Active substances

2,443 active substances of the UK medicines whose patient leaflet or SPC is on this site, from A to Z – with the number of medicines containing the substance alone or in a combination with other substances.

• Macrogol 4000 4 medicines: 3 alone · 1 in combination
• Magnesium acetate tetrahydrate 7 medicines: 2 alone · 5 in combination
• Magnesium alginate 1 medicine: 1 in combination
• Magnesium aspartate 3 medicines: 3 alone
• Magnesium carbonate 6 medicines: 6 in combination
• Magnesium carbonate heavy 3 medicines: 1 alone · 2 in combination
• Magnesium carbonate light 2 medicines: 2 in combination
• Magnesium chloride 3 medicines: 2 alone · 1 in combination
• Magnesium chloride hexahydrate 30 medicines: 5 alone · 25 in combination
• Magnesium hydroxide 11 medicines: 5 alone · 6 in combination
• Magnesium oxide light 1 medicine: 1 in combination
• Magnesium sulfate 5 medicines: 4 alone · 1 in combination
• Magnesium sulfate dried 2 medicines: 2 in combination
• Magnesium sulfate heptahydrate 15 medicines: 10 alone · 5 in combination
• Magnesium trisilicate 5 medicines: 1 alone · 4 in combination
• Mangafodipir trisodium 1 medicine: 1 alone
• Manganese 1 medicine: 1 in combination
• Manganese chloride 2 medicines: 2 in combination
• Manganese chloride tetrahydrate 2 medicines: 2 in combination
• Manganese gluconate 1 medicine: 1 in combination
• Manganese glycerophosphate 1 medicine: 1 in combination
• Mannitol 9 medicines: 6 alone · 3 in combination
• Maralixibat 1 medicine: 1 alone
• Maraviroc 8 medicines: 8 alone
• Maribavir 1 medicine: 1 alone
• Maropitant 1 medicine: 1 alone
• Maropitant citrate 1 medicine: 1 alone
• Marshmallow root 1 medicine: 1 in combination
• Marstacimab 2 medicines: 2 alone
• Masitinib mesilate 1 medicine: 1 alone
• Mavacamten 4 medicines: 4 alone
• Mavacoxib 1 medicine: 1 alone
• Maximum three of the following purified, inactivated foot-and-mouth disease virus strains: O1 Manisa ≥ 6 PD50* 1 medicine: 1 in combination
• Measles virus Enders’ Edmonston strain (live, attenuated), mumps virus Jeryl Lynn (level B) strain (live, attenuated), rubella virus Wistar RA 27/3 strain (live, attenuated) 1 medicine: 1 alone
• Mebendazole 6 medicines: 6 alone
• Mebeverine 19 medicines: 18 alone · 1 in combination
• Mecasermin 2 medicines: 2 alone
• Meclozine 2 medicines: 2 alone
• MEDIUM CHAIN TRIGLYCERIDES 10 medicines: 10 in combination
• Medroxyprogesterone 25 medicines: 20 alone · 5 in combination
• Mefenamic acid 10 medicines: 10 alone
• Mefloquine 1 medicine: 1 alone
• Megestrol 2 medicines: 2 alone
• Meglumine amidotrizoate 2 medicines: 2 in combination
• Meglumine gadobenate 2 medicines: 2 alone
• Meglumine gadopentetate 1 medicine: 1 alone
• Melaleuca oil 1 medicine: 1 in combination
• Melatonin 57 medicines: 57 alone
• Meloxicam 25 medicines: 23 alone · 2 in combination
• Melphalan 5 medicines: 5 alone
• Memantine 65 medicines: 65 alone
• Menadiol 1 medicine: 1 alone
• Meningococcal group A, C, W-135 and Y conjugate vaccine 1 medicine: 1 alone
• Meningococcal group B vaccine 1 medicine: 1 alone
• Meningococcal group C vaccine 1 medicine: 1 alone
• Meningococcal groups A + C + W135 + Y vaccine 1 medicine: 1 alone
• Menotrophin 9 medicines: 9 alone
• Menthol 23 medicines: 2 alone · 21 in combination
• Menthol + Peppermint 1 medicine: 1 alone
• Menthone 1 medicine: 1 in combination
• Mepivacaine 3 medicines: 3 alone
• Mepolizumab 4 medicines: 4 alone
• Meptazinol 2 medicines: 2 alone
• Mepyramine 5 medicines: 4 alone · 1 in combination
• Mercaptamine 8 medicines: 8 alone
• Mercaptopurine 7 medicines: 7 alone
• Meropenem 22 medicines: 21 alone · 1 in combination
• Mertiatide 1 medicine: 1 alone
• Mesalazine 43 medicines: 43 alone
• Mesna 5 medicines: 5 alone
• Mesterolone 1 medicine: 1 alone
• Mestranol 1 medicine: 1 in combination
• Metaflumizone 1 medicine: 1 alone
• metaflumizone, amitraz 1 medicine: 1 alone
• Metaraminol 5 medicines: 5 alone
• Metformin 190 medicines: 122 alone · 68 in combination
• Methacholine 1 medicine: 1 alone
• Methadone 22 medicines: 22 alone
• Methenamine 2 medicines: 2 alone
• Methocarbamol 8 medicines: 8 alone
• Methotrexate 66 medicines: 66 alone
• Methoxsalen 3 medicines: 3 alone
• Methoxy polyethylene glycol-epoetin beta 10 medicines: 10 alone
• Methoxyflurane 1 medicine: 1 alone
• Methyl aminolevulinate 1 medicine: 1 alone
• Methyl nicotinate 5 medicines: 1 alone · 4 in combination
• Methyl salicylate 17 medicines: 2 alone · 15 in combination
• Methyldopa 17 medicines: 17 alone
• Methylnaltrexone bromide 4 medicines: 4 alone
• Methylphenidate 105 medicines: 105 alone
• Methylprednisolone 8 medicines: 6 alone · 2 in combination
• Methylprednisolone acetate 5 medicines: 5 alone
• Methylprednisolone sodium succinate 9 medicines: 9 alone
• Methylthioninium chloride 4 medicines: 4 alone
• Metoclopramide 18 medicines: 16 alone · 2 in combination
• Metolazone 2 medicines: 2 alone
• Metoprolol 10 medicines: 10 alone
• Metreleptin 3 medicines: 3 alone
• Metronidazole 44 medicines: 42 alone · 2 in combination
• Metyrapone 2 medicines: 2 alone

Sources: the MHRA product information, the European Medicines Agency and the NHS Dictionary of Medicines and Devices (dm+d), NHS Business Services Authority.