- O-CAL F.A. (Multivitamin With Minerals)
- O-Cal Prenatal (Multivitamin, Prenatal)
- Oasis Tears
- Oasis Tears Plus
- OB Complete (Multivitamin, Prenatal)
- OB Complete 400
- OB Natal One
- Ob-20 (Multivitamin, Prenatal)
- Obtrex DHA
- Oby-Cap (Phentermine)
- Occlusal-HP (Salicylic Acid Topical)
- Ocella
- Octreotide
- Ocucoat PF (Ocular Lubricant)
- Oyster Calcium (Calcium Carbonate)
- Oyster-D (Calcium Vitamin D)
- Oyster Shell (Calcium Carbonate)
- Oystercal-D (Calcium Vitamin D)
- Oyster Shell Calcium with Vitamin D (Calcium Vitamin D)
- OxyContin (Oxycodone)
- Oxycodone
- Oxybutynin
- Oxyfast (Oxycodone)
- Oxymetazoline Nasal
- Oxymetazoline Ophthalmic
- OxyIR (Oxycodone)
- Oxymetholone
- Oysco 500 (Calcium Carbonate)
- Oxytrol (Oxybutynin)
- Oxytocin
- Oxymorphone
- Oyst-Cal-D (Calcium Vitamin D)
- Oyst Cal 500 (Calcium Carbonate)
- Oysco D (Calcium Vitamin D)
- Oysco 500 with D (Calcium Vitamin D)
- Oyster Cal (Calcium Carbonate)
- Oxy Balance Deep Pore Cleansing, Gentle (Salicylic Acid Topical)
- Oxy Daily Wash
- Oxy Daily Wash Chill Factor (Benzoyl Peroxide Topical)
- Oxy Face Scrub Chill Factor (Salicylic Acid Topical)
- Oxy-10 (Benzoyl Peroxide Topical)
- Oxistat (Oxiconazole Topical)
- Oxsoralen-Ultra (Methoxsalen)
- Oxy 10 Balance (Benzoyl Peroxide Topical)
- Oxy Balance (Benzoyl Peroxide Topical)
- Oxy Balance Daily Cleaning, Normal Skin (Salicylic Acid Topical)
- Oxaprozin
- Oxazepam
- Oxcarbazepine
- Oxiconazole Topical
- Oxipor VHC (Coal Tar Topical)
- Oxandrin (Oxandrolone)
- Oxaliplatin
- Oxacillin
- Ovidrel (Chorionic Gonadotropin (Hcg))
- Ovace Plus
- Ovcon 35 (Ethinyl Estradiol Norethindrone)
- Ovcon 35 Fe (Ethinyl Estradiol Norethindrone)
- Ovcon 50 (Ethinyl Estradiol Norethindrone)
- Ovide (Malathion Topical)
- Otirx (Chloroxylenol/Hydrocortisone/Pramoxine Otic)
- Otomar HC (Chloroxylenol/Hydrocortisone/Pramoxine Otic)
- Oto-End
- Outgro Pain Relief (Benzocaine Topical)
- Oxandrolone
- OTC pain medications: guides users should know
- Octostim (Desmopressin acetate) Drug
- Olanzapine Sandoz (olanzapine film-coated tablets) Drug
- Olanzapine Sandoz ODT (Olanzapine orally disintegrating tablets) Drug
- Olmetec (Olmesartan medoxomil) Drug
- Olmetec Plus (Olmesartan medoxomil and hydrochlorothiazide) Drug
- Omacor (Omega-3-acid ethyl esters 90) Drug
- Omepral (Omeprazole magnesium) Drug
- Omeprazole Sandoz (omeprazole enteric capsules) Drug
- Omeprazole Sandoz Tablets (omeprazole enteric-coated tablets) Drug
- Omeprazole Winthrop (omeprazole) Drug
- Omnitrope (Somatropin) Drug
- Onbrez Breezhaler (Indacaterol maleate) Drug
- Oncotice (Bacillus Calmette and Guerin) Drug
- Ondansetron Alphapharm (ondansetron hydrochloride dihydrate) Drug
- Ondansetron Injection Drug
- Ondansetron Tabs Pfizer (Ondansetron) Drug
- Ondaz (ondansetron hydrochloride dihydrate tablets) Drug
- Ondaz Zydis (ondansetron wafers) Drug
- Onglyza (Saxagliptin) Drug
- Ordine (Morphine hydrochloride) Drug
- Orencia (Abatacept Powder for intravenous infusion; Abatacept solution for Injection) Drug
- Orgalutran (Ganirelix 250 micrograms in 0.5 millilitres) Drug
- Orgaran (Danaparoid sodium) Drug
- Orudis Gel (Ketoprofen) Drug
- Orudis SR (Ketoprofen) Drug
- Orudis Suppositories (Ketoprofen) Drug
- Oruvail SR (Ketoprofen) Drug
- Otodex (Framycetin sulfate , Gramicidin , Dexamethasone) Drug
- Ovestin Cream (Oestriol 0.1%) Drug
- Ovestin Ovula (Oestriol 0.5 mg per pessary) Drug
- Ovestin Tablets (Oestriol 1 mg) Drug
- Ovidrel (Choriogonadotropin alfa) Drug
- Ovidrel Pen (Choriogonadotropin alfa) Drug
- Oxaliplatin Alphapharm (oxaliplatin) Drug
- Oxis (Eformoterol fumarate dihydrate for inhalation.) Drug
- Oxybuprocaine Minims (Oxybuprocaine hydrochloride Eye Drops) Drug
- Oxybutynin Sandoz (oxybutynin hydrochloride tablets) Drug
- Oxybutynin Winthrop (Oxybutynin Hydrochloride) Drug
- OxyContin (Oxycodone hydrochloride) Drug
- OxyNorm capsules (Oxycodone hydrochloride) Drug
- OxyNorm injection (Oxycodone hydrochloride) Drug
- OxyNorm liquid (Oxycodone hydrochloride) Drug
- Oxytocin Sandoz (synthetic oxytocin) Drug
- Oxytrol (Oxybutynin) Drug
- Ozole (Fluconazole Capsules) Drug
- Ozole 150mg (Fluconazole 150 mg Capsule) Drug
