USES OF WARF 2 MG TABLET 15S:
Warfarin is an anticoagulant medicine (also called blood thinner). Warfarin prevents the formation of blood clots. Warfarin is used to treat or prevent blood clots in veins or arteries, which can reduce the risk of stroke, heart attack, or other serious conditions.
SIDE EFFECTS OF WARF 2 MG TABLET 15S:
Hypersensitivity, rash, alopecia, diarrhoea, drop in haematocrit, purple toes syndrome, skin necrosis, jaundice, nausea, vomiting, hepatic dysfunction, pancreatitis, increased LFT. Potentially Fatal: Haemorrhage (narrow therapeutic index).
DRUG INTERACTIONS OF WARF 2 MG TABLET 15S:
Potentially Fatal: Acute alcoholism, allopurinol, NSAIDs, anabolic steroids, amiodarone, propafenone, quinidine, chloramphenicol, ciprofloxacin, co-trimoxazole, erythromycin, metronidazole, ofloxacin, sulfonamides, azithromycin, clarithromycin, norfloxacin, tetracyclines, SSRI, fluconazole, itraconazole, miconazole, ketoconazole, proguanil, cisapride, ifosfamide, disulfiram, piracetam, zafirlukast, interferon-Î±, isoniazid, tramadol, glucagon, doxycycline, propylthiouracil, danazol, flutamide, tamoxifen, clofibrate, simvastatin, cimetidine, sulfinpyrazone enhance anticoagulant effect of warfarin. Drugs eg, rifampicin, carbamazepine, phenobarbital, barbiturates, bosentan, nafcillin, azathioprine, menthol, primidone, griseofulvin and aminoglutethimide, oral contraceptives containing oestrogens, corticosteroids, sucralfate, vit K as well as chronic alcoholism reduce anticoagulant effect. Cholestyramine may reduce anticoagulant effect, avoid admin of warfarin 1 hr before or 4-6 hr after cholestyramine.
CONTRAINDICATIONS OF WARF 2 MG TABLET 15S:
Hypersensitivity; haemorrhagic tendencies or blood dyscrasia; recent surgery; peptic ulcer; severe hypertension; bacterial endocarditis; cerebrovascular disorders; psychosis; senility; aneurysms; pericarditis; pericardial effusion; eclampsia; pre-eclampsia; threatened abortion; alcoholism; severe renal and hepatic impairment; pregnancy.
MECHANISM OF ACTION OF WARF 2 MG TABLET 15S:
Warfarin inhibits synthesis of vit K-dependent coagulation factors VII, IX, X and II and anticoagulant protein C and its cofactor protein S. No effects on established thrombus but further extension of the clot can be prevented. Secondary embolic phenomena are avoided. Onset: 24 hr Duration: 2-5 days. Absorption: Absorbed readily from the GI tract (oral); used as racemic isomers, S-isomers more potent. Peak plasma concentration: within first 4 hr. Distribution: Protein binding: Extensive (99%) to albumin. Crosses placenta. Metabolism: Hepatic; mainly by the cytochrome P450 isoenzyme CYP2C9, which shows genetic polymorphism. Other enzymes involved include CYP2C19, CYP2C8, CYP2C18, CYP1A2, and CYP3A4. S-isomer is metabolised more rapidly than R-isomer. Excretion: Via urine (as metabolites after reabsorption from the bile); 37 hr (elimination half-life).
SPECIAL PRECAUTIONS FOR WARF 2 MG TABLET 15S:
Heparin induced thrombocytopenia, DVT, infectious disease, disturbances of intestinal flora, surgery or trauma, indwelling catheters, hypertension, Vit C, Vit K, protein C or S deficiency. Elderly, lactation, alcoholics. Purple toes syndrome (due to cholesterol microembolisation) may occur between 3-10 wk after start of therapy. Discontinue therapy if necrosis develops. Periodic determination of PT/INR. Patient to report any signs of bleeding, symptoms of blood clot and avoid activities or sports that can cause injuries. An INR <2 generally represents insufficient anticoagulation while INR>4 represents higher risk of bleeding.