Femiano F et al., (2011) compared in a randomized, double blind, placebo controlled, parallel study the efficacy of saliva substitutes and citric acid long-term therapyfor oral dryness relief and unstimulated salivary flow in patients reporting drug-induced xerostomia.
54 patients reporting drug-induced xerostomia were randomly subdivided into 3 groups and respectively administered artificial saliva, 3% citric acid, ordistilled water in mouthwash 4 times a day for 30 days. The patients in group 1 received a salivary substitute (containing water, hydroxypropyl cellulose, sorbitol, dipotassium chloride, sodium chloride, magnesium chloride, calcium chloride, and potassium phosphate) with a neutral pH (~7) and were marked as the artificial saliva group. The patients in group 2 received a solution of citric acid (3% in essential water) with pH of ~3,5 and were marked as the citric acid group. The patients in group 3 received distilled water with a pH of 7 and were marked as the water group.
Patients underwent measurement of unstimulated whole saliva before and after they finished therapy and were asked to note in a daily diary any symptomatologic changes 15 minutes and 1 hour after each daily intake of test solution.
Fifteen minutes after solution intake, 12 patients (67%) belonging to the artificial saliva group, 9 (50%) from the citric acid group, and 2 (11%) from the water group reported significant symptomatologic improvement. One hour after solution intake, 7 patients (39%) from the artificial saliva group, 10 (56%) from the citric acid group, and 0 from the water group noted significant symptomatologic improvement. None of the drugs tested affected unstimulated whole saliva flow.
The medicaments used for the study were well tolerated, and no patient noted serious adverse effects in their diaries.
Authors concluded that both artificial saliva and citric acid provided immediate relief from oral dryness. Citric acid also provided a longer-lasting feeling of oral moistness at 1 hour after use owing to its protracted activity on salivary gland function.