desvenlafaxine

Desvenlafaxine is an oral drug that is used for treating depression. It is in a class of antidepressant drugs called selective serotonin and norepinephrine reuptake inhibitors (SNRI); a class that also contains venlafaxine (Effexor) and duloxetine (Cymbalta). (Desvenlafaxine is an active metabolite of venlafaxine, that is, it is a product of venlafaxine that is manufactured by the body from venlafaxine.) Desvenlafaxine affects neurotransmitters, the chemicals that nerves within the brain make and release in order to communicate with each other. Neurotransmitters either travel across the space between nerves and attach to receptors on the surface of nearby nerves or they attach to receptors on the surface of the nerves that produced them, to be taken up by the nerve and released again (a process referred to as re-uptake).

Many experts believe that an imbalance among neurotransmitters is the cause of depression. Serotonin and norepinephrine are two neurotransmitters released by nerves in the brain. Desvenlafaxine works by preventing the reuptake of serotonin and epinephrine by nerves after they have been released. Since uptake is an important mechanism for removing released neurotransmitters and terminating their actions on adjacent nerves, the reduced uptake caused by desvenlafaxine increases the effect of serotonin and norepinephrine in the brain. The FDA approved desvenlafaxine in February 2008.

What brand names are available for desvenlafaxine (Pristiq)?

Pristiq, Khedezla

Is desvenlafaxine (Pristiq) available as a generic drug?

GENERIC AVAILABLE: Yes

Do I need a prescription for desvenlafaxine (Pristiq)?

Yes

Desvenlafaxine can cause nausea, headaches, anxiety, insomnia, drowsiness, constipation, weakness, dry mouth, sweating, diarrhea,  and loss of appetite. Increased blood pressure can occur and should be monitored. Seizures have been reported. Sexual dysfunction (decreased sex drive and delayed orgasm and ejaculation) has been associated with desvenlafaxine. Desvenlafaxine and other SNRIs may increase the risk of gastrointestinal bleeding.

Some patients may experience withdrawal reactions upon stopping desvenlafaxine. Symptoms of withdrawal include anxiety, nausea, nervousness, and insomnia. The dose of desvenlafaxine should be gradually reduced when therapy is discontinued to prevent symptoms of withdrawal.

Antidepressants increased the risk of suicidal thinking and behavior (suicidality) in short-term studies in children and adolescents with depression and other psychiatric disorders. Anyone considering the use of desvenlafaxine or any other antidepressant in a child or adolescent must balance this risk with the clinical need. Patients who are started on therapy should be closely observed for clinical worsening, suicidality, or unusual changes in behavior.

The recommended dose of desvenlafaxine is 50 mg daily, with or without food. Tablets should be taken whole and should not be crushed, divided, chewed, or dissolved. Doses greater than 50 mg are not more effective but cause more side effects.

All SNRIs, including desvenlafaxine, should not be taken with any of the monoamine oxidase inhibitor (MAOI) class of antidepressants, for example, isocarboxazid (Marplan), phenelzine (Nardil), tranylcypromine (Parnate), selegiline (Eldepryl), and procarbazine (Matulane) or other drugs that inhibit monoamine oxidase [for example, linezolid (Zyvox)]. Such combinations may lead to confusion, high blood pressure, tremor, hyperactivity, coma, and death. Desvenlafaxine should not be administered within 14 days after stopping MAOIs and MAOIs should not be administered within 7 days of stopping desvenlafaxine.

Similar reactions may occur if desvenlafaxine is combined with other SNRIs, selective serotonin reuptake inhibitors (for example, fluoxetine [Prozac] or paroxetine [Paxil]) or other drugs that increase serotonin in the brain, for example, tryptophan, St. John's wort, meperidine (Demerol) or tramadol (Ultram).

SNRIs may increase the effect of warfarin (Coumadin), leading to excessive bleeding. Warfarin therapy should be monitored more frequently in patients who are also taking desvenlafaxine. Combining SNRIs with aspirin, nonsteroidal antiinflammatory drugs (NSAIDs) or other drugs that affect bleeding may increase the likelihood of upper gastrointestinal bleeding.

Ketoconazole (Nizoral, Extina, Xolegel, Kuric) may reduce the breakdown of desvenlafaxine, therefore increasing concentrations of desvenlafaxine in the body and the risk of adverse effects. Desvenlafaxine may reduce the concentration of midazolam (Versed).

Desvenlafaxine is secreted in breast milk. Mothers who are taking desvenlafaxine should discuss with their doctor whether to not breastfeed or to discontinue desvenlafaxine.

What preparations of desvenlafaxine (Pristiq) are available?

Tablets (extended release): 50 and 100 mg

How should I keep desvenlafaxine (Pristiq) stored?

Tablets should be kept at room temperature, 20 C and 25 C (68 F and 77 F).