Phenindione


Concise Prescribing Info
Indications/Uses
Thromboembolic disorders.
Dosage/Direction for Use
Adult : PO Initial: 200 mg on day 1, then 100 mg on day 2. From day 3, adjust dose according to coagulation tests. Maintenance: 50-150 mg/day (resistant patients may require ≥200 mg/day while sensitive patients may require <50 mg/day).
Dosage Details
Oral
Thromboembolic disorders
Adult: Initially, 200 mg on day 1 followed by 100 mg on day 2. From day 3, adjust dose according to coagulation tests. Maintenance: 50-150 mg daily (resistant patients may require ≥200 mg daily while sensitive patients may require <50 mg daily).
Elderly: Dosage reduction may be needed.
Renal Impairment
Severe: Contraindicated.
Hepatic Impairment
Severe: Contraindicated.
Contraindications
Hypersensitivity. Significant bleeding, haemorrhagic conditions (e.g. haemorrhagic stroke), bacterial endocarditis, uncontrolled HTN; w/in 48 hr postpartum. Severe renal and hepatic impairment. Pregnancy and lactation. Concomitant use of fibrinolytic agents.
Special Precautions
Patient w/ risk factors for bleeding (e.g. risk of falling, cerebrovascular disease, serious heart disease, anaemia, malignancy, trauma); genetic variability in relation to VKORC1, recent ischaemic stroke, previous GI bleeding, active peptic ulcers, hyper- or hypothyroidism, acute illnesses; wt loss/gain, protein C or S deficiency, hyperphosphataemia, hypercalcaemia, hypoalbuminaemia. Patient undergoing surgery. Mild to moderate renal impairment. Elderly.
Adverse Reactions
Significant: Hypersensitivity reactions (including fever, lymphadenopathy, agranulocytosis, eosinophilia, leukocytosis, pancytopenia, leukaemoid syndrome, diarrhoea, vomiting, jaundice, rash, alopecia, skin necrosis, exfoliative dermatitis, renal damage w/ tubular necrosis, albuminuria), haemorrhage. Rarely, calciphylaxis.
Nervous: Cerebral haemorrhage, cerebral subdural haematoma.
CV: Haemorrhage.
GI: GI haemorrhage, rectal haemorrhage, haematemesis, pancreatitis, dysgeusia, nausea, melaena.
Resp: Haemothorax, epistaxis.
Hepatic: Hepatitis.
Genitourinary: Pink- or orange- coloured urine, haematuria.
Haematologic: Decreased hematocrit, decreased Hb; leucopenia.
Dermatologic: Purpura, blue toe syndrome, ecchymosis, exanthema.
MonitoringParameters
Regularly monitor prothrombin time and assess the need for therapy.
Overdosage
Symptoms: Spontaneous bruising, haematomas, haematuria, rectal bleeding, haemorrhage into any internal organ. Management: Give activated charcoal if ingestion is recent (w/in 1 hr) and ingested amount is >0.25 mg/kg or more than the patient’s therapeutic dose. If prothrombin time is prolonged w/ no active bleeding, give vit K 0.5-1 mg by slow IV infusion. If w/ active bleeding, give fresh frozen plasma and vit K 1 mg by slow IV infusion. If w/ life threatening haemorrhage, give fresh frozen plasma or factor concentrate.
Drug Interactions
Risk of haemorrhage w/ antineoplastics. antiplatelets, unfractionated heparins and heparin derivatives, LMWH, NSAIDs, SSRIs, SNRIs, bivalirudin, clofibrate, dipyridamole, eptifibatide, fondaparinux, miconazole, prostacyclin, sulfinpyrazone. May cause potentiated effect w/ ACTH, allopurinol, amiodarone, amitriptyline/nortriptyline, cimetidine, dextropropoxyphene, disulfiram, glucagon, phenformin, propafenone, thyroid compd, tolbutamide, zafirlukast, broad spectrum antibacterials, steroids, OCs. Antagonised effect w/ barbiturates, carbamazepine, griseofulvin, phenytoin. Decreased absorption w/ cholestyramine, sucralfate.
Potentially Fatal: Significantly increased risk of haemorrhage w/ fibrinolytic agents (e.g. streptokinase, alteplase).
Food Interaction
Reduced effects w/ ingestion of food rich in vit K.
Action
Description: Phenindione is an indanedione anticoagulant. It antagonises the effects of vitamin K and interferes w/ the formation of clotting factors II, VII, IX and X.
Onset: 36-48 hr.
Duration: 48-72 hr.
Pharmacokinetics:
Absorption: Rapidly and completely absorbed from the GI tract. Time to peak plasma concentration: 1-3 hr.
Distribution: Crosses placenta and enters breast milk.
Excretion: Via urine (as metabolites).
Chemical Structure

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ATC Classification
B01AA02 - phenindione ; Belongs to the class of vitamin K antagonists. Used in the treatment of thrombosis.
Disclaimer: This information is independently developed by MIMS based on Phenindione from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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