Tetracycline Phenformin

Phillips PJ, PainRW, Phenformin, tetracycline and lactic acidosis. AnnIntemMed( 977) 86, 111. 

A few early reports indicated that the blood glucose-lowering effects of insulin and the sulphonylureas may sometimes be increased by oxytetracycline. There is also a case of hypoglycaemia involving insulin and doxycycline. Phenformin-induced lactic acidosis may be precipitated by tetracyclines. 

There are now at least 6 cases on reeord of lactic-acidosis in patients taking phenformin that were apparently precipitated by the concurrent use of tetracycline. " ... 

Aro A, Korhonen T, Halinen M, Phenformin-induced lacticacidosis precipitated by tetracycline. (1978) 1, 673-4,... 

The literature on the 3 most widely used biguanides, i.e. buformin, metformin and phenformin, continues to produce reports of lactic acidosis, mostly after phenformin (59 ). However, buformin (60 ) and excessive use of metformin (61 ) can also cause lactic acidosis. The complication is mostly seen in older patients, but a case has been reported involving a 30-year-old phenformin-treated patient with normal cardiac and renal function, who received tetracycline for fever and cervical adenopathy (62 ). 

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