Hi!
I got this list from the American association of family physicians site- antibiotics were not on there.
If you want to read the entire (long article) here is a link:
http://familydoctor.org/x6532.xml
Medications that May Cause Weight Gain
Condition Medication
Allergies Antihistamines (such as Claritin, Allegra)
High blood pressure Alpha blockers (such as Hytrin, Cardura)
Beta blockers (such as Betapace, Blocadren, Tenormin)
Methyldopa (Aldoment)
Contraception Progestins (a component of certain oral contraceptives, such as Lo/Ovral and Ortho-Tri-Cylcen)
Depression Tricyclic antidepressants (such as Norpramin and Sinequan)
Diabetes Insulin
Sulfonylureas (such as Diabinese and Glucotrol)
Epilepsy Valproate (such as Depakene)
Manic-depressive illness Lithium (such as Eskalith and Lithobid)
Schizophrenia Neuroleptics (such as Zyprexa and Risperdal)