A single report describes the re-emergence of labyrinthine 
symptoms in a patient taking 
betahistine with terfenadine. This interaction had been predicted on theor- etical grounds because 
betahistine is an analogue of histamine. 
Betahistine may therefore oppose the effects of all 
antihistamines. 
 The use of 
antihistamines should be carefully considered in patients taking 
betahistine.