What blood values should be monitored with carbamazepine?
Plasma carbamazepine levels should be monitored on a regular basis. The therapeutic range is 4 to 12
mcg/L. Higher levels can lead to toxic symptoms consisting of initial adverse effects and also
hypertension, tachycardia, ECG changes, stupor, agitation, nystagmus, urinary retention, respiratory
depression, seizures, and coma. Children and elderly patient may develop toxicity levels below 12.
CBCheveryh3htoh4hmonths
AffectshRBC,hWBC,hPlatelets
Agranulocytosis,hAnemia
Whathishthehpharmacodynamicshofhcarbamazepine?h-
hANSWERhCarbamazepinehishmetabolizedhinhthehliverhandhhashthehuniquehabilityhtohinducehitshownh
metabolismh(autoinduction).hDuehtohautoinduction,hinitialhconcentrationshwithinhtherapeutichrangehm
ayhlaterhfallhdespitehgoodhcompliance.hIthalsohinduceshthehmetabolismhofhmanyhCYP450henzymeshand
hotherhsubstances.hSlowlyhbuthwellhabsorbedhhalfhlifehofhabouth30hhours,hshortenshtoh15hhourshwhe
nhgivenhrepeatedly
Thehexacthmechanismhofhactionhofhcarbamazepinehishnothknown,hbuththeyharehthoughthtohaffecththeh
sodiumhchannels,hslowinghinfluxhofhsodiumhinhthehcorticalhneuronshandhslowinghthehspreadhofhabnor
malhactivity.hCarbamazepinehexertshitsheffecthbyhdepressinghtransmissionhinhthehnucleushventralishant
eriorhofhthehthalamus.hThishareahishassociatedhwithhthehspreadhofhseizurehdischarge.h
•AbsorptionhandhDistribution
Carbamazepinehishabsorbedhthroughhthehstomach,hthehsuspensionhbeinghabsorbedhmorehquicklyhthan
hthehtablethform.hAbsorptionhfromhthehimmediate-
releasehtabletshishslowhandherratichbecausehofhitshslowhwaterhsolubility.hThehdrughishhighlyhlipophilic,
hresultinghinhhighhbodyhtissuehbinding.h
, •MetabolismhandhExcretionh
Excretionhishthroughhfeceshandhurine.h
Averagehbloodhlevelshofhcarbamazepinehoccurhapproximatelyh6hhourshafterhadministration.hHalf-
lifehcanhbehashlonghash65hhourshwithhinitialhdosing,hbuthishtypicallyh12htoh17hhourshashadministrationh
continues.hIthishnoteworthyhthaththehhalf-lifehafterhahsinglehdosehishmuchhlongerhthanhthehhalf-
lifehafterhlong-termhuse.hSteadyhstatehishattainedhinh2htoh4hdays.
Whathshouldhfamilieshbehtaughthregardinghthehmonitoringhofhseizurehactivity?h-
hANSWERhPatientshshouldhbehmonitoredhforhseizurehactivity,hseverity,handhduration.hPatienthshouldhc
arryhmedicalhidentificationhforhthehseizurehdisorder.hPatienthshouldhreporthanyhmoodhchangeshorhsuic
idalhthoughts.hPreventionhofhseizures.hDohnothabruptlyhendhmedicationhincreaseshriskhofhseizures
Whathelectrolytehimbalancehishnotedhwithhthehadministrationhofhtopiramate?h-
hANSWERhPatientshtakinghtopiramatehmayhhavehdecreasedhconcentrationshofhbicarbonatehduehtohinhi
bitionhofhcarbonichanhydrasehandhincreasedhrenalhbicarbonatehloss,hleadinghtohhyperchloremichmetab
olichacidosis.hSeverehmetabolichacidosishhashbeenhreportedhinhinfantshreceivinghahtopiramatehdosehof
h5mg/kg/
day.hSerumhbicarbonatehlevelshshouldhbehmonitoredhathbaselinehandhperiodicallyhthroughouththerapy
.
Whathishthehpregnancyhcategoryhforhvalproate?h-hANSWERhPregnancyhCategoryhX.
Whathinstructionshwillhyouhprovidehtohahwomanhwhohwantshtohgethpregnanthandhhashahseizurehdisor
derhcontrolledhwithhvalproate?h-hANSWERhSwitchhtohanotherhantiseizurehmedicationhsuchhashKeppra