| Sofosbuvir Action Pathway |  | Drug Action | Magnesium cation / Zinc / Sofosbuvir |
| Solifenacin M3 Bladder Muscle Relaxation Action Pathway |  | Drug Action | Calcium / Magnesium cation / Solifenacin |
| Solriamfetol Action Pathway |  | Drug Action | Pyridoxal phosphate / Ascorbic acid / Tyrosine / ATP / Norepinephrine / Dopamine / Levodopa / Calcium / Magnesium cation / Iron / Cyclic adenosine monophosphate / Pyrroloquinoline Quinone / Pyrophosphoric acid / Solriamfetol |
| Solriamfetol Predicted Metabolism Pathway |  | Metabolic | Mesoheme / Solriamfetol |
| Sonidegib Drug Metabolism |  | Metabolic | Sonidegib |
| Sorafenib Action Pathway |  | Drug Action | Sorafenib / Magnesium cation / Zinc |
| Sorafenib Metabolism Pathway (old) |  | Drug Metabolism | Sorafenib / Mesoheme / Uridine-5'-Diphosphate |
| Sotalol Action Pathway |  | Drug Action | ATP / Sotalol / Potassium cation / Calcium |
| Sotalol Action Pathway (New) |  | Drug Action | ATP / Sotalol / Potassium cation / Calcium |
| Sotalol Predicted Metabolism Pathway |  | Metabolic | Sotalol / Mesoheme |
| Spectinomycin Action Pathway |  | Drug Action | Spectinomycin |
| Spectinomycin Anti-bacterial Action Pathway |  | Drug Action | Spectinomycin |
| Spectinomycin Drug Metabolism |  | Metabolic | Spectinomycin |
| Spermidine and Spermine Biosynthesis |  | Metabolic | Pyridoxal phosphate / Ademetionine / Spermine / Ornithine / Methionine / ATP / Potassium cation / Magnesium cation / Putrescine / Spermidine / Pyruvaldehyde / Pyrophosphoric acid |
| Sphingolipid Metabolism |  | Metabolic | Pyridoxal phosphate / Serine / ATP / Calcium / Magnesium cation / Zinc / Uridine diphosphate glucose / Hexadecanal / Uridine-5'-Diphosphate / N,N,N-Trimethyl-2-(phosphonooxy)ethanaminium |
| Sphingolipid Signaling |  | Signaling | Serine / Calcium / Magnesium cation |
| Sphingolipid Signaling (Receptor) |  | Signaling | Nitric Oxide / Calcium / Magnesium cation |
| Spirapril Action Pathway |  | Drug Action | Potassium cation / Spirapril / Zinc |
| Spirapril Metabolism Pathway |  | Drug Metabolism | Spirapril / Zinc |
| Spironolactone Action Pathway |  | Drug Action | Cysteine / Spironolactone / Potassium cation / Urea |
| Spironolactone Action Pathway (New) |  | Drug Action | Spironolactone / Potassium cation / Urea |
| Stanozolol Drug Metabolism |  | Metabolic | Stanozolol |
| Starch and Sucrose Metabolism |  | Metabolic | Pyridoxal phosphate / NADH / ATP / Calcium / Magnesium cation / Uridine diphosphate glucose / Maltose / Uridine-5'-Diphosphate / Pyrophosphoric acid / Fructose |
| Stavudine Action Pathway |  | Drug Action | Stavudine |
| Stavudine Drug Metabolism |  | Metabolic | Stavudine |