When a person is prescribed medication by their doctor, it is usually because they have a health or medical condition.
Medication to deal with that health issue, administered at the correct dosage should stabilise the condition. In most cases this means the health condition is not an issue for a polygraph examination and will not adversely affect the results. However, if the dosage of a medication has been recently increased this suggests that the original dosage was no longer effective. Therefore enough time should be allowed for the new dosage to become effective before undergoing a test.
It is important to be honest with the examiner about any health conditions otherwise this could adversely affect the results of the test.
Prior to accepting an appointment, the examiner will ask a number of questions in order to assess the person’s suitability to take a polygraph test. Any condition which affects a person physiologically is likely to impact the test. Consequently, not being honest with the examiner or deliberately with-holding information about their physical or mental health may result in the examinee wasting their money.
There are a number of myths around the polygraph and drugs. 
We have come across situations where people believe they should stop taking medication in order to take a polygraph test. Not only is this a dangerous myth but this is likely to make the person unsuitable to take a test. All medication should be taken as normal and under no circumstances should a person stop taking medication without first obtaining their doctors approval.
A further myth that taking relaxants will help a guilty person pass a test is simply not true. Under no circumstances should anyone take another person’s prescribed medication.
Once a polygraph examination is booked the examinee should not use illegal drugs prior to their appointment.
If a person “self-medicates” using illegal drugs they should be honest about this and discuss it the examiner so the examiner can establish if the person is suitable to take a polygraph examination.