The theophylline analog that may be monitored in the treatment of neonatal apnea is
D) caffeine
A patient who overdosed on digoxin was given Digibind. The physician ordered a stat digoxin level 1 hour later. Which of the following is the most appropriate response?
D) inform the physician that a digoxin concentration cannot be accurately determined.
The blood concentration of the drug reflects its concentration at its target receptor:
1. Immediately after ingestion/infusion
2. At least two hours after ingestion/infusion
3. After distribution is complete.
4. Just before the next dose
A) 1 and 4
The site in the body where most drug metabolism occurs is the
A) liver
The best time to collect a sample for therapeutic monitoring of most oral drugs is
C) immediately before the next dose.
For which of the following metals should all children be tested by age 6?
B) lead
As a rule of thumb, the steady state concentration of a drug is achieved after how many half lives?
B) 4-5
The specimen of choice for monitoring levels of the immunosuppressant drugs cyclosporine, tacrolimus andsirolimus is
C) whole blood
A drug known to increase the metabolism of many other drugs is
D) phenobarbital
The fraction of a dose that reaches the bloodstream is known as a drug's
A) bioavailability.
The halflifeof a drug is 4 hours. If the initial concentration is 100 mcg/mL, in three halflivesthe expected drug concentration would be
B) 13 ug/mL
When testing for therapeutic drugs, steady state refers to
D) the time when net drug administered is equal to net drug eliminated
The legal limit for ethanol (ETOH) while driving in California is
B) 0.08% in whole blood.
The metabolite THCCOOHcan be detected by immunoassay for several days after the use of
C) marijuana.
The most sensitive and specific method for identifying drugs of abuse is
A) GC mass spectrometry (GCMS).
When receiving a assay request for the drug on the left, which drug on the right should also be measured?
+Gentamicin
+Primidone
+Procainamide
-Digoxin
-Phenytoin
-Phenobarbital
-Tobramycin
-No other drug need be measured
-Amikacin
-NAPA
Getamicin: No other drug need be measured
Primidone: Phenobarbital
Procainamide: NAPA
What is occurring in phase I metabolism of a therapeutic drug?
D) Chemical modification such as hydrolysis or oxidation
The group of enzymes that are particularly involved in phase I metabolism of drugs is
B) cytochrome P450.
All of the following are antiepileptic (anticonvulsant) drugs EXCEPT
A) procainamide.
The drug most suited for measurement of the free fraction in appropriate circumstances is
A) phenytoin.
The most common method of measuring ethanol in clinical laboratories is
A) enzymatic assay using ADH.
A 56 y.o. female patient has a digoxin measured stat just prior to his 11:00 am doctor's appointment. The result is 6.2 ng/mL (ther. range 0.82.0)and when you call this critical value, the physician responds that the patient is only taking a very low dose every morning and the EKG he just took shows no signs of digoxin toxicity. What is the most likely cause of this discrepancy?
C) incomplete distribution
A mass spectrum is a plot of
A) m/z vs abundance
A homeless man is taken to the ED with profound "inebriation", hyperventilation and a fruity odor on his breath. Stat glucose is 176 mg/dL and BHB (beta hydroxybutyrate)is normal. Urinalysis is normal except for trace glucose and 1+ ketones. Osmolal gap is elevated. Which test would you recommend to a physician?
A) Serum volatiles
Ethylene glycol ingestion might be accompanied by all of the following EXCEPT
C) elevated acetone.
The following drugs all have somewhat specific "antidotes" that can minimize toxicity EXCEPT
C) ethanol.
You are called to court to testify about a sample drawn in the ED from a driver involved in a collision. The serum alcohol was 86 mg/dL. The prosecution says this proves the driver was legally drunk. The defense counters with one of the following arguments. Which is the most defensible from a laboratory point of view?
A) The sample tested was serum, so the results do not correspond to legal definitions of DUI.
Doubling the dose of a drug that follows "saturation" kinetics might lead to
A) a quadrupling of steady state drug levels.
A concurrently administered drug that might affect drug levels of gentamicin is
A) carbenicillin.
A potential interferent in digoxin immunoassays in pregnant women and newborns is
B) DLIS
The drug whose dosing would most likely need adjustment in a patient with renal disease is
-is hemoglobin with Fe3+.
-is hemoglobin complexed with carbon dioxide.
-is hemoglobin complexed with carbon monoxide.
-are unstable and should be iced or analyzed w/in 30 minutes.
-are unstable and should be iced
-must be collected anaerobically.
-are stable and can be analyzed rou栱nely.
Methemoglobin: is hemoglobin with Fe3+.
Methemoglobin samples: are unstable and should be iced or analyzed w/in 30 minutes.
Carboxyhemoglobin: is hemoglobin complexed with carbon monoxide.
Carboxyhemoglobin samples: are stable and can be analyzed routinely.
are stable and can be analyzed routinely.
D) CO binds to the O2 binding site, preventing O2 binding.
Proper interpretation of serum acetaminophen levels and hepatic necrosis risk require that the sample be drawn
A) no sooner than four hours after ingestion
Definition of a therapeutic range by a laboratory
C) uses data from clinical trials
Match the following:
+what the body does to a drug
+what a drug does to the body
The type of drug administration that shows the MOST variability among patients is:
C) oral
The drug mentioned in class as a potential candidate for dosing decisions made on pharmacogenetics is
B) warfarin
The drug for which peak levels would be most useful is
B) vancomycin
Monitoring of which of the following psychotropic drugs (or drug classes) is most appropriate and common.
E) lithium
Iron was recommended to be available stat, ideally with TIBC. Which of the following results would be the most concerning in a presumed iron ingestion (all units are mcg/dL)?
A) Fe 300, TIBC 250
Determination of carboxyhemoglobin in the clinical laboratory would be most commonly performed in which lab section?
A) blood gases
For the following ingestions, what compound would provide the most concerning toxicity?
