Gene Variants Variant effect Related antihistamines Ref.
Metabolic enzyme CYP3A5 *1/*1 High metabolic activity, low transport activity Rupatadine 45
*1/*3 Low metabolic activity, high transport activity 45
CYP3A4 *2 May lead to drug-drug interaction Cimetidine 47
*7
*16
*18;−392A>G (rs2740574)
CYP2J2 *8(G312R) Affects the structure of P450 heme Terfenadine 55
*9(P351L)
No effects No effects
*10(P115L)
CYP2D6
*1,*2
Extensive metabolizers
Asmiranzapine Mirtazapine Methiazine
60, 63-65
*3~*6 Poor metabolizers
*10,*41 Intermediate metabolizers
(CYP2D6*1)xN (CYP2D6*2)xN”
Ultrarapid metabolizers
Transport molecules ABCB1 1236C>T,2677G>A/T, 3435C>T Contradictory results Fexofenadine 75, 76
SLCO
2B1 (SLCO2B1c.[1457C>T] )
Reduced transport function
Fexofenadine
82 83
1B1 Not reported
1B3
Receptors HRH1 CT, TT Increase the incidence of AR and affect the curative effect 85
rs901865 G/G Increase sleepiness Desloratadine 103
HRH4 rs77041280(TA+TT) Reduce the efficacy of H1A orally 84
rs77485247(TA+AA)