Effects of Modafinil and Caffeine on vigilance in low, medium and high caffeine consumers during the circadian trough in healthy RNLAF aircrew: a randomized controlled trial

Recruitment & Eligibility

Status: Completed

Sex: Not specified

Target Recruitment: 36

Inclusion Criteria

In order to be eligible to participate in this study, a subject must meet all of the following criteria:
I. The potential participant has given informed and written consent and is able to comply with all study assessments scheduled in the protocol.
II. All personnel need to be aircrew members of the Royal Netherlands Air Force, irrespective of their position.
III. All subjects need to be between 18 and 60 years of age.
IV. All subjects need to be in good health, and may not have any chronic diseases.

Exclusion Criteria

A potential subject who meets any of the following criteria will be excluded from participation in this study:;Exclusion criteria are mostly based on possible side effects or interactions of one or both of the medicines.
i. Pregnant or nursing women are not eligible, modafinil is possibly teratogenic. There has not been enough research to prove modafinil safe for use during pregnancy. A pregnancy test will be performed on every test day (in the morning).;ii. People with known heart, kidney or liver disease or neurological complaints are not eligible;People who use medication that is being metabolized through CYP3A4/5, CYP2C19 of CYP2C9, since this might alter the plasma levels of the used medication and modafinil. It does not change the levels of Modafinil.
iii.
iv. A history of psychiatric illness disqualifies for the trials; this includes sleeping disorders;v. One week prior to starting every trial day, all subjects need to be (and remain) in a time zone that is a maximum of 4 time zones away from the CET time zone in which the research center lies. (GMT+1, daylight savings GMT+2). This to exclude jet lags that might confound the test results.;vi. Known allergies for caffeine, modafinil or any of its ingredients or metabolites. ;Women using hormone based birth control ( e.g. oral contraceptives, intra-uterine device) will be very well informed prior to taking part due to the interference between hormones and modafinil. There will be no interference with the working mechanism of modafinil or its efficacy, but there is a known decreased effect of the contraceptive when used simultaneously with modafinil. Women using hormone-based contraceptives can therefore participate if they are willing to use other non-hormone based contraceptives as well. It is therefore not a direct exclusion criterion, but women will be informed concerning the lower efficacy of hormonal contraceptives.

Study & Design

Study Type: Interventional

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
<p>Objective and subjective measurements with regard to vigilance. The following<br /><br>primary parameters will be measured:<br /><br>Vigilance & Tracking Test (VigTrack)<br /><br>- Root mean square of tracking error<br /><br>- Percentage omissions<br /><br>- Reaction time<br /><br>Psychomotor Vigilance Task (PVT):<br /><br>- Reaction time<br /><br>- Lapses<br /><br>- Misses</p><br>

Secondary Outcome Measures

Name	Time	Method
<p>Secondary parameters include:<br /><br>Besides these objective measures, subjective measurements with regard to<br /><br>measuring sleepiness will be performed including the Stanford Sleepiness scale<br /><br>(SSS) and the Epworth Sleepiness scale (ESS). Two consecutive days before the<br /><br>test day, they will have to keep a journal concerning their fatigue level,<br /><br>their sleeping hygiene and habits, and daily caffeine intake.<br /><br>Bloodsamples (intravenous) will be conducted to determine exact objective<br /><br>caffeine- and modafinil levels.</p><br>

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