Disclaimer: None of the information in this article constitutes medical advice, and is just the opinion of the writer(s). We recommend that patients follow their doctor’s guidance in regard to prescription medication.
Pristiq is an FDA-approved medication that's used to treat major depressive disorder (MDD). The generic version of Pristiq is desvenlafaxine, and we will use these terms interchangeably throughout this article because they refer to the same active drug ingredient.
But is Pristiq more effective than other antidepressants? Does it cause serious side effects? Does it cause withdrawals? And how much cheaper is the generic version?
In this article we’ll answer all of these questions and more, as we review research studies on Pristiq to determine if it's effective against depression.
We'll also document the drug's side effects, analyze whether or not Pristiq is effective for anxiety, and explain if the generic version of the drug is a better option.
Key takeaways:
- Decreased depression symptoms by more than 50% in one trial
- Can cause severe side effects (particularly in children and young adults)
- Clinically shown to relieve anxiety as well
Does Pristiq Relieve Depression?
Pristiq has been studied in various clinical trials testing its effects in patients with depression.
A clinical trial published in the CNS Spectrums journal found that Pristiq was effective in patients with depression.
Researchers in the trial measured patient symptoms on the Hamilton Depression Rating Scale (HAM-D), which tracks patient responses across a wide variety of symptoms associated with depression, such as insomnia and loss of sex drive.
Depressed patients taking Pristiq experienced significantly reduced HAM-D scores.
The average HAM-D score was over 20 at the start of the trial and under 10 at the end of the trial, representing a decrease in depression symptoms of greater than 50%.
A 2010 meta-study evaluated the efficacy of Pristiq in patients with major depressive disorder.
The study authors concluded that Pristiq was safe, effective and tolerable in severely depressed patients and improved their condition.
Remission rates were around 10% higher in the groups taking Pristiq compared to the groups taking placebo pills.
Remission is defined as an extended period free of any major depressive symptoms.
We will conclude from the available research that Pristiq is effective for treating depression, which is unsurprising given that it's approved for that indication by the FDA.
Does Pristiq Cause Side Effects?
Pristiq is required by the FDA to publish a “black box” warning on its drug label, shown below, which references an increased risk of suicidal behavior in children, adolescents and young adults:
A clinical trial published in the Current Medical Research and Opinion journal reported on more common side effects caused by Pristiq.
Dry mouth occurred 9% more often in those taking Pristiq than in those taking placebo, dizziness occurred 8% more often and constipation occurred 7% more often.
Most of the common side effects of Pristiq seem relatively mild and standard for antidepressant drugs, but it may be logical for young adult patients to speak with their doctor about alternative antidepressant drugs that do not increase the risk of suicidal thoughts or actions.
How Much Cheaper is the Generic?
The generic form of Pristiq is called desvenlafaxine.
A medical review on the comparative effectiveness of generic and branded drugs found that the generic versions were just as effective on average.
This suggests that desvenlafaxine should be as effective as Pristiq, but may be much cheaper.
We typically recommend that patients speak with their doctor about generic alternatives to brand-name drugs due to the retail price difference.
At the time of updating this article, the retail price of Pristiq is currently around $200 according to GoodRx.
The retail price of generic desvenlafaxine is currently under $20 at Cost Plus Drugs.
Does Pristiq Cause Withdrawals?
Like many pharmaceutical antidepressant medications, Pristiq does have a risk of uncomfortable withdrawal symptoms.
A 2009 research review documented these symptoms in order of occurrence. The most common withdrawal symptoms were similar to the most common Pristiq side effects: dizziness, nausea, headache and irritability.
Patients taking higher doses experienced worse withdrawal symptoms.
After week three, patients withdrawing from a 400 milligram (mg) per day dose were still experiencing withdrawal symptoms around 100% more severe than patients withdrawing from a 100 mg per day dose.
Withdrawal symptoms can be mitigated with proper tapering, which means a strategic lowering of dose rather than stopping medication all at once.
This is why it’s so important for patients to speak with their doctor prior to discontinuing Pristiq.
Even if the patient is set on quitting the medication, their doctor can help them taper off safely based on research standards which reduce the risk of withdrawals.
Does Pristiq Reduce Anxiety?
Pristiq is not FDA-approved for the treatment of anxiety, but there have been some clinical trials evaluating the drug's effects on anxiety levels in depressed patients.
A meta-study published in the CNS Spectrums journal analyzed results from nine clinical trials on Pristiq to examine its effects on anxiety.
Study participants taking Pristiq experienced significantly reduced anxiety.
Anxiety scores were 14% lower in those taking Pristiq than in those taking placebo pills.
Another medical study found similar results. Depressed patients taking Pristiq had significantly reduced anxiety levels by the end of the trial.
These studies suggest that Pristiq may be an effective option for patients with both depression and anxiety.
They don’t prove that Pristiq is effective in non-depressed patients suffering from anxiety, because the patient populations in both studies were depressed.
Pristiq vs. Effexor
As we documented in our Effexor reviews article, the antidepressant Effexor is in the same drug class as Pristiq (SNRI). For this reason, patients are often curious about which drug is more effective for depression.
A comparative study published in the CNS Spectrums journal analyzed the effectiveness and safety of the two drugs.
Pristiq reduced depression scores by a small amount more than Effexor in the above-linked review, but not to a statistically significant degree. Pristiq also caused fewer patients to experience nausea as a side effect.
The active ingredient in Pristiq is a metabolite of the active ingredient in Effexor, so it's unsurprising that the two drugs have very similar effects.
Because the drug appears slightly more effective and seems to have a slightly more favorable side effect profile, we would recommend that patients speak with their doctor about Pristiq over Effexor.
How Does Pristiq Work?
Pristiq is in a drug class called SNRI, or serotonin and norepinephrine reuptake inhibitor.
According to a 2023 medical review, Pristiq is 10 times more selective for serotonin than norepinephrine.
This class of drugs delays the body’s processing of neurotransmitters serotonin and norepinephrine which has significant effects on mood. In Pristiq’s case, it has more of an effect on serotonin than norepinephrine based on the above-linked research review.
By blocking normal processing and clearance of these neurotransmitters, Pristiq causes an artificial increase in their circulating levels in the brain, which can improve mood and relieve symptoms of depression.
It hasn’t been conclusively proven that patients with depression have lower levels of serotonin or norepinephrine than neurotypical patients, but this is the suggested mechanism of action.
Pristiq Dosage
Pristiq is prescribed at different doses depending on the severity of the patient's depression. The therapeutic dosing range is between 25 mg and 400 mg. The typical starting dose is 50 mg.
A clinical trial compared the efficacy of Pristiq at 50 mg per day and 100 mg per day.
Contrary to what one might expect, Pristiq was actually more effective at the lower dose. Patients on the 50 mg daily dose experienced greater average reduction in depression scores than patients on the 100 mg daily dose by the end of the trial.
Typically there is a trade off between efficacy and side effects. The higher the dose, the higher the chance of side effects. Since Pristiq appears to be more effective at a lower dose, at least according to one research trial, this should be a good thing for patients because it may lower the risk of side effects.
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