Desyrel (trazodone hydrochloride) works on the serotonin system. Rather than being used for its antidepressant effects, it is most often prescribed along with Prozac because the drowsiness Desyrel induces counteracts Prozac's tendency to produce insomnia. Desyrel's other side effects include headache, upset stomach, low blood pressure, dizziness, and dry mouth. In men, it can also cause a dangerous condition called priapism-painful, drug-induced erections that may not end upon discontinuing the drug. These side effects explain why Desyrel is seldom prescribed as an antidepressant.
Effexor (venlafaxine hydrochloride) is chemically similar to an antidepressant compound in chocolate known as phenylethylamine (PEA), sometimes associated with the "love effect." It is likely that PEA raises the level of endorphins in the brain, which creates a sense of well-being. The tradition of giving chocolates on Valentine's Day reflects our intuitive knowledge of this effect.
Effexor is able to inhibit serotonin re-uptake as effectively as Prozac, yet it also boosts norepinephrine levels much as the tricyclic drugs do. That means it provides the benefits of the tricyclic medications without producing many of their side effects. Effexor also provides benefits for nearly half of the patients who do not respond to other antidepressant drugs, a far higher response rate than for other medications.
However, some 37 percent of the patients who try Effexor report problems with nausea, and one in every five persons experience dizziness, drowsiness, or dry mouth. Sleep disturbances can occur, as well. It can also increase blood pressure, so persons with high blood pressure should avoid the drug. On the good side, it does not seem to intensify the effects of tranquilizers or alcohol. It must be taken two or three times per day due to its short half-life, and dosages should be tapered off over two weeks to avoid withdrawal symptoms of severe rebound anxiety and depression. This can be extremely disabling, and sometimes even dangerous. I have seen suicidal depression result from sudden Effexor withdrawal.
The Problem of Side Effects
Scientific studies and the personal experiences of millions of patients have given us new insight into the frequent side effects produced by synthetic antidepressants. We now know that some of these medications can cause problems in up to a third of all users, forcing some to stop treatment altogether. We have also learned that particular classes of drugs are better tolerated than others. The MAOIs, for example, have fewer side effects than the tricyclics, but still produce multiple actions within the body that are unrelated to depression. These drugs can be particularly troublesome, even life-threatening, when taken in combination with certain foods or chemicals.
The reason for these side effects is related to the nature of synthetic drugs. When we affect one system in the body, we often affect others in both a positive and negative sense. For instance, a class of drugs called beta-blockers, commonly prescribed for high blood pressure, often adversely affect the brain's chemistry, causing depression. It simply isn't possible to isolate the brain biochemically from the circulatory system. Medications may have a single intended action, but it is impossible for them to not affect other parts of the body. This often creates unwanted, and sometimes dangerous, side effects (see Talking Back to Prozac by Peter Breggin (ST. Martin's). I have seen very severe toxic reactions to SSRIs-resulting in permanent damage-in susceptible individuals.