{"id":4015,"date":"2025-03-31T18:11:55","date_gmt":"2025-03-31T18:11:55","guid":{"rendered":"https:\/\/kidneydiseaseclinic.net\/kdc\/fosphenytoin-sodium-txt\/"},"modified":"2025-03-31T18:11:55","modified_gmt":"2025-03-31T18:11:55","slug":"fosphenytoin-sodium-txt","status":"publish","type":"post","link":"https:\/\/kidneydiseaseclinic.net\/kdc\/fosphenytoin-sodium-txt\/","title":{"rendered":"Fosphenytoin sodium.txt"},"content":{"rendered":"

Fosphenytoin sodium <\/h1>\n

CLINICAL USE <\/H3>
\nControl of status epilepticus Seizures associated with neurosurgery or head injury when oral phenytoin is not possible

DOSE IN NORMAL RENAL FUNCTION <\/H3>Status epilepticus: Treatment: 20 mg PE\/kg (loading dose) \u2014by

IV infusion <\/H4>Maintenance: 4\u20135 mg PE\/kg daily in \u20141\u20132 divided dosesProphylaxis or treatment of seizures: 10\u2013 15 mg PE\/kg by

IV infusion <\/H4>; then convert to phenytoin or 4\u20135 mg PE\/kg daily in 1\u20132 divided doses

PHARMACOKINETICS <\/H3>
  • Molecular weight &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp :406.2<\/li>\n
  • %Protein binding &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp :95\u201399<\/li>\n
  • %Excreted unchanged in urine &nbsp &nbsp : 1\u20135<\/li>\n

  • Volume of distribution (L\/kg) &nbsp &nbsp &nbsp :4.3\u201310.8 litres<\/li>\n

  • half-life \u2013 normal\/ESRD (hrs)&nbsp &nbsp &nbsp :18.9 (IV), 41.2 (IM)\/Unchanged

    DOSE IN RENAL IMPAIRMENT <\/H3>

    GFR (mL\/MIN)<\/H4>
  • 20 to 50 &nbsp &nbsp : Reduce dose or rate by 10\u201325% and monitor carefully (except for status epilepticus)
  • 10 to 20 &nbsp &nbsp : Reduce dose or rate by 10\u201325% and monitor carefully (except for status epilepticus)
  • <10 &nbsp &nbsp &nbsp &nbsp &nbsp : Reduce dose or rate by 10\u201325% and monitor carefully (except for status epilepticus)

    DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES <\/H3>
  • CAPD &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp:Unlikely to be dialysed. Dose as for GFR <10 mL\/min<\/p>\n
  • HD &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp :Not dialysed. Dose as for GFR <10 mL\/min
  • HDF\/high flux &nbsp :Unlikely to be dialysed. Dose as for GFR <10 mL\/min
  • CAV\/VVHD &nbsp &nbsp &nbsp:Not dialysed. Dose as for GFR 10 to 20 mL\/min

