| Omesar Plus 20 mg/12.5 mg & 20 mg/25 mg Film-coated tablets | - |  27/03/19 |  27/03/19 | Hydrochlorothiazide, olmesartan medoxomil | A. Menarini Pharmaceuticals Ireland Ltd |
| Omesar Plus 40 mg/12.5 mg & 40 mg/25 mg film-coated tablets | - | 27/03/19 | 27/03/19 | Hydrochlorothiazide, olmesartan medoxomil | A. Menarini Pharmaceuticals Ireland Ltd |
| Omnexel | - | 15/07/15 | 21/07/15 | Tamsulosin Hydrochloride | Astellas Pharma Co. Ltd |
| Onbrez Breezhaler 150 microgram inhalation powder, hard capsules | - | 18/12/19 | 18/12/19 | Indacaterol maleate | Novartis Ireland Limited |
| Onbrez Breezhaler 300 microgram inhalation powder, hard capsules | - | 18/12/19 | 18/12/19 | Indacaterol maleate | Novartis Ireland Limited |
| Oncaspar (solution) | | 20/05/19 | 20/05/19 | pegaspargase | Servier Laboratories Ireland Ltd |
| Oncaspar 750 U/ml powder for solution for injection/infusion | | 03/10/19 | 03/10/19 | pegaspargase | Servier Laboratories Ireland Ltd |
| Ondansetron 2mg/ml Solution for Injection or Infusion | - | 12/12/19 | 12/12/19 | Ondansetron hydrochloride dihydrate | Gerard Laboratories |
| One-Alpha 0.25 mcg Capsules | - | 28/10/16 | 24/11/17 | Alfacalcidol | LEO Pharma |
| One-Alpha 1 mcg Capsules | - | 28/10/16 | 16/02/17 | Alfacalcidol | LEO Pharma |
| One-Alpha Drops | - | 17/05/19 | 26/04/19 | Alfacalcidol | LEO Pharma |
| Onglyza 2.5 mg & 5 mg film-coated tablets | - | 24/08/18 | 23/08/18 | Saxagliptin hydrochloride | AstraZeneca Pharmaceuticals (Ireland) DAC |
| Opatanol 1mg/ml eye drops solution | - | 11/12/19 | 08/04/19 | Olopatadine (as hydrochloride) | Novartis Ireland Limited |
| OPDIVO 10 mg/mL concentrate for solution for infusion | | 09/01/20 | 09/01/20 | Nivolumab | Bristol-Myers Squibb Pharma EEIG |
| Opsumit 10mg | - | 06/12/18 | 05/10/18 | Macitentan | Actelion, a division of Janssen-Cilag International NV |
| Opticrom 2% w/v Eye Drops Solution | - | 12/12/16 | 07/08/17 | Sodium Cromoglicate | SANOFI |
| Opticrom Allergy 2%w/v Eye Drops, Solution | - | 14/03/18 | 11/12/18 | Sodium Cromoglicate | SANOFI |
| Opticrom Allergy Single Dose 2%w/v Eye Drops, solution | - | 11/05/17 | 27/11/19 | Sodium Cromoglicate | SANOFI |
| Optrex Clear Eyes Eye Drops | - | 15/01/20 | 19/01/18 | Hamamelis, Naphazoline Hydrochloride | Reckitt Benckiser Ireland Limited |
| Oraldene 0.1% w/v Gargle / Mouthwash | - | 03/04/19 | 03/04/19 | Hexetidine | Johnson & Johnson (Ireland) Ltd |
| Oraldene Icemint 0.1% w/v Gargle / Mouthwash | - | 03/04/19 | 03/04/19 | Hexetidine | Johnson & Johnson (Ireland) Ltd |
| Oramorph Concentrated Oral Solution | - | 25/04/19 | 05/04/19 | Morphine sulfate | Boehringer Ingelheim Limited |
| Oramorph Oral Solution | - | 25/04/19 | 05/04/19 | Morphine sulfate | Boehringer Ingelheim Limited |
| ORENCIA 125 mg solution for injection in pre-filled pen | - | 13/01/20 | 16/12/19 | Abatacept | Bristol-Myers Squibb Pharma EEIG |
| ORENCIA 250 mg powder for concentrate for solution for infusion | - | 13/01/20 | 16/12/19 | Abatacept | Bristol-Myers Squibb Pharma EEIG |
