Although it remains unclear whether the BBB permeability of these drugs is affected during preeclampsia, it is noteworthy that several antihypertensives, namely labetalol, nicardipine and nifedipine, are substrates of efflux transporters including P-GP (Thiel-Demby et al., 2009; Choi et al., 2013; Incecayir et al., 2013). This evidence concerns the gene PGP and preeclampsia.