Phenobarbital interaction

Phenytoin Phenobarbital Interaction inconsistent and usually of limited clinical significance Inhibition of phenobarbital metabolism... 

Acetazolamide Phenobarbital Interaction probably of little clinical significance Unknown... 

Riegelman S, Rowland M, Epstein WL. Griseofulvin-phenobarbital interaction in man JAMA 1970213(3) 426-31. 

Jamali F, Axelson JE. Griseofulvin-phenobarbital interaction a formulation-dependent phenomenon. JP/iarw Sci (1978) 67, 466-70. 

Kapetanovic IM, Kupferberg HJ, Porter RJ, Theodore W, SchulmanE, Penry JK. Mechanism of valproate-phenobarbital interaction in epileptic patients. Clm Pharmacol Ther (1981) 29, 480-6,... 

Danilov, V.S. 1984. Phenobarbital interaction with bacterial luciferase from Photobacterium fischerii. Mikrobiologiya 54 587-591. 

Valerian Valeriana officinalis Restlessness, sleep disorders Rare if used as directed. May interact with the barbiturates (eg, phenobarbital), the benzodiazepines (eg, diazepam) and the opiates, (eg, morphine). 

The interaction of ketamine with each of the three anticonvulsant compounds was also tested. Ketamine, 15 mg/kg, a dose showing no anti-PTZ effect and causing no overt behavioral changes, potentiated the effect of phenobarbital (20 mg/kg) in delaying the clonic and tonic convulsive responses and lethality (figure 3). Ketamine also potentiated the ability of phenytoin (20 mg/kg) to delay... 

FIGURE 3. Interaction between ketamine and phenobarbital against... 

The results demonstrate anticonvulsant properties of PCP and ketamine in two quite different seizure models. On the one hand, ketamine was effective in antagonizing several components of PTZ activity. Others have previously reported anti-PTZ effects of ketamine. However, the present results demonstrate that the anticonvulsant effects of ketamine against PTZ seizures closely resembled the effects of phenobarbital in that both compounds delayed clonic convulsions and prevented tonic extension. Moreover, a low dose of ketamine, which alone showed no anticonvulsant effect or overt behavioral changes, potentiated the anti-PTZ effects of phenobarbita 1. These findings suggest that ketamine possesses selective anticonvulsant properties. The anticonvulsant mechanism of action for phenobarbital is not known. However, the similarities between ketamine and phenobarbital, and the interaction between the two compounds, suggest a common mechanism or site of acti on. 

Phenobarbital may act by interacting with GABA receptors, blocking high voltage-activated Ca channels, and blocking a-amino-3-hydroxy-5-meth-ylisoxazole-4-propionic acid and kainate receptors. 

Phenobarbital is a potent enzyme inducer and interacts with many drugs. The amount of phenobarbital excreted renally can be increased by giving diuretics and urinary atkalinizers. 

FIGURE IS Electrochromatograms obtained for the separation of basic drugs spiked in a human serum compared with a blank in a hydrophobic interaction CEC. Column 5 pm 300 A polysulfoethyl A particles, 20 cm packed length, 50 pm ID mobile phase ACN/TEAP buffer (80 20) applied voltage, 10 kV detection at 214 nm. Drugs (I) amobarbital (2) phenobarbital (3) barbital (4) caffeine (5) sulfanilamide (6) theophylline (7) 2,4-dimethylquinoline (8) propranolol. (Reproduced with permission from reference 76.)... 

Several animal studies indicate that chloroform interacts with other chemicals within the organism. The lethal and hepatotoxic effects of chloroform were increased by dicophane (DDT) (McLean 1970) and phenobarbital (a long-acting barbiturate) in rats (Ekstrom et al. 1988 McLean 1970 Scholler 1970). Increased hepatotoxic and nephrotoxic effects were observed after interaction with ketonic solvents and ketonic chemicals in rats (Hewitt and Brown 1984 Hewitt et al. 1990) and in mice (Cianflone et al. 1980 Hewitt et al. 1979). The hepatotoxicity of chloroform was also enhanced by co-exposure to carbon tetrachloride in rats (Harris et al. 1982) and by co-exposure to ethanol in mice (Kutob and Plaa 1962). Furthermore, ethanol pretreatment in rats enhanced chloroform-induced hepatotoxicity (Wang et al. 1994) and increased the in vitro metabolism of chloroform (Sato et al. 1981). 

Stevens JL, Anders MW. 1981. Effect of cysteine, diethyl maleate, and phenobarbital treatments on the hepatotoxicity of [IH]- and [2H]chloroform. Chem Biol Interact 37 207-217. 

CI2. Cucinell, S. A., Conney, A. H., Sansor, M., and Bums, J. J., Drug interactions in man lowering effect of phenobarbital on plasma levels of dicoumarol and diphenylhydantoin. Clin. Pharmacol. Thcr. 6, 420-429 (1965). 

Drugs that may interact with losartan include cimetidine, phenobarbital, fluconazole, indomethacin, and rifamycins. 

Drugs that may interact with clozapine include caffeine, SSRIs, benzodiazepines, risperidone, CYP1A2 induces/inhibitors, CYP3A4 inhibitors, phenobarbital, and ritonavir. 

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