Alcohol Metabolism & Physiology Flashcards

In a retrograde extrapolation calculation, a technician uses an elimination rate to estimate a subject's BAC at an earlier time. The most commonly cited average elimination rate for forensic purposes is approximately:

Answer: 0.015 g/dL per hour

The average alcohol elimination rate is approximately 0.015 g/dL per hour, though individual rates typically range from 0.010 to 0.025 g/dL per hour.

A subject who has developed significant alcohol tolerance will demonstrate which metabolic change compared to a naïve drinker?

Answer: Induced CYP2E1 activity leading to faster elimination

Chronic alcohol use induces CYP2E1 (MEOS), which increases the liver's capacity to metabolize alcohol and results in faster clearance rates in tolerant individuals.

Food in the stomach affects alcohol absorption primarily by:

Answer: Slowing gastric emptying and delaying alcohol passage into the small intestine

Food delays gastric emptying, which keeps alcohol in the stomach longer and slows its passage to the small intestine where the majority of absorption occurs.

Which of the following best describes 'first-pass metabolism' of alcohol?

Answer: Partial metabolism of alcohol by gastric and hepatic enzymes before it reaches systemic circulation

First-pass metabolism refers to the pre-systemic oxidation of alcohol by gastric ADH and hepatic enzymes as alcohol passes through the stomach and liver before entering general circulation.

A breath alcohol instrument uses an infrared sensor. Compounds such as acetone (present in diabetic ketoacidosis) may cause a false-positive result because:

Answer: Acetone absorbs infrared light at wavelengths similar to ethanol

Acetone and some other volatile compounds absorb infrared energy at wavelengths overlapping with ethanol's absorption bands, potentially producing a false-positive on IR-based instruments.

Approximately what percentage of consumed alcohol is eliminated through routes other than hepatic metabolism (e.g., breath, urine, sweat)?

Answer: Less than 10%

Only about 2-10% of ingested alcohol is excreted unchanged via breath, urine, and sweat; the remaining 90-98% is metabolized hepatically.

The pyloric valve's role in alcohol pharmacokinetics is significant because:

Answer: It controls the rate at which stomach contents, including alcohol, empty into the small intestine

The pylorus regulates gastric emptying rate, which is a major determinant of how quickly alcohol reaches the absorptive surface of the small intestine.