Access and Utilization of New Antidepressant and Antipsychotic Medications. Chapter VII. Pharmacoeconomics of Newer Antidepressant and Antipsychotic Medications

01/01/2000

As health care in the United States has become increasingly cost-conscious, providers are increasingly encouraged not only to consider the outcomes of treatment alternatives, but also to consider and justify costs. Similarly, payers have begun to examine the interaction of cost and effectiveness more carefully. The cost-effectiveness of newer antidepressants44-49 and antipsychotics50-52 has been the subject of several recent reviews. In addition, numerous reviews of individual agents exist.53-58 The following review of the cost-effectiveness literature is designed to provide a high-level overview of the subject and the principal conclusions. The reader is referred to the reviews cited above for more detailed information.

In brief, the following limited review of the literature found:

Antidepressants

The literature provides no consistent differences in total treatment costs associated with the use of different antidepressant agents, although individual studies have claimed that one particular agent is superior to another.

  • The vast majority of studies are sponsored by pharmaceutical manufacturers.
  • Most of these studies have found that treatment with the pharmaceutical manufactured by the sponsor is no more costly than treatment with comparative agents.
  • It is unlikely that manufacturers would allow publication of a study that found a negative result for their agent.
  • However, results from studies sponsored by manufacturers do not differ substantially from those obtained from studies sponsored by independent or government sources.

Several case studies have found that treatment with newer agents is cost-saving compared to treatment with older agents, although a few other studies have found the converse to be true. If differences do exist, it might be said that modest evidence exists for SSRIs being more cost-effective than TCAs.

  • Antidepressant treatment with fluoxetine may yield lower costs than treatment with TCAs -- particularly for post-initiation therapy. Stronger evidence exists, however, for greater compliance with fluoxetine than with TCAs.
  • Studies on the costs of paroxetine relative to imipramine are inconclusive; however the evidence is strong for greater compliance or treatment continuation for paroxetine.
  • Treatment with sertraline may result in lower total costs than treatment with TCAs. One study also asserts that sertraline is more effective than TCAs. Taken together, it is reasonable to conclude that treatment with sertraline is more cost-effective than treatment with TCAs.
  • The evidence on venlafaxine tends to suggest that treatment with venlafaxine is more cost-effective than treatment with either TCAs or trazadone.
  • Although two studies differ on the relative costs of treatment with nefazodone, both studies do suggest that treatment with nefazodone is more cost-effective than treatment with imipramine.

The pharmacoeconomic evidence on the SSRI studies makes it reasonable to conclude that no clear distinctions exist between these SSRIs--fluoxetine, sertraline and paroxetine--with respect to either costs or cost-effectiveness of treatment. Data claiming cost superiority for venlafaxine over SSRIs is of insufficient quantity to be convincing.

In numerous cases researchers have failed to find a difference between treatment groups.

Patient compliance with the newer antidepressants is considerably better than with the old. To that effect, the newer antidepressants may be more cost-effective than the older antidepressants, particularly over longer courses of therapy.

These studies do not support the preferred use of older agents (i.e., TCAs) as a valid method of cost-containment, if total health-systems cost are to be included.

Antipsychotics

Evidence from the pharmacoeconomic literature shows that treatment using the new antipsychotics exhibits economic advantages over treatment using the older antipsychotics. This evidence for olanzapine and clozapine is superior to the corresponding evidence for risperidone.

  • The limited models comparing risperidone and clozapine to the older antipsychotics suggest that, despite their higher medication costs, risperidone and clozapine may be more cost-effective than older antipsychotics (e.g., haloperidol) in the treatment of schizophrenia.
  • The pharmacoeconomic evidence on risperidone versus typical antipsychotics presents no clear advantage for risperidone in terms of efficacy; although on balance, risperidone may have a slight edge in cost-effectiveness.
  • Olanzapine appears to be more cost-effective than haloperidol in the treatment of schizophrenia.
  • The manufacturers of quetiapine have carefully designed a naturalistic comparative pharmacoeconomic trial in order to compare quetiapine to usual care. No results are yet available from this trial.
  • The results of numerous studies together provide strong evidence of clozapine's superior cost-effectiveness relative to older, typical antipsychotics in treatment-resistant schizophrenia.

The paucity of well-designed studies precludes drawing any conclusions regarding relative pharmacoeconomic differences among atypical antipsychotics.

  • Current inconsistencies regarding the dosages in the 2nd generation atypical antipsychotics head-to-head (risperidone vs. olanzapine) studies render the evidence inconclusive as to which agent is more cost-effective.