Barbara R. Sommer

This paper reviews the clinical implications of topiramate (TPM)-induced cognitive deficits in patients with epilepsy, migraine headache, obesity, and in normal populations, followed by reviews of the literature describing the reversal of such deficits upon medication discontinuation. It also discusses animal investigations of TPM’s role of neuroprotection in brain injury. TPM’s most intolerable adverse effects (AEs) are on verbal fluency and reaction time, resulting in high discontinuation rates in patients taking it for epilepsy and migraine headache. However, because TPM is so effective in the treatment of epilepsy and migraine headache, its use is expected to continue. There appears to be greater tolerance of TPM’s cognitive AEs when it is used in the treatment of obesity, perhaps because of the lower doses required. Research attempting to predict the populations most vulnerable to the cognitive effects caused by TPM is ongoing. Studies suggest that one such population may include patients with a past psychiatric history. Slow titration and administration of the lowest possible doses may decrease risk of cognitive deficits.

Few controlled studies are available to guide the clinician in treating potentially assaultive elderly individuals with psychiatric disorders. Safety concerns limit the use of benzodiazepines and antipsychotic medications in the elderly individual, making anticonvulsants an attractive alternative. This paper reviews three specific anticonvulsants for this purpose: gabapentin, oxcarbazepine and topiramate, describing safety and efficacy in elderly patients with severe agitation from psychosis or dementia. Gabapentin, renally excreted, with a half-life of 6.5 – 10.5 h, may cause ataxia. Oxcarbazapine, hepatically reduced, may cause hyponatremia, and topiramate may cause significant cognitive impairment. Nonetheless, these are important medications to consider in the treatment of agitation.

Some fruit juices have very high potassium content. However, only several cases of juice-induced hyperkalemia have been reported that involved non-psychiatric, diabetic outpatients with renal compromise. We present a highly unusual case of a 66-year-old non-diabetic, schizophrenic woman with psychogenic polydipsia and normal renal function who developed hyperkalemia secondary to excessive orange juice consumption while an inpatient. In addition to demonstrating this previously undescribed medical comorbidity of schizophrenia, this case highlights the need for careful attention when communicating with both nursing and patients when managing psychogenic polydipsia.

Until the 1980s, the two major classes of antidepressants, the tricyclics and the monoamine oxidase inhibitors (MAOIs), were effective but had severe side effects, requiring monitoring by psychiatrists. The past several years have brought new classes of antidepressants that are safer for the patient to take and far easier for the non-psychiatrist to prescribe. Whilst this is of enormous value, it leaves the physician with the dilemma of which one to prescribe. These new antidepressants cannot safely be used interchangeably. This paper will discuss each of the antidepressants presently available, with particular emphasis on safety in the elderly. Drug interactions, side effects and particular challenges to the older patient will be described. The authors will then advise a general strategy for prescribing antidepressants.