تسجيل الدخول

تسجيل

Pharmacology of drugs in saliva , Barbiturates and antiepileptic drugsc

المؤلف:  Sue Jickells , Adam Negrusz (Editors)

المصدر:  Clarkes Analytical Forensic Toxicology

الجزء والصفحة:  p178-179

2026-10-10

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Pharmacology of drugs in saliva

Barbiturates and antiepileptic drugsc

Wilson (1993) reviewed the attempts to use saliva for therapeutic drug monitoring of anticonvulsant drugs, including barbiturates. These drugs generally have a neutral or acidic pKa and many are highly protein bound in blood. Their saliva: plasma ratios are usually less than unity. For example, carbamazepine saliva levels correlate well with dose and blood concentrations. The saliva: plasma ratio for carbamazepine is 0.13–0.33 (Miles et al. 1991). However, the reported phenytoin saliva: plasma ratios vary from 0.01 to 0.25 (average 0.09) for blood total phenytoin and from 1.06 to 2.22 for blood free phenytoin. Phenytoin saliva concentrations do not correlate with blood concentrations or therapeutic effect. They do show compliance or noncompliance, and elevated levels are related to toxicity. Kamali and Thomas (1994) demonstrated, using atropine induced reductions in saliva flow rate, that the saliva: plasma ratio and saliva phenytoin concentrations were dependant on saliva flow rate, but that this did not account for all of the intra-individual variance in the saliva: plasma ratio for phenytoin. Phenobarbital saliva: plasma ratios of 0.31 0.63 have been reported (Mucklow et al. 1978; Nishihara et al. 1979; Wilson 1993). Dilli and Pilai (1980) reported a half-life for pentobarbital in saliva of 17–19 h and for amobarbital of 22–26 hours. Sharp et al. (1983) reported saliva secobarbital levels of 210+-40 lg/L at 3 hours after oral administration of 50 mg secobarbital. The saliva: plasma ratio was 0.30+-0.04. Van der Graaff et al. (1986) reported the pharmaco kinetics of hexobarbital in plasma and saliva. Wilson (1993) listed the following therapeutic ranges for saliva: carbamazepine 1.4–3.5 mg/L, phenobarbital 5.0–15 mg/L and diphenylhydantoin 1.0–2.0 mg/L. Fabris et al. (1989) reported on the influence of pH on saliva phenobarbital content in infants.