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Ground Trial for Medication

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Definition

This Clinical Practice Guideline applies to holders of Class 1, 2, or 3 medical certificates who commence medication, or whose medication undergoes a significant change in dose. The principles apply to a wide range of medical conditions, including those listed in the Clinical Practice Guidelines, where specific treatments and medications may be referenced.

Aeromedical Implications 

Use of medication by certificate holders is common, and many medications can be taken without concern.  However, all medications have the potential to cause idiosyncratic reactions, in addition to the known side-effect profile of certain classes of medication. 
The underlying condition which requires medication treatment is safety relevant, therefore, it is important that certificate holders who take medication complete a ‘ground trial’ prior to resuming flying or controlling.   At the end of the ground trial, the certificate holder’s DAME should establish:

• Satisfactory control of the underlying medical condition for which the medication is required.
• Absence of significant side-effects of the medication.

Different medications require a ‘ground trial’ of different durations; CPG on medication refers.
It is important to note that a medication ground trial does not mitigate all aviation risks, due to delayed or paradoxical reactions. For example, Isotretinoin can cause decreased night vision, loss of colour sensitivity and psychological side effects which are not immediately apparent.
Given changes in pharmacokinetics and sensitivity to side-effects with advancing age, it is recommended that ground trials be repeated after age 45 for medications that are taken infrequently.

Effect of aviation on treatment

• Reduced ambient pressure leading to gas expansion, especially where medication produces increase in intestinal gas or reduction in intestinal motility.
• Increase in +Gz forces, especially in aerobatics, can provoke hypotension and lead to syncope.

Effect of treatment on aviation

Common aeromedically-significant side effects include, but not limited to:

• Fatigue and daytime sleepiness (for sleeping tablets, this must be assessed at 12 hours after taking the medication).
• Neurocognitive impairment, including memory and speed of processing
• Depression or mood lability
• Decrease in visual acuity or blurred vision
• Nausea,
• Musculoskeletal aches and pains
• Postural hypotension
• Vertigo
• Elevation of LFTs or renal function.

Approach to medical certification

Based on the condition

• The underlying condition must be satisfactorily controlled.

Based on Treatment

• Absence of aeromedically significant symptoms, as listed above:

Demonstrated Stability

(commensurate with half-life of medication)
Acceptable biochemical parameters, if necessary
Affirmative self-assessment of:

• Alertness
• Orientation
• Cognitive performance

Written confirmation by the DAME is satisfactory confirmation of a satisfactory ground trial.

Risk assessment protocol - Information required

New cases

• A report from your DAME confirming absence of symptoms or side-effects will be satisfactory evidence of completion of a ground trial.

Indicative outcomes

Favourable

• Underlying condition satisfactorily controlled by a permissible medication,No aeromedically significant side effects, including drowsiness, fatigue, or cognitive impairment.

Unfavourable

• Poorly controlled medical condition.
• Presence of one or more aeromedically-significant symptoms.
• Cognitive impairment, including processing speed.

Information for the Certificate Holder

Flying and controlling are physically and physiologically demanding tasks, and any side effects associated with the use of medication can have significant safety implications in the aviation environment.  A certificate holder should ground themselves whenever they commence a new medication, or undergo a significant change in dose of an existing medication.

The period of ground trial varies for different medications.

The certificate holder should seek clearance from their DAME prior to resuming flying or controlling.

Given changes in pharmacokinetics and sensitivity to side-effects with advancing age, it is recommended that ground trials be repeated after age 45 for medications that are taken infrequently.

Disclaimer

The Clinical Practice Guideline is provided by way of guidance only and subject to the Clinical practice guidelines disclaimer