High BP and Antihistamines

My brother is asthmatic, has allergy. My brother, myself and my dad all of us have high BP and are on medications. I remember to have read that some antihistamines increase BP.
So the question is which antihistamine, asthmatic drug can he take.
His doctor has prescribed cetrizine ( cetrizine di hydrochloride ) and I'm not asthmatic , but have allergy and I was told I could use claritin ( loratadine ). Which is better for my brother, so that asthma - allergy medication doesn't retard the effect of the BP medication.

Should he take cetrizine or claritin along with BP medication.

Your help is very much appreciated.
Thanks,

[Cleveland Clinic, MD]

Antihistamines aren't so much a problem as decongestants.  Certain decongestants (e.g. psedoepedrine, phenylephrine) increase the blood pressure and should be avoided by persons with high blood pressure.  Of course he should check with his doctor before taking any medication if he is already taking other medications.