Bupropion has clinical efficacy similar to the SSRIs; unlike these, it has better tolerability, due to the lower incidence of adverse effects like nausea, diarrhea, somnolence, sweating, and particularly, sexual dysfunctions. The latter mainly affects male patients and largely consist in premature ejaculation. The primary objective was to evaluate sexual functioning during and after treatment with bupropion or paroxetine. Since the anti-anxiety efficacy of bupropion is controversial, the secondary objective of this study was to assess the effects of bupropion on anxiety symptoms.
Thirty patients (23 females; 7 males), who met criteria for DSM-IV-TR Major Depressive Disorder (MDD), were recruited among patients followed at the outpatient psychiatric facility at Policlinico Universitario, Catania, Sicily, Italy, to compare the efficacy and tolerability of bupropion (n = 15) and paroxetine (n = 15). Both groups were evaluated using the 21-items Hamilton for Depression Rating Scale (HAMD21), the Montgomery-?sberg Depression Rating Scale (MADRS), the Hamilton Anxiety Rating Scale (HAMA) and the Arizona Sexual Experience Scale (ASEX) at vaseline and tested again after 2 (T1), 6 (T2), 14 (T3) and 24 (T4) weeks of treatment.
Of 30 subjects enrolled, 28 completed the 24-week trial with bupropion-XL or paroxetine, with two drop-outs that occurred in the bupropion treatment group. No significant differences were found between the two groups on the HAM-D-21. From baseline to endpoint, mean HAM-D score decreased by 56.6% in group 1 (bupropion) and by 58% in group 2 (paroxetine). Similar results were obtained on the MADRS (-46.8% and -50%, respectively). On the HAM-A, scores decreased more in group 2 (-61,3%) than group 1 (-54,3%), although not significantly so (Table II). Last, the score on the ASEX decreased in group 1 from 20.9 at baseline to 14.8 (29.4%), whereas in group 2 it increased by 8.9%, from 19.5 at baseline to 21.3; the difference between the two groups was statistically significant (p < 0.01). Furthermore, score increases in group 2 were higher in males than in females (Fig. 1).
In this small, randomized controlled trial, bupropion showed comparable efficacy to paroxetine in the resolution of depressive and anxiety symptoms; there were no significant differences in latency to clinical response. Nevertheless, paroxetine, like other SSRIs, is related to sexual dysfunction as a side effect, particularly in males, whereas bupropion appears to lack this effect. This finding corresponded to our expectations; the limited sample available does not allow to clarify some fundamental aspects of the clinical effect of bupropion. These relate in particular to the actual efficacy of the drug against anxiety, and its supposed ability to reverse sexual dysfunction, iatrogenic or not. Further studies on larger samples are required to consolidate our results.