Withdrawal warfarin

Hematologic Rebound coagulation after warfarin withdrawal is supposed not to be a major risk, since the action of warfarin is only slowly reversible. However, rapid occurrence of an intraluminal thrombus... 

Alloul S, Dahdah N, Miro J. Thrombus in a coronary artery aneurysm shortly after warfarin withdrawal. Pediatr Cardiol 2009 30(2) 188-90. 

A contact dermatitis occurs infrequently. Because feverfew also inhibits human blood platelet aggregation, interactions are possible with antithrombotic medications such as aspirin or warfarin (Groenewegen and Heptinstall 1990). Abrupt discontinuation of feverfew by people taking it chronically for treatment of migraine can produce rebound withdrawal symptoms. These consist of migraines, anxiety, poor sleep patterns, and stiffness of the muscles and joints. 

Tea Tree (Melaleuca alternifolia) Uses Rx of superficial wounds (bacterial, viral, fungal, insect bites, minor burns, cold sores, acne Action Broad-spectrum antibiotic activity against E. coli, S. aureus, C. albicans Available forms Topical creams, lotions, oint, oil apply topically PRN Notes/SE Ataxia, contact dermatitis, D, drowsiness, GI mucosal irritation Interactions Effects OF drugs that affect histamine release EMS effects of Benadryl Valerian (Valeriana officinalis) Uses Anxiolytic, antispasmodic, dys-menorrheal, restlessness, sedative Action Inhibits uptake stimulates release of GABA, which T GABA concentration extracellularly causes sedation Available forms Ext 400-900 mg PO 30 min < hs, tea 2-3 g (1 tsp of crude herb) qid, PRN, tine 3-5 mL (1/2-1 tsp) (1 5 ratio) PO qid, PRN Efficacy Probably effective sedative (reduces sleep latency) Notes/SE GI upset, HA, insomnia, N/V, palpitations, restlessness, vision changes Interactions T Effects OF barbiturates, benzodiazepines, opiates, EtOH, catnip, hops, kavakava, passion flower, skullcap effects OF MAOIs, phenytoin, warfarin EMS T Effects of benzodiazepines and opiates abruptly D/C may cause withdrawal symptoms... 

Interactions. Oral anticoagulant control must be precise both for safety and efficacy. If a drug that alters the action of warfarin must be used, the INR should be monitored frequently and the dose of warfarin adjusted during the period of institution of the new drug until a new stable therapeutic dose of warfarin is identified careful monitoring is also needed on withdrawal of the interacting drug. 

In contrast, some penicillinase-resistant penicillins (dicloxacillin, nafcillin) provoke resistance to warfarin, lasting for up to 3 weeks after withdrawal of the antibiotic (331,332). 

From the therapeutic point of view, prophylaxis of thrombosis must be continued after withdrawal of heparin, since even when there is no evidence of thrombosis in association with heparin-induced thrombocytopenia, thrombosis can follow after some days (52). Because of cross-reactivity, low molecular weight heparin should not be used when heparin has been withdrawn because of heparin-induced thrombocytopenia nor should warfarin be used, because of the risk of venous gangrene, at least until the thrombocytopenia has resolved. Patients with life-threatening or limb-threatening thrombosis can be treated with thrombolytic drugs. Current views are that two antithrombotic drugs should be used, for example danaparoid plus lepirudin (58). 

A 61-year-old woman, who had taken warfarin for atrial fibrillation in weekly doses of 18-19 mg for years and had been completely stable, developed a raised INR after she consumed a tea made from Chinese wolfberry (14). Four days after drinking the tea (180 ml/day), she had an INR of 4.1. After withdrawal of the herbal tea her INR returned to within the target range and remained stable. 

A 61-year-old man, who had taken warfarin and simvastatin for a long time and had an INR of 2.4, started to take cucurbicin five tablets daily for micturition difficulties. After 6 days his INR had increased to 3.4. After withdrawal of cucurbicin the INR returned to the previous value within 1 week. 

Does the pharmacologic action of warfarin cease upon withdrawal of the drug ... 

Heparin acts very quickly to inhibit clot formation, whereas warfarin has a slow onset. Conversely, upon withdrawal of the drug, heparinized patients quickly recover, whereas the withdrawal of warfarin will have no appreciable effect for as much as several days. 

Which one of the following drugs has been used in the management of alcohol withdrawal states and in maintenance treatment of patients with tonic-clonic or partial seizure states Its chronic use may lead to an increased metabolism of warfarin and phenytoin. 

SSRI drug interactions The SSRls are inhibitors of hepatic cytochrome P450 isozymes, an action that has led to increased activity of other drugs including tricyclic antidepressants and warfarin. Huvoxamine inhibits the metabolism of cisapride, astemizole, and terfena-dine, and the resultant cardiotoxicity has led to the withdrawal of the latter two thugs (see Table 30-3). Citalopram causes fewer drug interactions than other SSRls. 

Some of this resistance to warfarin was undoubtedly due to the rifampicin (a known and potent inducer of warfarin metabolism) but as the ESTRs remained depressed for a further 20 days after rifampicin was withdrawn the authors suggested that the teicoplanin had its own part to play. However, rifampicin has been shown is several cases to decrease the ef-feets of warfarin for 3 or more weeks after its withdrawal (see Coumarins + Antibaeterials Rifamyeins p.375), so an interaction with teicoplanin would seem doubtful. 

Griffith LD, Olvey SE, Triplett WC, Stotter Cuddy ML. Increasing prothrombin times in a warfarin-treated patient upon withdrawal of Ensure Plus. Crit Care Med ( 9S2) 10,799-800. 

However, in one case report the prothrombin time of a woman taking warfarin, digoxin, captopril and prednisone rose from a range of 15 to 20 seconds up to 41 seconds within 4 days of starting moracizine 300 mg three times daily. She bled (haematemesis, haematuria), but responded rapidly to withdrawal of the warfarin and moracizine, and the administration of phytomenadione. ... 

A woman taking warfarin, insulin, levothyroxine and digoxin complained of menorrhagia at a routine follow up. Investigations revealed that her British Corrected Ratio had risen to 4.1 (normal range 2.3 to 2.8), and that one month previously she had started to take low-dose piracetam 200 mg three times daily. Within 2 days of withdrawing both the warfarin and piracetam her BCR had fallen to 2.07, and the original dose of warfarin was restarted. ... 

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