Toxic Drug Monitoring
DEFINITION OF TERMS:
- Pharmacodynamics: what the drugs do to the body
- Pharmacokinetics: what the body does to the drug (biotransformation, distribution, metabolism and elimination)
- First pass metabolism: drugs enter the hepatic route first before entering the general circulation
- Half-life: time needed for a drug’s concentration in serum to decrease into
half - Peak specimen: collection of this is done 30-60 mins after the administration of drug
- Trough specimen: this is collected before administration of the succeeding dose
| CLASSIFICATION OF DRUGS | REPRESENTATIVE DRUGS |
| Antibiotics | Aminoglycosides, chloramphenicol, vancomycin |
| Anticonvulsants | Ethosuximide, Carbamazepine, Phenytoin, Phenobarbital, Valproic acid |
| Antidepressants | Lithium, Fluoxetine and tricyclic antidepressants |
| Anti inflammatory/analgesics | Aspirin, acetaminophen |
| Anti-neoplastic | Busulfan, methotrexate |
| Bronchodilators | Theohylline |
| Cardioactive | Digoxin, Procainamide, Lidocaine, Propanolol, Quinidine |
| Immunosuppressives | Tacrolimus (FK-506), Prednisone, Cyclosporine |
GOOD TO KNOW FOR THE DRUGS:
- Aspirin: drug that inhibits cyclooxygenase
- Acetaminophen: hepatotoxic drug
- Lithium: for treatment of bipolar disorder or manic depression
- Phenobarbital: used for treatment of grand-mal
- Valproic acid: for treatment of petit mal
- Vancomycin: cause of red man syndrome
| CONVERSION FACTORS | ||
| ANALYTES | CONVENTIONAL UNITS TO SI UNITS | CONVERSION FACTOR |
| ALBUMIN | g/dL to g/L | 10 |
| PHOSPHOLIPID | 0.01 | |
| TOTAL PROTEIN | 10 | |
| AMMONIA | μg/dL to μmol/L | 0.587 |
| THYROXINE | μg/dL to nmol/L | 12.9 |
| BICARBONATE | mEq/L to mmol/L | 1.0 |
| CHLORIDE | 1.0 | |
| MAGNESIUM | 0.5 | |
| POTASSIUM | 1.0 | |
| SODIUM | 1.0 | |
| LITHIUM | mEq/L to μmol/L | 1.0 |
| BUN | mg/dL to mmol/L | 0.357 |
| CALCIUM | 0.25 | |
| CHOLESTEROL | 0.026 | |
| GLUCOSE | 0.0555 | |
| PHOSPHORUS | 0.323 | |
| TRIGLYCERIDE | 0.0113 | |
| URIC ACID | 0.0595 | |
| BILIRUBIN | mg/dL to μmol/L | 17.1 |
| CREATININE | 88.4 | |
| IRON | 0.179 | |
| pCO2 | mm/Hg to kPa | 0.133 |
| pO2 | 0.133 | |
