxazole; co-trimoxazole or trimethoprim; nephrotoxic agents (e.g. cisplatin); ciclosporin; etretinate. Synergistic enhancement of effects with fluorouracil. Increased bioavailability of mercaptopurine. Reduces serum-valproate concentrations. Reduced serum concentrations with colestyramine. Increased serum concentrations with omeprazole.

Contraindications

Severe renal or hepatic impairment, pre-existing profound bone marrow suppression in patients with psoriasis or rheumatoid arthritis, alcoholic liver disease, AIDS, pre-existing blood dyscrasias, pregnancy (in patients with psoriasis or rheumatoid arthritis), breast-feeding.

Mechanism of Action

Methotrexate is a folic acid antagonist that inhibits DNA synthesis. It irreversibly binds to dihydrofolate reductase, inhibiting the formation of reduced folates, and thymidylate synthetase, resulting in inhibition of purine and thymidylic acid synthesis. Absorption: Rapidly absorbed from the GI tract at low doses, higher doses are less well absorbed. Rapidly and completely absorbed after IM doses. Peak plasma concentrations after 1-2 hr (oral), 30-60 min (IM). Distribution: Tissues and extracellular fluids; crosses the blood-brain barrier and placenta; enters breast milk. Small amounts in saliva and breastmilk. 50% bound to plasma proteins. Bound as polyglutamate conjugates, bound drug may remain in the body for several mth, particularly in the liver . Metabolism: Partly by intestinal flora. Does not undergo significant metabolism at low dose therapy; 7-hydroxy metabolite is detected at high-doses. Excretion: Primarily via urine; small amounts in bile, faeces. Some evidence of enterohepatic recirculation. Interindividual variation exists, patients with delayed clearance are at an increased risk of toxicity.

Special Precautions

Hepatic or renal impairment, bone marrow depression, elderly, neonates. Ulcerative disorders of the GI tract. Monitor haematological, renal and hepatic function, and GI toxicity regularly.

How to Use

Take orally with food and water, as directed by your physician.

How to Store

Keep in a cool, dry place away from sunlight and moisture.

Safety Concerns

• Alcohol: Avoid during treatment.
• Breastfeeding: Not recommended.
• Pregnancy: Contraindicated.
• Liver/Kidney: Use with caution.

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