Pilocarpine hydrochloride relieves xerostomia in chronic graft-versus-host disease: a sialometrical study

Bone marrow transplantation is considered to be the treatment of choice for various hematological and solid malignancies, as well as for bone marrow failure syndromes and some genetic diseases. Unfortunately, a great number of patients who receive allogeneic BMT suffer from graft-versus-host disease (GVHD) following the procedure. Xerostomia is considered to be one of the most annoying complications of chronic GVHD (cGVHD), and the rapidly growing number of BMT patients with prolonged survival renders GVHD-related xerostomia a major clinical problem. As pilocarpine hydrochloride has been shown to relieve xerostomia in other disease categories, we administered pilocarpine hydrochloride 30 mg/day to six cGVHD patients and measured their whole saliva, parotid and submandibular-sublingual flow rates in both resting and stimulated conditions. Mean values of flow rates of whole saliva in resting conditions at 2 weeks, 2 months and 6 months following administration of pilocarpine hydrochloride 30 mg/day were 0.71 +/- 0.12 ml/min, 0.59 +/- 0.07 ml/min and 0.56 +/- 0.11 ml/min, respectively. In stimulated conditions, mean values were 1.7 +/- 0.3 ml/min, 1.0 +/- 0.17 ml/min and 0.94 +/- 0.21 ml/min, respectively. The mean values of whole saliva flow rates under both conditions represented an increase of 224-284% and 134-247%, respectively (P < 0.01). The pattern and magnitude of parotid and submandibular-sublingual flow rate increases following pilocarpine hydrochloride administration were similar. Patients were followed for 6 months and demonstrated increased levels of secretion, with some reduction after the initial peak values. The medication was discontinued at 2 months and reinstated after 2 weeks in three patients. This resulted in rapid flow rate reduction followed by another profound increase. Contrary to the sialometrical analysis, the subjective scoring showed no fluctuations during the study period. We discuss these results in the context of the clinical experience of xerostomic patients in whom even a minute increase in secretion may be significant. Our results demonstrate that objective and subjective relief from xerostomia in cGVHD patients can be achieved with the routine oral administration of pilocarpine hydrochloride.