Therapeutic monitoring antiepileptics

Antiepileptics e.g. Phenytoin Increase in gastrointestinal motility caused by cisapride may affect the rate and/or extent of absorption, which may be important for some drugs with a narrow therapeutic index, such as some antiepileptics. However, no available case reports to suggest this is a problem, and one case reporting no interaction. Uncertain. Monitor antiepileptic drug levels as usual practice. Advise the patient to report any increase in adverse effects. 1,7... 

Lehane, D.P. et al. 1976. Therapeutic drug monitoring Measurements of antiepileptic and barbiturate drug levels in blood by gas chromatography with nitrogen-selective detector. Ann Clin Lab Sci. 6 404. 

During the first half of the century, there was virtually an exclusive reliance on animal testing as the primary model for drug discovery and development. New chemical entities were administered to rodents in the primary screen assay, and the appropriate responses were monitored for indications of therapeutic potential. Compounds meeting the appropriate potency and efficacy criteria were promoted to more diverse and sophisticated animal models to characterize their pharmacological profile. The responses that were monitored included blood pressure (hypotensives), latency to respond to painful stimuli (analgesics), attenuation of seizure propensity (antiepileptics) and other responses that were intuitively and pharmacologically valid indicators of medicinal potential or toxicity. Some of these methods were semiautomated and quite sophisticated for their time, particularly for cardiovascular indications [1]. 

CARBAMAZEPINE PLATINUM COMPOUNDS 1 plasma concentrations of antiepileptic, which t risk of seizures Due to impaired absorption of antiepileptic Monitor closely for seizure activity, and warn patient and carers. Need to adjust dosage using parameters such as blood levels to ensure therapeutic levels... 

LOMUSTINE ANTIEPILEPTICS-PHENOBARBITAL 1 plasma concentrations of lomustine and risk of inadequate therapeutic response Phenobarbital induces the metabolism of lomustine by the CYP450 isoenzymes Avoid concurrent use. If necessaiy, t dose of lomustine and monitor therapeutic effects... 

TAMOXIFEN ANTIEPILEPTICS -CARBAMAZEPINE, PHENYTOIN, PHENOBARBITAL i plasma concentrations of tamoxifen and risk of inadequate therapeutic response Due to induction of metabolism of tamoxifen by the CYP3A isoenzymes by phenytoin Avoid concurrent use if possible. Otherwise monitor for clinical efficacy of tamoxifen by t dose of tamoxifen... 

CORTICOSTEROIDS ANTIEPILEPTICS -CARBAMAZEPINE, PHENYTOIN, PHENOBARBITAL 1 plasma concentrations of corticosteroids and risk of poor or inadequate therapeutic response, which would be undesirable if used for e.g. cerebral oedema Due to induction of the hepatic metabolism by the CYP3A4 isoenzymes Closely monitor therapeutic response - clinically, by ophthalmoscopy and radiologically - and t dose of corticosteroids for desired therapeutic effect... 

DOXYCYCLINE ANTIEPILEPTICS -BARBITURATES, CARBAMAZEPINE, PHENYTOIN i doxycydine levels, with risk of therapeutic failure Induction of hepatic metabolism Monitor for i clinical efficacy and t dose as required... 

Johannessen SI, Battino D, Berry DJ, Bialer M, Kramer G, Tomson T, Patsalos PN. Therapeutic drug monitoring of the newer antiepileptic drugs. Ther Drug Monit 2003 25 347-63. 

The usefulness of therapeutic drug monitoring has been demonstrated for some drugs (e.g., some antibiotics, cardiovascular agents and antiepileptics, theophylline, in-munosupressants, litium, methotrexate),and these are the drugs that are included in clinical pharmacokinetic programs in Spanish hospital pharmacy units. The be-... 

Garnett WR. Antiepileptics. In Schumacher GE, ed. Therapeutic Drug Monitoring. Norwalk, CT, Appleton and Lange, 1995 345-395. 

Kouno, Y Ishikura, C. Homma, M. Oka, K. Simple and accurate high-performance liquid chromatographic method for the measurement of three antiepileptics in therapeutic drug monitoring. J.Chromatogr, 1993, 622, 47-52... 

THEOPHYLLINE ANTIEPILEPTICS- BARBITURATES, CARBAMAZEPINE, PHENYTOIN i theophylline levels. Possibly i carbamazepine and phenytoin levels Due to induction of microsomal enzyme activity. Theophylline i absorption of phenytoin May need to T dose of theophylline by 25%. Monitor for inadequate therapeutic response to carbamazepine and phenytoin. Measure levels of these drugs... 

GRAPEFRUIT JUICE ANTIEPILEPTICS- CARBAMAZEPINE t in plasma concentrations of carbamazepine (AUC11,4-fold, maximum concentration t), which is of clinical significance because of the narrow therapeutic index of carbamazepine thus, toxic effects are likely, t efficacy and t adverse effects Grapefruit juice irreversibly inhibits intestinal CYP3A4. Transport via P-gp and MRP-2 efflux pumps is also inhibited Monitor fort side-effects/toxicity and check carbamazepine levels weekly. If levels or control of fits are variable, remove grapefruit and grapefruit juice from the diet... 

Therapeutic Drug Monitoring Measurement of Antiepileptic and Barbiturate Drug Levels in Blood by Gas Chromatography with Nitrogen-Selective Detector... 

---