Four days of atomoxetine reduced selected subjective, blood-pressure and cortisol responses to dextroamphetamine in a small human experiment. That finding does not establish that atomoxetine treats stimulant addiction or prevents harms from uncontrolled stimulant use.
Sofuoglu and colleagues studied ten healthy volunteers in a crossover design. Participants received atomoxetine, 40 mg daily, or placebo for four days. On the fourth day of each treatment period, they received oral dextroamphetamine at 20 mg per 70 kg.
The investigators followed blood pressure, heart rate, plasma cortisol and subjective ratings. The comparison concerned atomoxetine versus placebo pretreatment; the dextroamphetamine challenge itself did not have a separate placebo condition.
Atomoxetine attenuated dextroamphetamine-associated increases in systolic and diastolic blood pressure and plasma cortisol. Ratings of stimulation, feeling high and good drug effects were also lower after atomoxetine pretreatment.
The broader Profile of Mood States measure did not show a significant treatment effect. The findings therefore concern selected responses, not suppression of every subjective or physiological consequence.
The measured plasma endpoint was cortisol, a hormone. It was not a quantified dextroamphetamine concentration, and lower cortisol cannot be translated into less drug in the body or a specific reduction in impairment.
Similarly, reduced stimulation ratings do not establish normalized judgment or safe driving. The experiment did not directly test those functions.
The sample was small, participants were healthy rather than a treatment-seeking addiction population, and only one dose of each medication was tested. Four days cannot establish chronic efficacy or safety. The lack of a placebo amphetamine challenge also complicates interpretation of expectancy-sensitive ratings.
The results support further investigation of noradrenergic contributions to amphetamine responses. They do not demonstrate reduced drug-taking, sustained abstinence or clinical benefit in stimulant use disorder, and they do not provide a basis for self-directed drug combinations.
Related reading: Why self-report and urine results can disagree.