Allergy and cold
Doxylamine
First-generation antihistamine (sedating)
Other names: Unisom, NyQuil
Wait
60 hours
after the last dose
Other FAA documents add more.
If used routinely
The examiner should defer
Examiner
The examiner can issue when the document's criteria are met
FAA label
CONDITIONALLY ACCEPTABLE
The FAA's allergy sheet lists doxylamine as a conditionally acceptable sedating antihistamine — it may be used occasionally (one or two times a week) if other certification criteria are met, with the stipulation that the pilot not exercise the privileges of the airman certificate while taking it, and daily use is not acceptable — and its table lists doxylamine among the first-generation medicines, prints fewer times than names beside them, and does not say which time is whose; the sheet says an initial observation time is required to mitigate central nervous system risk, either as noted in the table or 5 times the half-life or maximal dosing interval after the last dose.
Track your medicationsCompare FAA documents: doxylamineWhat each of the three FAA documents says, in plain wordsOpen
Wait
- the FAA's over-the-counter guide gives the 60 hours, in its wait after the last dose of a No Go medication
- the allergy sheet's table does not say which of its times is doxylamine's
- the sheet's alternative is 5 times the half-life or maximal dosing interval after the last dose
The FAA's Do Not Fly list does not name doxylamine; it names first-generation sedating antihistamines as a category, prints diphenhydramine and chlorpheniramine, and points to the allergy sheet, so Crosscheck matched doxylamine to that list through its class. If the pilot uses the medications on that list routinely, it says the examiner should defer, and it says all currently available sleep aids, both prescription and OTC, can cause impairment of mental processes and reaction times, even when the individual feels fully awake.
The FAA's over-the-counter guide gives a wait time of 60 hours for doxylamine, lists it under sleep aid products as "No Go", among the products to avoid, which it says can cause incapacitation, with a "hang-over effect" morning after safety concern as its rationale, and lists Nyquil, which it says contains doxylamine, as No Go. The guide says to wait at least five dosage intervals after the last dose before flying if the pilot takes any of its No Go medications or has previously had side effects from the medication. The documents do not say the same thing; the allergy sheet is the FAA's specific guidance for these medicines and is shown first, and all three are quoted.
Show the FAA's words: doxylamineThe official FAA wording: six passages, each with its document and dateOpen
CONDITIONALLY ACCEPTABLE (Sedating) Antihistamine Medications
May be used occasionally (1-2 x per week) as a single agent or in any combination product if other certification criteria are met. NOT FOR DAILY USE.
Medication Drug Class Initial observation
Oral: All First-Generation Histamine-H1 receptor antagonist
diphenhydramine (Benadryl)**
doxylamine (Unisom)
brompheniramine
chlorpheniramine (Coricidin; ChlorTrimeton)
clemastine (No brand)
60 hours
60 hours
5 days
5 days
Conditionally acceptable medications:
May be used occasionally (1-2 times a week) with the stipulation that the airman not exercise the privileges of airman certificate while taking the medication.
Daily use is NOT acceptable.
Initial observation time: Required to mitigate central nervous system risk, either as noted in the table below or 5x the half-life or maximal dosing interval after the last dose.
DO NOT FLY (DNF) MEDICATIONS
The following medications have aeromedically concerning safety profiles. All medications listed below may cause sedation or drowsiness, impairing cognitive function and seriously degrading pilot performance.
ALLERGY MEDICATIONS (1st GENERATION)
Sedating Antihistamines:
Found in many over-the-counter (OTC) allergy and other types of medications, as a single agent or in any combination product.
Applies to nasal, ophthalmic, AND oral formulations.
diphenhydramine (Benadryl)
chlorpheniramine (Coricidin; ChlorTrimeton)
See pharmaceutical, Allergy – Antihistamine & Immunotherapy Medication
DO NOT FLY (DNF) MEDICATIONS
AMEs should caution pilots on use and provide additional No Fly wait times where applicable. If applicant is using the following medications routinely, AMEs should DEFER.
DO NOT FLY (DNF) MEDICATIONS
The following medications have aeromedically concerning safety profiles. All medications listed below may cause sedation or drowsiness, impairing cognitive function and seriously degrading pilot performance.
SEDATIVES/SLEEP AIDS
All currently available sleep aids, both prescription and OTC, can cause impairment of mental processes and reaction times, even when the individual feels fully awake.
4. NO GO Medications:
If you take any of the NO GO medications listed in the OTC Medications Reference Table OR if you have previously had side effects from the medication, wait at least five (5) dosage intervals after the last dose before flying.
Caution: Sedating antihistamine medications have a long half-life so wait time is 60 hours for both diphenhydramine (Benadryl) and doxylamine (Unisom), 5 days for both chlorpheniramine and clemastine.
AVOID
These can cause incapacitation.
NO GO
Sleep aid products
Doxylamine (e.g., Unisom)
“Hang-over effect” morning after safety concern.
Nyquil (contains doxylamine)