Tolbutamide hypoglycaemia

Dextropropoxyphene doe not appear to affect the pharmacokinetics of tolbutamide. Hypoglycaemia was seen in a patient taking an unnamed sulphonylurea with co-proxamol, and has also been reported in non-diabetic patients given dextropropoxyphene alone. 

Christesen HB, Melander A. Prolonged elimination of tolbutamide in a premature newborn with hyperinsulinaemic hypoglycaemia. Eur J Endocrinol 1998 138(6) 698-701. 

LEFLUNOMIDE ANTIDIABETIC DRUGS -TOLBUTAMIDE Possible T effect of tolbutamide Uncertain Monitor blood sugar closely. Watch for and warn patients about symptoms of hypoglycaemia - For signs and symptoms of hypoglycaemia, see Clinical Features of Some Adverse Drug Interactions, Hypoglycaemia... 

Andreasen PB, Simonsen K, Brocks K, Dimo B, Bouchelouche P. Hypoglycaemia induced by azapropazone tolbutamide interaction. Br J Clin Pharmacol 1981 12(4) 581-3. 

Sulphonylureas should ideally be avoided when the glomerular filtration rate is below 30 ml min-1, since hypoglycaemia may be expected in patients with renal failure associated with impaired liver function. Although tolbutamide can be given in normal doses to patients with renal failure (Hasselblatt, 1989), it is generally recommended not to be used in patients with severe impairment of renal function (Martindale, 1989). 

Chlorpropamide and tolbutamide are excreted in breast milk. Data on other sulphonylureas are not available. Because of the potential for hypoglycaemia in nursing infants, it has to be decided whether to discontinue nursing or to discontinue the drug. 

A further example is provided by the antidiabetic agent tolbutamide (Fig. 7.30) which was developed from a sulfonamide structure. Most sulfonamides are used as antibacterial agents, but some proved unsatisfactory since they led to convulsions brought on by hypoglycaemia (low glucose levels in the blood). Structural alterations were made to eliminate the antibacterial activity and to enhance the hypoglycaemic activity and this led to tolbutamide. 

Information is very limited. Only gliclazide has been implicated in severe hypoglycaemia with allopurinol and there seem to be no reports of either grossly enhanced hypoglycaemia with chlorpropamide and allopurinol, or a reduced effect with tolbutamide and allopurinol. More study is needed to find out whether any of these interactions has general clinical importance, but it seems unlikely. 

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