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Objective: The study was designed to investigate the effect of haemodialysis on serum theophylline levels (STL).
Materials and Methods: Nine patients diagnosed with chronic obstmctive lung disease or bronchial asthma and who are already receiving theophylline treatment were included in the study (F:5, M:4). Their mean age and mean duration of haemodialysis were 51.2+6.8 years and 21.7+15.3 months respectively. Three patients were on 200 mg twice daily sustained release theophylline and 6 patients were receiving 300 mg twice daily. STLs were measured just before (11.00 am) and after (3.00 pm)- the haemodialysis sessions. Three days later when the patients came for their routine haemodialysis sessions their session was deferred from 11.00 am to 3-00 pm and their STLs were measured at 11.00 pm and 3.00 pm (non-haemodialysis period).
Results: Just before and after the haemodialysis sessions, mean STL values were 10.5+1.8 mg/1 and 6.2+1.5 mg/1 respectively (p<0.01). Mean initial and final STL values in the nonhaemodialysis period were 10.1+2.2 and 9.4+1.7 mg/1 (p>0.05). During the haemodialysis session STL values fell to subtherapeutic levels in 8 out of 9 patients (88%). This drop occurred in 1 of 8 patients (12.5%) during non-haemodialysis session. Overall theophylline clearance rate by haemodialysis was calculated as 35%.
Conclusion: One session of haemodialysis lowered STL to sub-therapeutic levels in the majority of patients. We therefore suggest that the dosage of theophylline needs to be adjusted accordingly. This can be done either by increasing the dose taken just before the haemodialysis or by the infusion of some additional theophylline during the haemodialysis session.