RAF pilots and aircrew are being instructed on the safest way to use sleeping pills to avoid fatigue.
It follows a record number of interceptions by British aviators along Nato’s eastern border, as tensions with Russia rise.
RAF Typhoon jets intercepted 50 Russian aircraft and flew more than 500 hours during four months of air policing.
Such is the tempo for crews that RAF medics have reissued warnings about the use of permitted medication on operations.
The RAF’s senior medic, Wing Commander Felicity Leaming, wrote in the MoD’s Air Clues safety magazine: “There are instances where getting good quality sleep of adequate duration is not possible.
“Issues on deployment, such as austere and noisy accommodation, changing shift patterns and time zones can all have a negative impact on our sleep.
“In these circumstances (and only in specific circumstances such as Ops and Exercises), military doctors can prescribe medications compatible with flying that can aid sleep.”
Unlike the US Air Force, which allows pilots to use a list of stimulants during the day, RAF crews are generally limited to Temazepam, to assist rest patterns, and melatonin, to counter jet lag.
She added: “Both medications require a trial period when the individual is not flying to ensure there are no side effects.”
Wing Cdr Dai Whittingham, chief of the UK Flight Safety Committee, said: “Taking sleeping pills is not new among RAF personnel.
“There are times when it is impossible to get proper sleep.”
An RAF source added: “The recent air policing mission resulted in a record number of intercepts.
“The point is not to interfere with Russian aircraft flying in international airspace. It is to show we consider it our business to know what they are doing.”