2-PHENYL-1,3-INDANDIONE

Absorption

Absorbed slowly from the gastrointestinal tract.

Toxicity

Oral, mouse: LD50 = 175 mg/kg; Oral, rat: LD50 = 163 mg/kg.

Description

Phenindione is an anticoagulant and vitamin K antagonist. It inhibits the reduction of vitamin K₁ epoxide to vitamin K₁ by vitamin K₁ epoxide reductase in rat liver homogenates in a concentration-dependent manner. In vivo, phenindione (500 mg/kg) inhibits prothrombin synthesis and conversion of vitamin K₁ epoxide to vitamin K₁ in rats by 50 and 57%, respectively. Dietary administration of phenindione (4 mg/kg per day) inhibits aortic atherosclerosis or intracardial thrombosis in rat models of diet-induced atherosclerosis or intravascular thrombosis, respectively.

Chemical properties

light yellow fluffy fine flakes

The Uses of 2-PHENYL-1,3-INDANDIONE

Oral anticoagulant (indanedione).

The Uses of 2-PHENYL-1,3-INDANDIONE

Like coumarin derivatives, phenindione, a compound of the indandione class, acts by altering biosynthesis of coagulant proteins in the liver. It is used for preventing and treating thrombosis, thrombophlebitis, and thromboembolism. However, because of a number of side effects such as polyurea, polydipsia, tachycardia, and others, it is rarely used in practical medicine.

Definition

ChEBI: Phenindione is a beta-diketone and an aromatic ketone. It has a role as an anticoagulant. It derives from a hydride of an indane.

Background

An indandione that has been used as an anticoagulant. Phenindione has actions similar to warfarin, but it is now rarely employed because of its higher incidence of severe adverse effects. (From Martindale, The Extra Pharmacopoeia, 30th ed, p234)

Indications

For the treatment of pulmonary embolism, cardiomyopathy, atrial fibrillation and flutter, cerebral embolism, mural thrombosis, and thrombophili. Also used for anticoagulant prophylaxis.

brand name

Hedulin (Sanofi Aventis).

Pharmacokinetics

Phenindione thins the blood by antagonizing vitamin K which is required for the production of clotting factors in the liver. Anticoagulants such as Phenindione have no direct effect on an established thrombus, nor do they reverse ischemic tissue damage (damage caused by an inadequate blood supply to an organ or part of the body). However, once a thrombus has occurred, the goal of anticoagulant treatment is to prevent further extension of the formed clot and prevent secondary thromboembolic complications which may result in serious and possibly fatal sequelae. Phenindione has actions similar to warfarin, but it is now rarely employed because of its higer incidence of severe adverse effects.

Clinical Use

Anticoagulant

Synthesis

Phenindione, 3-phenylindan-1,3-dion (24.1.16), is synthesized in two ways. The first consists of condensating benzaldehyde with phthalide in the presence of sodium ethoxide. Evidently, the resulting phenylmethylenphthalide (24.1.15) rearranges under the reaction conditions to give the desired phenindione (24.1.16). The second method consists of condensation of phenylacetic acid with phthalic anhydride, forming phenylmethylenphthalide (24.1.15), which rearranges further in the presence of sodium ethoxide to phenindione.

Drug interactions

Potentially hazardous interactions with other drugs There are many significant interactions with coumarins. Prescribe with care with regard to the following:
Anticoagulant effect enhanced by: alcohol, amiodarone, anabolic steroids, aspirin, aztreonam, bicalutamide, cephalosporins, chloramphenicol, cimetidine, ciprofloxacin, dronedarone, fibrates, clopidogrel, cranberry juice, danazol, dipyridamole, disulfiram, fibrates, grapefruit juice, levofloxacin, macrolides, metronidazole, nalidixic acid, neomycin, norfloxacin, NSAIDs, ofloxacin, paracetamol, penicillins, ritonavir, rosuvastatin, sulphonamides, thyroid hormones, testosterone, tetracyclines, tigecycline, tramadol, trimethoprim.
Anticoagulant effect decreased by: oral contraceptives, rifamycins, vitamin K.
Anticoagulant effects enhanced/reduced by: anion exchange resins, corticosteroids, dietary changes, enteral feeds.
Analgesics: increased risk of bleeding with IV diclofenac and ketorolac - avoid.
Anticoagulants: increased risk of haemorrhage with apixaban, dabigatran, edoxaban and rivaroxaban - avoid.
Ciclosporin: there have been a few reports of altered anticoagulant effect; decreased ciclosporin levels have been seen rarely

Metabolism

Hepatically metabolised. Metabolites of phenindione often colour the urine pink or orange.

Metabolism

Hepatic.

Purification Methods

Crystallise the dione from EtOH (m 156o) or CHCl3 (m 148-150o). [Beilstein 7 H 808, 7 III 4100, 7 IV 2570.]