1 The effect of spontaneous changes in urinary pH on renal excretion and plasma concentration of mexiletine has been examined during chronic administration of subtherapeutic doses of the drug to healthy volunteers. 2 Significant correlations were found between urinary pH and the plasma concentration and renal excretion of mexiletine. 3 Prediction of plasma mexiletine concentrations from our data suggests that the amount of mexiletine in plasma would increase by more than 50% following a rise in urinary pH similar to that' which occurred spontaneously in our subjects. 4 Factors which influence urinary pH should be considered when the dosage of mexiletine is chosen. Extremes of urinary pH may account for some cases of inefficacy of the drug, and for the occurrence of unwanted effects at conventional doses. IntroductionMethods

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The cardiovascular effects of trazodone (TZD), amitriptyline (AMT) and placebo were studied in out-patients with major depression. AMT was shown to have the expected effects on the electrocardiograph and on systolic time intervals consistent with its proven anticholinergic and quinidine-like properties. TZD, in contrast, had no quinidine-like effects and minor effects on systolic time intervals. However, it was not without any cardiovascular effects. Although TZD was shown to be a safer preparation than the reference drug AMT, long-term monitoring is needed to explain the minor effect on heart rate and T wave changes.

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Treatment with azelastine 4.4 mg twice daily for 21 days did not produce any change in salivary antipyrine elimination in 8 normal volunteers.