In early February, the newspapers jubilantly announced the end of the search for a magic bullet that would successfully treat the depression and anxiety that affects an estimated one in four women and one man in eight at some point in their lives.
SmithKline Beecham launched a new drug that they claim is highly effective with none of the side effects of the old antidepressant drugs the monoamine oxidase (MAO) inhibitors and the tricyclics (also known as the antipsychotic drugs).The drug, paroxetine, marketed here as Seroxat and in the States as Aropax, is a new category of drug called a "selective serotonin uptake inhibitor", or a 5HT drug. One cause (or outcome) of depression and suicidal behaviour is believed to be low levels of a brain chemical known as serotonin, or 5HT. Paroxetine works by increasing the availability of serotonin in the brain by slowing the passage of this neurohormone into nervous system cells. According to The Pill Book by Harold M. Silverman (Bantam), this type of drug takes about four weeks to work, and stays in the body several weeks after you stop taking it.
In a press release (handed out for "the attention of accredited medical correspondents only", whatever that means) SmithKline Beecham noted several advantages of Seroxat over the older tricyclic antidepressants. These include (and we quote):
Effective therapy for patients who can return to a normal, economically active life because Seroxat is highly selective and more precise in action than other antidepressants.
Effective treatment of anxiety and sleep disturbance often associated with depression.
Enhancement of the patient's quality of life. Seroxat does not cause sedation, or impair thinking or physical activity, nor does it have a stimulant or alerting effect. Thus its neutral effects in this regard distinguish it from other available antidepressants.
Fewer side effects and excellent tolerability, compared with the older tricyclic antidepressants, which enhances compliance and enables more patients to benefit from the treatment.
Enthusiasts are already planning to widen the uses of paroxetine for migraine or overweight patients, those with cancer experiencing nausea from anticancer drugs, and people with obsessive compulsions, like handwashing. And because there is some evidence that this kind of drug reduces dependence (unlike the benzodiazepines) by stimulating the reward mechanism in the brain, doctors are discussing the possibility of using paroxetine to help control smoking and dependence on other drugs.
The Financial Times assured readers that paroxetine has far fewer side effects than the older anti depressants, comparing it with Eli Lilly's 5HT Drug, Prozac (fluoxetine). Launched three years ago and hailed in the media as the breakthrough medicine has been waiting for to treat depression, Prozac quickly became America's best selling anti depressive, with sales expected to reach more than £500 million this year.
What the FT failed to report was what has happened in the States with Prozac and also the cautionary notes Eli Lilly has sounded in the American drugs bibleThe Physician'sDeskReference. Speaking on behalf of SmithKline Beecham, Alan Chandler assures us that paroxetine is not identical in chemical makeup to Prozac but more "selective in hitting the right centres of the brain". Although one cannot assume that Seroxat's side effects will be the same as those of Prozac, Chandler admits that there is a "similar spectrum" of side effects. Consequently it's worth looking at America's experience with its first 5HT drug before automatically running to your doctor for a prescription for this new one.