Phenytoin


Generic Medicine Info
Administration
Should be taken with food. When administering to patients on nasogastric or other enteral feeds, do not administer feeds 2 hr before or after a dose. Be consistent throughout therapy in relation to feed times. Do not switch dosage forms/brands w/o prior consideration.
Contraindications
History of acute hepatotoxicity attributable to phenytoin. Concomitant use with delavirdine. Inj: Sinus bradycardia, sino-atrial block, 2nd and 3rd degree AV block, Adams-Stokes syndrome.
Special Precautions
Patient with history of adverse haematologic reaction to any drug; diabetes mellitus, hypotension, cardiac disease; conditions associated with low serum albumin levels; hypothyroidism, porphyria. Critically ill, and debilitated patients. Patients who are positive for HLA-B*15:02 allele. Not indicated for the treatment of absence (petit mal) seizures, seizures due to hypoglycaemia or other metabolic causes. Avoid abrupt withdrawal. Hepatic and renal impairment. Elderly and children. Pregnancy and lactation. Patient Counselling This drug may cause dizziness and drowsiness, if affected, do not drive or operate machinery. Monitoring Parameters Monitor CBC, LFT, vitamin D status, plasma phenytoin concentrations? signs of suicidal ideation.
Adverse Reactions
Significant: Bone effects (e.g. osteopenia, osteoporosis, osteomalacia, bone fractures), vitamin D deficiency, hypocalcaemia, hypophosphataemia, acute hepatotoxicity, hypersensitivity, suicidal ideation and behaviour. IV: extravasation; hypotension, severe cardiac arrhythmia (rapid administration). Eye disorders: Nystagmus. Gastrointestinal disorders: Nausea, vomiting, constipation, gingival hyperplasia. Injury, poisoning and procedural complications: Injection site reactions. Immune system disorders: Anaphylactoid reactions, anaphylaxis. Musculoskeletal and connective tissue disorders: Purple glove syndrome. Nervous system disorders: Ataxia, slurred speech, decreased coordination, mental confusion (dose related); cerebellar atrophy (elevated phenytoin levels/long-term use); headache, dizziness, somnolence, motor twitching, paraesthesia, dysgeusia. Psychiatric disorders: Insomnia, transient nervousness. Skin and subcutaneous tissue disorders: Scarlatiniform or morbilliform rashes.
Potentially Fatal: Blood dyscrasias (e.g. agranulocytosis, leucopenia, granulocytopenia, thrombocytopenia, pancytopenia with or without bone marrow suppression); dermatologic reactions (e.g. acute generalised exanthematous pustulosis, toxic epidermal necrolysis, Stevens Johnson syndrome); multiorgan hypersensitivity reactions, drug reaction with eosinophilia and systemic symptoms (DRESS); hepatotoxicity.
Drug Interactions
Increased serum levels with salicylates; antibacterial agents (e.g. chloramphenicol, clarithromycin, isoniazid, sulfadiazine, sulfamethoxazole-trimethoprim, sulfonamides); anticonvulsants (e.g. oxcarbazepine, succinimides, topiramate); antifungal agents (e.g. amphotericin B, fluconazole, itraconazole, ketoconazole, miconazole); antineoplastic agents (e.g. capecitabine, fluorouracil); benzodiazepines/psychotropic drugs (e.g. disulfiram, methylphenidate, trazodone); CV agents (e.g. amiodarone, diltiazem, nifedipine); cimetidine, fluvastatin, tacrolimus, tolbutamide, omeprazole; serotonin re-uptake inhibitors (e.g. fluoxetine, fluvoxamine). Decreased serum levels with vigabatrin; antineoplastic agents (e.g. bleomycin, carboplatin, cisplatin, doxorubicin); sucralfate, reserpine, folic acid, rifampicin; antiretroviral (e.g. fosamprenavir, nelfinavir, ritonavir); theophylline, diazoxide. May increase or decrease serum levels with ciprofloxacin; psychotropic agents (e.g. chlordiazepoxide, diazepam, phenothiazines). May alter serum levels and/or effects of doxycycline; anticonvulsants (e.g. carbamazepine, lamotrigine, phenobarbital, Na valproate, valproic acid); antifungal agents (e.g. posaconazole, voriconazole); methotrexate; antiretrovirals (e.g. efavirenz, fosamprenavir, indinavir, lopinavir/ritonavir, ritonavir, saquinavir); theophylline; CV agents (e.g. digoxin, disopyramide, mexiletine, nicardipine, nimodipine, verapamil), warfarin, furosemide; HMG-CoA reductase inhibitors (e.g. atorvastatin, fluvastatin, simvastatin); oestrogens, oral contraceptives; neuromuscular blocking agents (e.g. pancuronium, rocuronium, vecuronium); methadone, tolbutamide; psychotropic agents/antidepressants (e.g. clozapine, paroxetine, quetiapine, sertraline); vitamin D.
CIMS Class
Anticonvulsants
ATC Classification
N03AB02 - phenytoin ; Belongs to the class of hydantoin derivatives antiepileptics.
Disclaimer: This information is independently developed by CIMS based on phenytoin from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to CIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, CIMS 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 © 2021 CIMS. All rights reserved. Powered by CIMSAsia.com
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