JACKSONVILLE, FLORIDA. Dr. Elliott Richelson, MD of the Mayo Clinic has published an excellent review of the pharmacology of antidepressants. The review should be essential reading for anyone prescribing antidepressants and will help patients to participate in the decision as to which one will suit them best.
It is absolutely clear from Dr. Richelson's paper that antidepressants, even within a particular group such as the SSRIs (selective serotonin reuptake inhibitors), vary widely in their effects. Some like fluoxetine (Prozac) take weeks to become effective and weeks to eliminate from the body. Others like nefazodone (Serzone) may show their effect in a single day. Dosage recommendations also vary; Serzone must be taken twice a day, paroxetine (Paxil) once a day, and Prozac could presumably be taken just once a week.
Adverse effects, interactions with other drugs, and the detailed mechanisms by
which antidepressants act are covered in detail. Dr. Richleson also goes into
considerable detail regarding the secondary effects of antidepressants on the
adrenergic (norepinephrine) and vagal (acetylcholine) neurotransmitters and
their receptors. For example, reboxetine is the most effective inhibitor of
norepinephrine transport, paroxetine is the most potent inhibitor of serotonin
transport, and citalopram (Celexa) is the most selective antidepressant for
blocking uptake of serotonin over norepinephrine.