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Wait after the first dose of a new medication

Remote Pilot (Part 107) practice question 19 of 20 on Operations / Physiology. ACS element UA.V.E.K3 · difficulty: recall. Want to answer it in a timed quiz? Use the Remote Pilot (Part 107) practice mode.

Question bank updated 2026-09-22

QUESTIONAfter taking the first dose of any new medication, over-the-counter or prescribed, how long should a pilot wait before flying in order to detect adverse side effects?

  1. AAt least 8 hours, as with alcohol
  2. BAt least 48 hours
  3. C24 hours, or 12 for OTC drugs
Show the answer and explanation

Correct answer: B. At least 48 hours

  • A — incorrect Eight hours is the alcohol rule: a crewmember may not have consumed an alcoholic beverage within the preceding 8 hours. It is not the waiting period after a first dose of medication.
  • B — correct The study guide's medication guidance states that for any new medication, over-the-counter or prescribed, a pilot should wait at least 48 hours after the first dose before flying to confirm there are no adverse side effects.
  • C — incorrect No shorter period is given, and the guidance draws no distinction between over-the-counter and prescribed drugs; the same waiting period applies to both.

BACKGROUND

Title 14 of the Code of Federal Regulations part 107 does not permit a small unmanned aircraft (UA) operation if the remote pilot in command (PIC), the person manipulating the controls, or the visual observer cannot safely carry out his or her responsibilities, and §§ 91.17 and 91.19 prohibit using any drug that affects a person's faculties contrary to safety. Virtually all medications have the potential for adverse side effects in some people, and herbal or dietary supplements and energy boosters can act the same way. Two of the most commonly used over-the-counter (OTC) drug groups, antihistamines and decongestants, can cause drowsiness and cognitive deficits, and medications containing diphenhydramine have a prolonged half-life that lengthens the time side effects are present. Because a person cannot know in advance how a new drug will affect him or her, the guidance is to allow a full observation period after the first dose before flying. The self-assessment mnemonic IMSAFE, standing for Illness, Medication, Stress, Alcohol, Fatigue, and Emotion, puts medication on the preflight checklist for every flight.

STUDY TIP

Memorize the three separate time figures in this chapter so they do not blur together: 48 hours after a first dose of new medication, 8 hours after alcohol, and 8 hours of sound sleep to cure acute fatigue. Whenever a question gives a time period, ask yourself which of the three it belongs to before answering.

KEY POINTS

  • Wait at least 48 hours after the first dose of any new medication, over-the-counter or prescribed, before flying.
  • The rule is the same for OTC and prescribed drugs, because any medication can produce side effects in some people.
  • Antihistamines and decongestants are common culprits, and diphenhydramine's long half-life keeps side effects present longer.

SOURCES

  • remote_pilot_study_guide.txt ch9 "Drugs" (IMSAFE medication component)
  • remote_pilot_study_guide.txt ch9 "Physiological Factors (Including Drugs and Alcohol) Affecting Pilot Performance" (introduction)
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SkyDrill is not affiliated with the FAA. This is an original practice item based on 14 CFR part 107, 14 CFR part 89, and the FAA Remote Pilot – Small UAS Study Guide (FAA-G-8082-22). Regulations and handbooks are revised; confirm details against the current edition.