Pristiq® (desvenlafaxine) is a medication developed by the company Wyeth® that has been approved for use in the United States since 2008, and in Canada since 2009. It was developed as an antidepressant and belongs to the group of antidepressants known as serotonin norepinephrine reuptake inhibitors (SNRIs). As group, SNRIs help to control the way the body synthesizes the neurotransmitters serotonin and norepinephrine, leaving more of these neurotransmitters available, which may have an elevating effect on mood. Those familiar with these medications may note that desvenlafaxine sounds very much like venlafaxine (Effexor®) and this is no mistake, as the two are closely related.
Though principally marketed for the treatment of depression, desvenlafaxine may have some off label uses and these may increase over time. In particular, the medication has been suggested as a potentially beneficial treatment for women undergoing severe symptoms of menopause. The benefit of using an SNRI is touted because it is not a hormone treatment, which may elevate risk for certain forms of cancer.
As with any medication, this antidepressant has a share of benefits and side effects. The clear benefits may be that in some people, but not all, it can help alleviate the symptoms of major depression. Like all antidepressants, desvenlafaxine runs the risk of creating dangerous suicidality in patients, especially in children, teens and young adults. Careful monitoring is required when this medication is first prescribed, and any increases in thoughts of suicide or depression should be reported to the prescribing physician.
Other side effects of desvenlafaxine can be very serious. If a person coughs up blood, develops high fever, sweating or rapid heartbeat, has memory problems, confusion or headaches, or experiences seizure, these should mean getting immediate medical help. Sometimes allergic reaction can occur which might include difficulty breathing, swelling of lips or tongue and rash, and is also an emergency. Alternately, some people given this medication may develop severe mood changes that can include manic episodes, swings between mania and depression, anxiety, or inner restlessness (akathisia). These might most occur if the medication is prescribed for those people with undiagnosed bipolar disorder.
Less severe side effects may be transient and don’t affect everyone. These can include reduction in sexual desire, impotency, inability to achieve orgasm, tiredness, dizziness, headache, stomach upset (particularly nausea), and dry mouth. Some people may also experience poor appetite. One thing known about desvenlafaxine is that it shouldn’t be taken with alcohol because this can increase incidence and severity of side effects. Many of these side effects aren’t felt or go away over time, but they should be reported to a prescribing physician.
There are many medications that may conflict with desvenlafaxine. These include most monoamine oxidase inhibitors (MAOI) antidepressants. Other medications that may have an effect on Pristiq® include lithium, St. Johns Wort, warfarin (Coumadin®) and other antidepressants. Before receiving this medication, patients should fully disclose all prescribed or over the counter medications they take so these can be considered. Moreover, it’s been determined that pregnant women and breastfeeding women should not take this medication. In the former, it can cause birth defects, and in the latter, the medication passes through breast milk.
Given the relationship to venlafaxine, those taking Pristiq®: may have some curiosity about the potential to experience withdrawal syndrome. If they stop taking desvenlafaxine, it does appear that some people will experience symptoms similar to Effexor® discontinuation syndrome. These include profuse sweating, extreme stomach upset, insomnia and inability to eat. This would suggest that safe discontinuation of the medication might be done by tapering unless it is medically necessary to discontinue more quickly.
It’s important to remember that all drugs can have an impressive list of potential side effects. This does not make them bad drugs; it just means that they’re not optimal medications for everyone. Treatment of depression is a highly individual thing, and each patient should discuss with his or her doctor the risks versus benefits of any treatment. Side effect lists for desvenlafaxine shouldn’t necessarily discourage use of the medication, but instead may help patients make informed decisions about what medications they try.
