Drug defaulting estimated by the use of a drug marker

Abstract

The incidence of failure to take prescribed drugs was investigated in 272 psychiatric patients on amitriptyline, chlorprothixene, flupenthixol, or placebo. In the trial quinine was added to the tablets as tracer. The urinary excretion of quinine was checked by thin layer chromatography. A negative quinine reaction meant that the medication was not being observed.

One hundred and eight (40%) patients had a negative quinine reaction, in the majority of cases only on one occasion. A negative reaction was demonstrated in 14% of in-patients and in 45% of out-patients. There was no correlation between a negative quinine reaction on the one hand and diagnosis, drug, duration of treatment, incidence of side-effects, sex, or age on the other. However, the quinine excretion seemed to be related to the therapeutic results. Among patients with endogenous depression on amitriptyline therapy and in patients with reactive depression on placebo there were significantly more positive quinine reactions in those who did not improve than in those who did. Patients treated with sedating drugs showed, however, a significant relationship between a positive quinine reaction and an improvement in their condition. This finding as well as the role of medication failure and the possibilities of eliminating this factor are discussed.

Key words: :

• Drug therapy
• drug defaulting
• drug marker
• psychopharmacology