Generic Medicine Info
Indications and Dosage
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.
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.
Monitoring Parameters
Regularly monitor prothrombin time and assess the need for therapy.
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.
Mechanism of Action: 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.
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

Chemical Structure Image

Source: National Center for Biotechnology Information. PubChem Database. Phenindione, CID=4760, (accessed on Jan. 22, 2020)

MIMS Class
Anticoagulants, Antiplatelets & Fibrinolytics (Thrombolytics)
ATC Classification
B01AA02 - phenindione ; Belongs to the class of vitamin K antagonists. Used in the treatment of thrombosis.
Buckingham R (ed). Phenindione. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. ttps:// Accessed 17/10/2017.

Dindevan 25 mg Tablets (Mercury Pharma Group Ltd). MHRA. Accessed 23/11/2017.

Joint Formulary Committee. Phenindione. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. Accessed 17/10/2017.

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