List of medicines that should be stopped one week before:

Antihistamines:
azatadine (Optimine)
brompheniramine (Bromphen, Dimeptapp)
** cetirizine (Zyrtec)
chlorpheniramine (Chlor-Trimeton)
clemastine (Tavist, Antihist)
cyproheptadine (Periactin)
** diphenhydramine (Benadryl, Sominex, Temaril)
** fexofenadine (Allegra)
** hydroxyzine (Atarax, Vistaril)
** loratadine (Claritin)
promethazine (Phenergan)
tripelennamine (PBZ)
** Most over the counter cough/cold/flu medicines

Leukotriene Modifiers: (Hold for 2-3 days):
zafirlukast (Accolate)
** montelukast (Singulair)
zileuton (Zyflo)
 

Reflux Meds: (hold for 3 days)
cimetidine (Tagamet)
famotidine (Pepcid)
nizatidine (Axid)
ranitidine (Zantac)

Anti-Vomiting/Nausea/Dizzy:
prochlorperazine (Compazine)
meclizine (Antivert)

Antidepressants/Anxiety (try to hold for 2 weeks if possible - but DO NOT STOP without asking prescribing doctor first,    CONTINUE if any doubt - we can still do testing in most cases).
alprazolam (Xanax)
amitriptyline (Elavil)
clonazepam (Klonopin)
clomipramine (Anafranil)
desipramine (Norpramin)
doxepin (Sinequan)
imipramine (Tofranil)
nortriptyline (Pamelor)
citalopram (Celexa)
nefazodone (Serzone)
venlafaxine (Effexor)

Antipsychotics: (DO NOT STOP WITHOUT permission from prescribing doctor)
chlorpromazine (Thorazine)
haloperidol (Haldol) 

MEDS THAT ARE OKAY to CONTINUE: (take as usual)
Tylenol (acetaminophen) or Motrin (ibuprofen)
ALL antibiotics or antifungals or Probotics
sudafed (pseudoephedrine)
guaifenesin
dextrometorphan
Prilosec/Nexium/Protonix/Aciphex