Primidone, diphenylhydantoin and phenobarbital

Gallagher, Brian B.; Baumel, Irwin; Mattson, Richard H.; Woodbury, Suzanne G.

doi:10.1212/wnl.23.2.145

Cited by 50 publications

(16 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Disorders of ocular motility including defective slow tracking (pursuit) movements and total ophthalmoplegia have been described in association with phenobarbital (Gallagher et al 1973). Such adverse effects probably only occur when toxic plasma concentrations are achieved.…”

Section: Phenobarbitalmentioning

confidence: 99%

Clinically Important Ocular Reactions to Systemic Drug Therapy

Rennie

1993

Drug Safety

View full text Add to dashboard Cite

Many systemically administered drugs produce ocular adverse effects. Fortunately, relatively few are capable of causing significant, irreversible visual impairment. It is the responsibility of every clinician when prescribing systemic therapeutic agents to be aware of potential adverse ocular reactions, to appreciate their significance, and to inform the patient of the potential risks of treatment. In instances where serious adverse reactions relate to the cumulative effects of prolonged treatment, it is the responsibility of the prescribing physician to institute appropriate methods of visual screening. In this respect, it is most important to obtain the necessary individual baseline measurements before treatment is commenced. Chloroquine retinopathy is probably the most feared of all adverse ocular reactions to systemic drug therapy. However, it occurs only rarely if the daily dosage of chloroquine does not exceed 250mg. Regular screening using automated perimetry is mandatory if prolonged therapy is contemplated. Amiodarone almost inevitably produces corneal deposits. These rarely produce symptoms, and resolve upon withdrawal of the drug. Optic neuropathy has recently been described with amiodarone. Systemic anticoagulant therapy may be associated with intraocular hemorrhage in patients with pre-existing disciform macular degeneration, and such agents should be used with caution in affected individuals. Systemic corticosteroids produce posterior subcapsular cataracts in susceptible individuals which may profoundly affect visual acuity. Although elevated intraocular pressure may also result from systemic therapy, the relationship between the pressure rise and development of glaucomatous changes remains unclear. Ethambutol may produce optic neuropathy if the daily dosage exceeds 15 mg/kg. The changes are usually reversible within a few weeks of stopping treatment. High doses of tamoxifen may produce a maculopathy with loss of visual acuity, if given for prolonged periods. The risk must be weighed against the benefits of treatment. Patients receiving more than 800 mg/day of thioridazine have developed retinopathy, which is usually reversible if detected early enough. Tricyclic antidepressants and other agents with anticholinergic properties may cause disturbances of accommodation and pupillary dilatation. The latter may rarely precipitate acute angle closure glaucoma in susceptible individuals.

show abstract

Section: Phenobarbitalmentioning

confidence: 99%

Clinically Important Ocular Reactions to Systemic Drug Therapy

Rennie

1993

Drug Safety

View full text Add to dashboard Cite

show abstract

“…It was felt that the administration of metharbital in an acute experiment would complicate analysis since two drugs would undoubtedly be under study simultaneously. Primidone, another virtually insoluble antiepileptic, is biotransformed to phenobarbital and phenylethylmalonamide, both of which exhibit anticonvulsant activity (Gallagher et al, 1973). Furthermore, both of the N-methylated agents cannot be made into soluble sodium salts, a fact which would have created serious methodologic problems.…”

Section: Discussionmentioning

confidence: 99%

Differential Selectivity of Several Barbiturates on Experimental Seizures and Neurotoxicity in the Mouse

et al. 1979

View full text Add to dashboard Cite

Six barbiturates with diverse time-action characteristics--thiopental, pentobarbital, butabarbital, phenobarbital, diphenylbarbiturate, and barbital--were evaluated for "anticonvulsant" and "neurotoxic" effects. For the former, the MES test, clonic seizures induced by pentylenetetrazol, 90 mg/kg, s.c., and maximal seizures produced by pentylenetetrazol, 200 mg/kg, s.c., were employed. For the latter, we used a rotorod technique. Time to peak activity in the MES test was employed as the time for other tests. Pentobarbital required at least neurotoxic doses to produce substantial "anticonvulsant" activity, its protective index ranging from 0.79 to 0.98 in the three tests. Among the drugs tested, phenobarbital and diphenylbarbiturate exhibited the most favorable protective indices, ranging from 2.71 to 3.41 for phenobarbital and from 3.85 to 5.0 for diphenylbarbiturate. Barbital, another drug with a prolonged duration of action, exhibited a range from 0.84 to 2.81. Although a prolonged duration of action is an important characteristic for antiepileptic activity, this property does not confer per se a favorable protective index.

show abstract

“…Usually these effects only occur when toxic plasma concentrations are achieved (Gallagher et al 1973).…”

Section: Phenobarbitonementioning

confidence: 99%