In order to determine if age and comorbidity influence the tolerability of the cytoprotective agent amifostine, we compared side effects related to amifostine in patients > or = 70 years (group I) with patients < 70 years (group II). We evaluated 268 consecutive administrations of amifostine (119 in group I and 149 in group II, respectively), given i.v. at a dose of 740 mg/m(2) just before platinum-, taxol- or cyclophosphamide-based chemotherapy. Transient hypotension was the most common side effect occurring in association with amifostine. Decreases in systolic blood pressure > 20 mmHg were of similar frequency in both groups (27.1 versus 28.8% of amifostine infusions in group I and II, respectively). Hypotension did not result in medical sequelae in any of the patients. The amifostine infusion was interrupted 16 times in group I and 8 times in group II, respectively, mainly due to hypotension, but could be restarted after a few minutes in all patients except for three cases in group I. Patients in group II more often suffered from nausea/vomiting than in group II (20.8 versus 10.0% in group I). Other subjective symptoms (e.g. warmed, flushed sensation, sneezing, metallic taste, mouth dryness, dizziness and sleepiness) and hypocalcemia occurred with a similar frequency in both groups. Adverse effects associated with amifostine were not observed more frequently in elderly patients than in younger ones, although more elderly patients had a comorbidity than the younger ones.