Can patients on aldomet have a false positive urine drug screen for amphetamines?

Question

Can patients on aldomet have a false positive urine drug screen for amphetamines?

Answer 1

Although there are many different screening assays used for amphetamines, and some are of more questionable sensitivity than others (the point of care assays using pregnancy test type strips are frighteningly so), any reliable laboratory will probably show a negative initial screen and certainly will show a negative confirmation.

Answer 2

Test kits are not very specific, they only should be used to see if further tests are indicated.  Aldomet has many features similiar in structure to amphetamine, it is easy to see how a chemical test could make a false positive.

Aldomet does not change to amphetamine in the body.

However amphetamine can change into something very much like aldomet, maybe even aldomet in the body (para hydroxylation of Amphetamine is mentioned in Goodman and Gilman's Pharmacological Basis of Therapeutics, 6th edition, page 159, but not in a newer edition). It would only take a meta hydroxylation after that to make aldomet.

The reverse reactions would be highly unlikely.

Only drug tests that use some form of chromotography (that attempts to separate the various chemicals) followed by Mass Spectra (that tells the molecular weight of the molecule) and IR spectra (the fingerprint of the molecule) have a low false postive rate.

There are many other drugs to treat high blood pressure than aldomet, consider asking your doctor to switch you to something else.

Answer 3

According to the literature in the test kits... some kits do test positive for amphetamines with aldomet.