Is there increased cerebral sensitivity to benzodiazepines in chronic liver disease?

The use of psychotropics in the medically ill

Underlying medical illness may present a challenge when prescribing psychotropic medications. Disease-related changes in pharmacokinetics and pharmacodynamics, as well as vulnerability to side effects, polypharmacy, and potential drug interactions are all important considerations. Successful treatment of psychiatric disorders may have a beneficial impact on medical morbidity and mortality, as well as quality of life. This article reviews the relevant considerations when using psychotropic medications in six major medical populations (cardiac, cerebral vascular, pulmonary, liver, renal, and seizure disorders).

Psychiatric aspects of liver disease

This paper reviews the literature on the effects of liver disease on mental health, a topic which has been relatively neglected in the recent psychiatric literature. It discusses both the encephalopathy which may be associated with liver disease of almost any type and the psychological consequences of specific liver disorders. Also considered are the effects of liver disease on sexual function; the relationship between alcohol and hepatic disorder in causing mental disturbance; the effects of childhood liver disease; psychiatric aspects of liver transplantation; and the use of psychotropic drugs in patients with hepatic dysfunction.

Specific effects of the benzodiazepine midazolam on visual receptive fields in light and dark adapted human subjects

Psychophysical experiments in humans have revealed similar characteristics of visual receptive fields as were found in cats and monkeys from retinal ganglion cell recordings. In addition, in some retinal ganglion cells of cats the GABA antagonist bicuculline decreases the activity of the inhibitory surround. These findings led to two predicitions: 1) benzodiazepines will selectively increase the inhibitory surround of human visual receptive fields, 2) after dark adaptation, no free GABA will be available in the synapses and benzodiazepines will have no effect on the visual system. Characteristics of human receptive fields were determined by subthreshold summation: the contrast threshold of a vertical line was measured dependent on the distance of two parallel flanking lines whose contrast was below threshold. Both hypotheses were confirmed: the threshold in the inhibitory region of receptive fields was specifically increased in a dose-dependent manner by midazolam PO (7.5 mg: P < 0.05; 15 mg: P < 0.01). In dark-adapted subjects no effect of midazolam was found. Control experiments with atropine (1 mg IV), sulpiride (100 mg IM), and levodopa (100 mg PO) showed no specific effect. The visual system may be a model to bridge the gap between animal and human psychopharmacology.

Psychopharmacology in patients with hepatic and gastrointestinal disease

Psychotropic drugs often need to be prescribed to patients who also have pre-existing gastrointestinal (GI) and/or hepatic disease. This paper addresses the effect of GI and hepatic disease on the pharmacokinetics of psychotropic drugs, the effect of psychotropic drugs on pre-existing GI and hepatic diseases, the adverse GI and hepatic effects of psychotropic medications, the effects of GI medications on mental status, and the potential drug interactions between commonly prescribed GI medications and psychotropic drugs. Drug selection and dosage modification based on these considerations should allow safe and effective psychotropic treatment for patients with pre-existing GI and/or hepatic disease.