Drugs with a Narrow Therapeutic Index Chart
| Drug | Therapeutic Range | Toxic Range |
|---|---|---|
| Carbamazepine Tegretol | 4-12 mg/L | >30 mg/L |
| Cyclosporine Neoral, Sandimmune | 100-400 ng/ml *12 hours after dose | |
| Digoxin Lanoxin | 0.5-1 ng/ml CHF 0.8-2 ng/ml Arrhythmias | *Toxic levels can overlap between therapeutic and toxic ranges. Assess for signs & symptoms of toxicity |
| Ethosuximide Zarontin | 40-100 mcg/ml | >150 mcg/ml |
| Levothyroxine Synthroid, Levoxyl | Normal TSH level | Directly related to T4 levels |
| Lithium | 0.6-1.2 mEq/L | >1.5 mEq/L |
| Phenytoin Dilantin | 10-20 mcg/ml | >20 mcg/ml >100 mcg/ml Lethal |
| Procainamide Pronestyl, Procan | 10-20 mcg/ml | > 40 mcg/ml |
| Tacrolimus Prograf | 5-20 ng/ml | |
| Theophylline Elixophyllin, Theo-24, Theochron, Uniphyl | 5-15 mpg/ml | > 20 mpg/ml |
| Warfarin Coumadin, Jantoven | INR 2.0-3.0 INR 2.5-3.5 for mechanical prosthetic heart valve | INR >3.0 |