Sulphasalazine induced selective IgA deficiency in rheumatoid arthritis.

and the mean observed peak plasma metoprolol concentration by about 33%. Furthermore, the elimination half life of metoprolol was prolonged from 3-9 hours during monotreatment to 6-0 hours when ranitidine was given in combination (p<0005). There was no evidence that any of the volunteers were poor metabolisers of metoprolol. Beta-blockade was assessed on the sixth treatment day by examining the inhibition of exercise induced tachycardia three and 12 hours after the morning dose. No significant difference between monotreatment with metoprolol or atenolol and each of the two drugs combined with ranitidine could be shown. This might be because the concentration response curve of the 5-receptor antagonist becomes very shallow at the upper range of plasma concentrations.