The chlorpropamide alcohol flush.

Many non-insulin dependent diabetics (NIDDs) on the sulphonylurea chlorpropamide experience intense facial flushing after taking alcohol even in small amounts. This chlorpropamide alcohol flush (CPAF) was first recognized within months of the introduction of the drug in the 1950s [ l ] but, although an alcohol flush occasionally occurs with tolbutamide [ 2 , 31, it has not been reported with other sulphonylurea drugs. CPAF is a flush of the face and neck, sometimes involving the conjunctivae. A few patients also describe a warmth and fullness of the hands but the flush is not seen elsewhere. Wheezing may also occur in those with pre-existing asthma [4, S]. The reaction is not distressing although it is often embarrassing. CPAF starts within 10-15 min of taking alcohol, reaches a peak in about 30 min and lasts for more than 90 min. It may be associated with a small increase in pulse rate but there is no change in blood pressure or sweating. CPAF begins within 2-5 days of starting chlorpropamide, continues for as long as it is taken and ceases within 4-7 days of stopping the drug. It does not appear to be dependent on the dose of alcohol, the rise of facial temperature being the same for doses of sherry varying from 10 to 100 ml, unlike simple alcohol flush which is dose dependent [6] (although in one recent study when a second, larger dose of alcohol was given the response increased [7]). When CPAF was first recognized it was regarded as a harmless side effect until 1978 when it