Table showing safety of drugs in pregnancy and lactation (Drugs starting with M)
| Drug | Pregnancy category | Use during lactation |
| Magaldrate | C | |
| Magnesium carbonate | B | |
| Magnesium chloride | Use with caution | |
| Magnesium hydroxide | B | Safe |
| Magnesium sulfate | B | Safe |
| Malathion | B (topical use) | |
| Mannitol | C | Safe |
| Maprotiline | B | |
| Mebendazole | C | Safe |
| Mebeverine | B | Use with caution |
| Meclozine | B | |
| Medroxyprogesterone | X | Safe after 6 month of the infant |
| Mefenamic acid | C | Safe |
| Mefloquine | B | Safe |
| Meloxicam | C | Use with caution |
| Melphalan | D | |
| Mercaptopurine | D | Unsafe |
| Meropenem | B | Safe |
| Mesalazine | C | Safe |
| Mesna | B | Unsafe |
| Mestranol | B | Unsafe |
| Metformin | C | Safe |
| Methimazole | D | |
| Methotrexate | X | Unsafe |
| Methoxsalen | B | Unsafe |
| Methyldopa | B | Safe |
| Methylprednisolone | C (topical use) | Safe(topical use) |
| Methysergide | C | Unsafe |
| Metoclopramide | B | Safe |
| Metoprolol | C | Safe |
| Metronidazole | B | Safe |
| Metyrapone | B | Use with caution |
| Miconazole | C | Safe |
| Midazolam | C | Safe in single dose |
| Mifepristone | X | |
| Minocycline | D | Unsafe |
| Minoxidil | C | Safe(topical use)Use with caution(oral use) |
| Misoprostol | X | Use with caution |
| Mometasone furoate | B | Safe |
| Montelukast | B | Use with caution |
| Morphine | C,D if prolonged use or high doses at term | Safe in usual dose,use with caution if high dose |
| Moxifloxacin | B | Use with caution |
| Mupirocin | B | Safe
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