    IMPORTANT DRUG INTERACTIONS <\/H3>Potentially hazardous interactions with other drugs\n
  • Analgesics: enhanced effect with NSAIDs; metabolism of methadone accelerated\n
  • Anti-arrhythmics: increased concentration with amiodarone; concentration of disopyramide and mexiletine reduced\n
  • Antibacterials: level increased by clarithromycin, chloramphenicol, isoniazid, metronidazole, co-trimoxazole and trimethoprim (+ antifolate effect); concentration increased or decreased by ciprofloxacin; concentration of doxycycline and telithromycin reduced; concentration reduced by rifampicin\n
  • Anticoagulants: increased metabolism of coumarins (reduced effect but also reports of enhancement)\n
  • Antidepressants: MAOIs, SSRIs and tricyclics antagonise anticonvulsant effect, concentration increased by fluoxetine and fluvoxamine; reduced concentration of mianserin, mirtazepine, paroxetine and possibly tricyclics; concentration reduced by St John\u2019s wort \u2013 avoid\n
  • Anti-epileptics: concentration of both drugs reduced with carbamazepine; concentration may also be increased by carbamazepine, ethosuximide, oxcarbazepine and topiramate; possibly reduced concentration of ethosuximide, active oxcarbazepine metabolite, primidone (but active metabolite increased), topiramate and valproate; reduced concentration of lamotrigine, tiagabine and zonisamide; primidone and valproate may alter concentration; concentration reduced by vigabatrin\n
  • Antifungals: reduced concentration of ketoconazole, itraconazole, posaconazole, voriconazole and possibly caspofungin \u2013 avoid with itraconazole, increase voriconazole dose and possibly caspofungin; levels increased by fluconazole, miconazole and voriconazole\n
  • Antimalarials: antagonise anticonvulsant effect; increased antifolate effect with pyrimethamine\n
  • Antipsychotics: antagonise anticonvulsant effect; aripiprazole concentration possibly reduced \u2013 increase aripiprazole dose; Fosphenytoin sodium.fOSPHeNYtOIN SODIUM 335metabolism of clozapine, quetiapine and sertindole increased\n
  • Calcium-channel blockers: levels increased by diltiazem; reduced concentration of diltiazem, felodipine, isradipine, nisoldipine and verapamil and possibly dihydropyridines, nicardipine and nifedipine\n
  • Ciclosporin: reduced ciclosporin levels Corticosteroids: metabolism accelerated (effect reduced)Cytotoxics: metabolism inhibited by fluorouracil; increased antifolate effect with methotrexate; reduced phenytoin absorption; reduced concentration of busulfan, etoposide and imatinib \u2013 avoid with imatinibDisulfiram: levels of phenytoin increased\n
  • Diuretics: concentration of eplerenone reduced \u2013 avoid concomitant use; increased risk of osteomalacia with carbonic anhydrase inhibitors; antagonises effect of furosemideOestrogens and progestogens: metabolism increased (reduced contraceptive effect)Sulfinpyrazone: concentration increased by sulfinpyrazone\n
  • Tacrolimus: reduced tacrolimus levels Theophylline: concentration of both drugs reduced\n
  • Ulcer-healing drugs: metabolism inhibited by cimetidine; absorption reduced by sucralfate; enhanced effect with esomeprazole and omeprazole

    ADMINISTRATION <\/H3>

    Reconstition<\/H4>\u2013

    Route <\/H4>IV, IM

    Rate of Administration <\/H4>Status epilepticus : 100\u2013150 mg PE\/min Treatment and prophylaxis of seizures: 50\u2013100 mg PE\/min

    Comments<\/H4>Dilute further when using for

    IV infusion <\/H4> with sodium chloride 0.9% or glucose 5% to 1.5\u201325 mg PE\/mL

    OTHER INFORMATION <\/H4>75 mg of fosphenytoin sodium is equivalent to 50 mg of phenytoin0.037 mmol of phosphate\/mg of fosphenytoinDecreased protein binding in renal failure Monitor ECG, BP and respiratory function during infusionWhen substituting IV, IM use same dose and frequency as for oral phenytoin, administer at a rate of 50\u2013100 mg PE\/minMay increase blood glucose in diabetic patientsSome is dialysed out, as not all PE is protein-boundHalf-life of fosphenytoin to phenytoin is 15 minutes; more rapid in renal failure due to reduced protein binding.
    \n","protected":false},"excerpt":{"rendered":"

    Fosphenytoin sodium CLINICAL USE Control of status epilepticus Seizures associated<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[7],"class_list":["post-4015","post","type-post","status-publish","format-standard","hentry","category-blog","tag-post-by-auto-php"],"_links":{"self":[{"href":"https:\/\/kidneydiseaseclinic.net\/kdc\/wp-json\/wp\/v2\/posts\/4015","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kidneydiseaseclinic.net\/kdc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kidneydiseaseclinic.net\/kdc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kidneydiseaseclinic.net\/kdc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kidneydiseaseclinic.net\/kdc\/wp-json\/wp\/v2\/comments?post=4015"}],"version-history":[{"count":0,"href":"https:\/\/kidneydiseaseclinic.net\/kdc\/wp-json\/wp\/v2\/posts\/4015\/revisions"}],"wp:attachment":[{"href":"https:\/\/kidneydiseaseclinic.net\/kdc\/wp-json\/wp\/v2\/media?parent=4015"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kidneydiseaseclinic.net\/kdc\/wp-json\/wp\/v2\/categories?post=4015"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kidneydiseaseclinic.net\/kdc\/wp-json\/wp\/v2\/tags?post=4015"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}