THE EFFECTS OF ANTIDEPRESSANT DRUGS ON SALIVARY FLOW AND CONTENT OF SODIUM AND POTASSIUM-IONS IN HUMAN PAROTID-SALIVA

Stimulated parotid saliva was collected, using the Carlson-Crittenden cup, from normal controls and patients on antidepressant drugs. The sa liva from patients using amitriptyline, dothiepin (tricyclics), fluoxe tine and paroxetine (selective serotonin re-uptake inhibitors; SSRI) w as analysed for flow rate, [Na+] and [K+], and was compared with that from unmedicated, non-depressed volunteers for all variables. The tric yclic antidepressants produced a significant reduction in how (amitrip tyline, p < 0.01; dothiepin, p < 0.05), and consequent decrease in [Na +] and increase in [K+]. These effects were presumably due to muscarin ic receptor blockade. The SSRIs produced no significant change in thes e variables. A prospective study of dothiepin in non-depressed patient s confirmed that it decreases stimulated parotid flow. This finding al so suggested that depression itself contributed little to the oral,dry ness observed in and reported by the depressed patients. The patients' subjective rating of oral dryness related well to a reduction in stim ulated flow. This applied to those taking either tricyclics or SSRI, b oth showing a reduced flow rate relative to control (p < 0.001 and p < 0.05, respectively). This amounted to a 58% reduction in flow rate in the tricyclic group. The data suggest that measurement of stimulated parotid salivary flow is a reliable indicator of drug-induced oral dry ness.