Lab Values & Drug Monitoring Flashcards
carbamazepine
4-12 mcg/mL
digoxin
- 8-2 ng/mL (Afib)
0. 5-0.9 ng/mL (HF)
gentamicin (traditional dosing)
Peak: 5-10 mcg/mL
Trough: < 2 mcg/mL
lithium
0.6-1.2 mEq/L (up to 1.5 mEq/L for acute symptoms), drawn as trough
phenytoin/fosphenytoin
10-20 mcg/mL; if albumin is low, correct serum level
Free Phenytoin
1-2.5 mcg/mL
procainamide
4-10 mcg/mL
NAPA (procainamide active metabolite)
15-25 mcg/mL
procainamide + NAPA (combined)
10-30 mcg/mL
theophylline
5-15 mcg/mL
tobramycin (traditional dosing)
peak: 5-10 mcg/mL
trough: < 2 mcg/mL
valproic acid (VPA)
50-100 mcg/mL (up to 150 mcg/mL in some patients); if albumin is low, correct serum level
vancomycin
trough: 15-20 mcg/mL for most serious infections
warfarin
Goal INR is 2-3 for most indications; 2.5-3.5 with mechanical mitral valves
RBCs have an average life span of…
120 days
The CBC includes…
WBC, Hbg, Hct, Platelets
The basic metabolic panel (BMP) includes…
Na, K, Cl, HCO3, BUN, SCr, and glucose
A comprehensive metabolic panel (CMP) includes…
everything in the BMP plus albumin, ALT, AST, total bilirubin, and total protein
Leukocytosis refers to…
increased WBCs
Polycythemia refers to..
increased RBCs
Thrombocytosis refers to…
increased platelets
Leukopenia refers to…
decreased WBCs
Thrombocytopenia refers to…
decreased platelets
Myelosuppression refers to…
decreased WBCs, RBCs and platelets
Agranulocytosis refers to…
decreased granulocytes
Agranulocytosis can be due to…
clozapine, propylthiouracil, methimazole, procainamide, carbamazepine, SMX/TMP and isoniazid
Glucose-6-phosphate dehydrogenase (G6PD) is…
low in patients with G6PD deficiency
The RBC destruction with G6PD deficiency is triggered by…
stress, foods (fava beans) or these drugs: dapsone, methylene blue, nitrofurantoin, pegloticase, primaquine, rasburicase, sulfonamides
Which drugs can contribute to low sodium levels?
carbamazepine, oxcarbazepine, SSRIs, diuretics, desmopressin
TG, a 72-year-old male, is hospitalized with a PE. HE is receiving unfractionated heparin initiated at a rate of 1,000 units/hr. The control value at the hospital is 22-38 seconds. Select the correct test and appropriate treatment level for this patient.
aPTT, 44 seconds (Tx goal: 1.5x-2.5x control)
Which medications can cause Ca levels to increase?
Ca supplements, vitamin D, thiazide diuretics
Which medications can cause Ca levels to decrease?
systemic steroids, long-term heparin, loop diuretics, bisphosphonates, cinacalcet, calcitonin, foscarnet, topiramate
Which medications can cause decreased bicarbonate levels and metabolic acidosis?
topiramate, zonisamide, salicylate OD
Which medications can cause increased bicarbonate levels?
loop diuretics, systemic steroids
Drug-induced lupus erythematosus (DILE) can be caused by many drugs including:
anti-TNF agents, hydralazine, isoniazid, methimazole, methyldopa, minocycline, procainamide, propylthiouracil, quinidine, terbinafine
Calcium, total. Correct if albumin is low.
8.5-10.5 mg/dL
Calcium, ionized.
4.5-5.1 mg/dL
Chloride
95-106 mEq/L
Magnesium (Mg)
1.3-2.1 mEq/L
Phosphate (P)
2.3-4.7 mg/dL
Potassium (K)
3.5-5 mEq/L
Sodium (Na)
135-145 mEq/L
Bicarbonate (HCO3 or “bicarb”)
Venous: 24-30 mEq/L
Arterial: 22-26 mEq/L
Blood Urea Nitrogen (BUN)
7-20 mg/dL
Serum creatinine
0.6-1.3 mg/dL
Anion gap (AG)
5-12 mEq/L
Magnesium levels can increase due to…
Mg-containing antacids and laxatives with renal impairment.
Magnesium levels can decrease due to…
PPIs, diuretics, amphotericin B, foscarnet, echinocandins, diarrhea, chronic alcohol intake
Potassium levels can increase due to…
ACE inhibitors, ARBs, aldosterone receptor antagonists (ARAs), aliskiren, canagliflozin, cyclosporine, tacrolimus, mycophenolate, K supplements, SMX/TMP, drospirenone-containing oral contraceptives, chronic heparin use, NSAIDs, pentamidine
Potassium levels can decrease due to…
steroids, beta-2 agonists, conivaptan, diuretics, insulin, mycophenolate (both increase and decrease)
Blood Urea Nitrogen (BUN)
increased in renal impairment and dehydration. Used with SCr (eg. BUN:Scr ratio) to assess fluid status and renal function
anion gap= (Na+ K) – (Cl + HCO3)
Calculated, but may be reported. The presence of an increased anion gap suggests metabolic acidosis.
White Blood Cells (WBCs)
4,000-11,000 cells/mm^3
White Blood Cells (WBCs)
Used to diagnose and monitor infection/inflammation. Can increase as an acute phase reactant, indicated a systemic rxn to inflammation or stress.
White Blood Cells (WBCs) can increase due to…
systemic steroids, colony-stimulating factors, epinephrine
White Blood Cells (WBCs) can decrease due to…
clozapine, chemo that targets the bone marrow, carbamazepine, cephalosporins, immunosuppressants (eg. DMARDs, biologics), procainamide, vancomycin
Neutrophils (aka “segs”, polymorphonuclear cells)
45-73%
Bands
3-5%
Eosinophils
0-5%
Basophils
0-1%
Lymphocytes
20-40%
Monocytes
2-8%
Bands are…
immature neutrophils released from bone marrow to fight infection (called a “left shift”)
Eosinophils can go up in…
drug allergy, asthma, inflammation, and parasitic infection
Basophils can go up in…
inflammation, hypersensitivity reaction, leukemia
Lymphocytes can go up in…
viral infections, lymphoma
Lymphocytes can go down in…
bone marrow suppression, HIV or due to systemic steroids
Monocytes can go up in…
chronic infections, inflammation, stress
The direct Coombs Test is used to…
determine the cause of hemolytic anemia. It is positive in drug-induced hemolysis caused by penicillins and cephalosporins (long-term use and high doses), dapsone, isoniazid, levodopa, methyldopa, methylene blue, nitrofurantoin, pegloticase, primaquine, quinidine, quinine, rasburicase, rifampin, and sulfonamides. If positive, stop the drug.
Platelets
150,000-450,000/mm^3
Spontaneous bleeding can occur when…
platelets are <20,000/mm^3. Platelets can decrease due to heparin, LMWHs, fondaparinux, glycoprotein IIb/IIIb receptor antagonists, linezolid, valproic acid, chemo that targets bone marrow
