| Maprotiline H1 Antihistamine Neurological Sleep Action Pathway |  | Drug Action | Pyridoxal phosphate / Histidine / Maprotiline / Calcium |
| Maraviroc Action Pathway |  | Drug Action | Magnesium cation / Maraviroc |
| Maraviroc Predicted Metabolism Pathway |  | Metabolic | Mesoheme / Maraviroc |
| Maribavir Action Pathway |  | Drug Action | Maribavir |
| Mazindol Dopamine Reuptake Inhibitor Action Pathway |  | Drug Action | Pyridoxal phosphate / Tyrosine / ATP / Mazindol / Dopamine / Levodopa / Calcium / Magnesium cation / Iron / Cyclic adenosine monophosphate |
| Mazindol Drug Metabolism |  | Metabolic | Mazindol |
| Mebendazole Action Pathway |  | Drug Action | ATP / Mebendazole / Magnesium cation |
| Mebhydrolin H1-Antihistamine Action |  | Drug Action | Calcium / Mebhydrolin |
| Mebrofenin Predicted Metabolism Pathway |  | Metabolic | Mesoheme / Mebrofenin |
| Mecamylamine Drug Metabolism |  | Metabolic | Mecamylamine |
| Mechanisms of Fibrosis |  | Signaling | Magnesium cation |
| Mechlorethamine Action Pathway (New) |  | Drug Action | Adenine / Mechlorethamine |
| Mechlorethamine Predicted Metabolism Pathway |  | Metabolic | Mechlorethamine / Mesoheme |
| Meclizine H1 Antihistamine Smooth Muscle Relaxation Action Pathway |  | Drug Action | Meclizine / Calcium / Magnesium cation |
| Meclizine H1-Antihistamine Action |  | Drug Action | Meclizine / Calcium |
| Meclizine H1-Antihistamine Blood Vessel Constriction Action Pathway |  | Drug Action | Arginine / Citrulline / Sapropterin / Nitric Oxide / Meclizine / Calcium / Magnesium cation / Mesoheme / Flavin adenine dinucleotide / Flavin mononucleotide |
| Meclizine H1-Antihistamine Immune Response Action Pathway |  | Drug Action | Meclizine / Calcium |
| Meclofenamic acid Action Pathway |  | Drug Action | Glutathione / Dinoprostone / Meclofenamic acid / Calcium / Mesoheme / Prostaglandin G2 / Arachidonic Acid |
| Medifoxamine Predicted Metabolism Pathway |  | Metabolic | Mesoheme / Medifoxamine |
| Medium Chain Acyl-CoA Dehydrogenase Deficiency (MCAD) |  | Disease | Adenosine phosphate / NADH / ATP / Levocarnitine / Magnesium cation / Flavin adenine dinucleotide / Palmitic Acid / Pyrophosphoric acid |
| Medium Chain Acyl-CoA Dehydrogenase Deficiency (MCAD) |  | Disease | Adenosine phosphate / NADH / ATP / Levocarnitine / Magnesium cation / Flavin adenine dinucleotide / Palmitic Acid / Pyrophosphoric acid |
| Medrogestone Drug Metabolism |  | Metabolic | Medrogestone |
| Medronic acid Drug Metabolism |  | Metabolic | Medronic acid |
| Medrysone Action Pathway |  | Drug Action | Glutathione / Medrysone / Dinoprostone / Calcium / Prostaglandin D2 / Mesoheme / Prostaglandin G2 / Arachidonic Acid |
| Medrysone Predicted Metabolism Pathway |  | Metabolic | Medrysone / Mesoheme |