| Drug |
Pregnancy category |
Use during lactation |
| Oestradiol |
B |
Unsafe, lactation may be suppressed |
| Oestriol |
B |
Use with caution, lactation may be suppressed |
| Oestrogens, conjugated |
D |
Unsafe, lactation may be suppressed |
| Ofloxacin |
C |
|
| Olanzapine |
B |
Safe |
| Olmesartan |
D |
Unsafe |
| Olsalazine |
C |
Safe |
| Omeprazole |
B |
Safe |
| Ondansetron |
B |
Use with caution |
| Oral rehydration solution |
|
Safe |
| Orphenadrine |
B |
Use with caution |
| Oseltamivir |
B |
Safe |
| Oxacillin |
B |
|
| Oxazepam |
C |
Safe, caution in chronic use, infant may have drowsiness |
| Oxybutynin |
B |
Use with caution |
| Oxymetazoline |
C |
Safe |
| Oxytocin |
X |
|
