Drugs that Require Frequent Monitoring

Drug

Therapeutic and Toxic Levels
Therapeutic: 1-30 mcg/ml
Toxic: >200 mcg/ml
Acetaminophen
Contraindicated in:
(Tylenol)
Liver disease
Side Effects of Toxicity:
Hepatic Necrosis
Therapeutic Level: 100 mcg/ml
Alcohol (Ethanol)
Toxic: >400 mcg/ml
Therapeutic: 120-250 mcg/ml
Toxic: >500 mcg/ml
Contraindicated in: Narrow-angle glaucoma and potential fatal reactions when used with MAO inhibitors
Amitriptyline
Side Effects of Toxicity:
(Elavil)
Drowsiness, sedation, lethary, fatigue, dry mouth and eyes, blurred vision, hypotension, and tachycardia.
Caution patients to use a sun screen.
Therapeutic effects within 2 to 6 weeks of initiating therapy.
Therapeutic: 8-12 mcg/ml
Toxic: >15 mcg/ml
Contraindicated in:
Carbamazepine
Bone marrow depression
(Tegretol)
Side Effects of Toxicity:
Drowsiness, dizziness, and ataxia.
Caution patients to use a sun screen and to carry a medical alert card. Therapeutic: 700-1000 mcg/ml
Toxic: >5000 mcg/ml
Contraindicated in:
Chlordiazepoxide Comatose patients with CNS depression, narrow-angle glaucoma
(Librium)
Side Effects of Toxicity:
Drowsiness and dizziness.
Alcohol Withdrawal Treatment: Assess patients for signs and symptoms of delirium tremors (DTs).
Desopyramide
Therapeutic: Variable
(Norpace)
Toxic: >7 mcg/ml

Diazepam
(Valium)

Digitoxin

Digoxin

Doxepin

Glucocorticoids

Contraindicated in:
Cardiogenic shock, 2nd and 3rd degree heart blocks, sick sinus syndrome Side Effects of Toxicity:
Signs and symptoms of congestive heart failure.
Therapeutic: 100-1000 mcg/ml
Toxic: >5000 mcg/ml
Contraindicated in:
Comatose patients with CNS depression, narrow-angle glaucoma
Side Effects of Toxicity:
Sedation with ataxia, dizziness, and slurred speech.
Therapeutic effects within 1 to 2 weeks of initiating therapy.
Therapeutic: 20-35 ng/ml
Toxic: >45 ng/ml
Contraindicated in:
Uncontrolled ventricular arrhythmias, AV block
Side Effects of Toxicity:
Abdominal pain, anorexia, nausea, vomiting, visual disturbances, bradycardia, and other arrhythmias.
Therapeutic: 0.8-1.5 mcg/ml
Toxic: >2 mcg/ml
Contraindicated in:
Uncontrolled ventricular arrhythmias, AV block
Side Effects of Toxicity:
Abdominal pain, anorexia, nausea, vomiting, visual disturbances, bradycardia, and other arrhythmias.
Therapeutic: 30-150 mcg/ml
Toxic: >500 mcg/ml
Contraindicated in:
Narrow-angle glaucoma
Side Effects of Toxicity:
Sedation, fatigue, blurred vision, hypotension, dry mouth, and constipation. Caution patients to use a sun screen.
May cause hypotension, tachycardia, and potentially fatal reactions when used with MAO inhibitors
Therapeutic effects within 2 to 6 weeks of initiating therapy.
Contraindicated in:
Serious infections
Signs of adrenal insufficiency: Hypotension, weight loss,

Imipramine
(Tofranil)

Lithium

Lidocaine
(Xylocaine)

weakness, nausea, vomiting, anorexia, lethargy, confusion, restlessness. Side Effects:
Depression or euphoria, personality changes, hypertension, decreased wound healing, petechiae, ecchymoses, hyperglycemia, hypokalemia, hypernatremia, fluid retention, aseptic necrosis of joints, osteoporosis, cushingoid appearance (moon face, and buffalo hump)
Monitor blood sugars, BUN, creatinine.
Advise patients that medication should NOT be abruptly discontinued by tapered off over 2 to 4 weeks.
Therapeutic: 125-250 mcg/ml
Toxic: >500 mcg/ml
Contraindicated in:
Narrow-angle glaucoma
Side Effects of Toxicity:
Disturbed concentration, confusion, restlessness, agitation, convulsions, drowsiness, mydriasis, arrhythmias, fever, hallucinations, vomiting, and dyspnea.
Caution patients to use a sun screen.
Therapeutic effects within 2 to 6 weeks of initiating therapy.
Therapeutic: 0.6-1.2 mcg/ml
Toxic: >2 mcg/ml
Serum levels should be monitored twice weekly during initiation of therapy and every 2 to 3 months durgin chronic therapy.