CROSS patient selection

Cimetidine crosses the blood-brain barrier and can cause confusion, particularly in elderly or sick individuals with compromised hepatic or renal function, and especially after intravenous treatment. Very rarely an acute confu-sional psychosis has been seen in a younger person (161). Delirium has been thought to be a particular problem with intravenous use, but this is more likely to be a reflection of patient selection. Depression has occasionally been attributed to cimetidine (162,163). 

Hurley JC. Prophylaxis with enteral antibiotics in ventilated patients selective decontamination or selective cross-infection Antimicrob Agents Chemother 1995 39 941-947. 

Allergy mediated by selective IgE to certain types of NSAIDs by which symptoms are caused exclusively by a specific group of NSAIDs and no cross-reactivity exists with the other groups of anti-inflammatories. In a study carried out with 26 methimazole-allergic patients with IgE-mediated reactions [33], 14 of which developed anaphylaxis, BAT showed a sensitivity of 42% with an optimum specificity of 100%. No other validated in vitro test exists to date for the diagnosis of this disorder and so it represents an essential aid to diagnosis. 

Since rifamycins are important drugs for the treatment of M. tuberculosis infection [36, 86, 87] the activity of rifaximin on and interference with this bacterium have been carefully studied. Indeed, a potential problem of the treatment with this antibiotic is represented by the possibility that even very low blood levels achieved by oral administration might be able to select mutants, cross-resistant to rifamycins [85], in patients treated for GI infections and harboring M. tuberculosis. 

Isoproterenol, a synthetic sympathomimetic amine acting selectively at both Pi - and P2-adrenoceptors, is also able to induce panic attacks in a subset of patients suffering from panic disorder. There is, however, a discrepancy in the findings, and the rehability and mechanisms of isoproterenol-induced panic remain to be clarified. It should also be emphasized that isoproterenol is not able to cross the blood-brain barrier. 

The first neurochemical evidence of a disturbed serotonin function in cognition came from the changes in serotonin and/or 5-hydroxyindoleacetic acid (5-HIAA) levels in a number of forebrain nuclei, the temporal and cingulate cortex, hippocampus, and other areas of the brain taken at autopsy from patients with senile dementia of the Alzheimer s type (Adolfsson et al. 1978 Arai et al. 1984 D. M. Bowen et al. 1979, 1983 A. J. Cross et al. 1983 Winblad et al. 1982). The depletions are regionally selective reductions in se-... 

Fluoxetine is a selective serotonin-reuptake inhibitor (SSRI) that produces a net increase in (post-synaptic motor neuron) serotonin delivery after 4-6 weeks of use. A double-blind, randomized cross-over trial compared fluoxetine to the tricyclic antidepressant agent protriptyline and placebo in 12 patients with sleep-disordered breathing [52], The group apnea-hypopnea index (AHI) improved with fluoxetine compared to placebo, but there was great variability of response and other measures of disordered sleep did not change. These potentially beneficial results in a small number of patients need to be replicated in well-designed larger studies to support a useful role in clinical practice. 

Fexofenadine is indicated for the relief of the symptoms of allergic rhinitis in adults and children 12 years of age and older. Fexofenadine is a selective antagonist of the Hi histamine receptor in the periphery of the body. Experimental studies demonstrated that the drug does not cross the blood-brain barrier. Fexofenadine is rapidly absorbed following oral administration. Very little of the drug is metabolized, with 80 percent excreted in the feces, and 11 percent in the urine. Its half-life is about 15 hours. In patients older than 65 years, the peak concentration was twice that of normal volunteers less than 65 years old. Renal impairment also results in increased plasma levels. Adverse effects are mild and infrequent, and include drowsiness, dyspepsia and fatigue. 

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