Antiepileptic drugs dosages

Refractory status epilepticus that has failed to respond to one of these treatments, and has continued for more than 20-30 min, requires urgent action. The accepted strategy is to paralyze and ventilate the patient and administer an antiepileptic drug in sufficient dosage to suppress EEG evidence of seizure activity. The barbiturate anaesthetic thiopental (thiopentone), the benzodiazepine midazolam, and the anaesthetic propofol have all been used. What little comparative evidence there is remains inconclusive. Such treatment can only be carried out with facilities for artificial ventilation and intensive care, and effects can only be monitored by EEG recording. 

Seizure control in patients receiving enzyme-inducing antiepileptic drug (ElAEDs), hut not valproic acid PO Recommended as add-on therapy 50 mg once a day for 2 wk, followed by 100 mg/day in 2 divided doses for 2 wk. Maintenance Dosage may be increased by 100 mg/day every week, up to 300-500 mg/day in 2 divided doses. 

The appropriate use of antiepileptic drugs requires a thorough understanding of their clinical pharmacology, e.g., mechanism of action, pharmacokinetics, adverse reaction, dosage forms, and drug interactions. 

Armijo JA, Bravo J, Cuadrado A, Herranz JL, Lamotrigine serum concentration-to-dose ratio influence of age and concomitant antiepileptic drugs and dosage implications. Ther Drug Monit( 999)2, 182-190,... 

Armijo JA, Cuadrado A, Bravo J, ArteagaR. gabatrin serum ccncentration to dosage ratio influence of age and associated antiepileptic drugs. TherDrugMomt(l99T) 19,491-8... 

Other antiepileptic drugs. There were adverse reactions in four patients, including irritability in three children at dosages of 74, 142, and 150 mg/kg/day, and hyperactivity in a child at a dosage of 96 mg/kg/day. Adverse reactions occasioned withdrawal in one child (increased irritability in spite of administration of pyridoxine). Patients who had adverse reactions had the same rate of titration as in the rest of the study population. 

It is reasonable to use proprietary names when dosage, and therefore pharmaceutical bioavadability, are critical so that small variations in the amoimt of drug available for absorption can have big effects on the patient, e.g. drugs with low therapeutic ratio, digoxin, hormone replacement therapy, adrenocortical steroids (oral), antiepileptics, cardiac anti-arrhythmics, warfarin. Also, with the introduction of complex formulations, e.g. sustained-release, it is important clearly to identify these, and use of proprietary names has a role. 

Cyclodextrin-based drug delivery systems The hydrophilic cyclodextrins have been extensively )plied to enhance the oral bioavailabilily of steroids, cardiac glycosides, nonsteroidal anti-inflammatory drugs, barbiturates, antiepileptics, benzodiazepines, antidiabetics, vasodilators, etc. Delayed and prolonged release of diltiazem and molsidormine was achieved by their complexation with CD derivatives, modified release of nifedipine can be achieved by its complexation with 2-HP-P-CD fiirosemide and piretanide (loop diuretics) release can be modified after complexation with DM-P-CD. Prednisolone dosage forms can be optimized also by complex-formation with 2-HP-P-CD. 

These effects probably occur because these antiepileptics are potent liver enzyme inducers, which may increase the metabolism of teniposide by the liver and thereby reduce its levels. The authors of these reports therefore conclude that an increased dosage of teniposide will be needed in the presence of these antiepileptics to achieve systemic exposure to the drug comparable to that achievable in their absence. It may be preferable to use alternative antiepileptics (that are not enzyme inducers) in patients requiring teniposide. More study is needed. 

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