Does Pristiq cause loss of appetite? (+3 studies)

In this article, we will discuss whether Pristiq causes a loss of appetite. We will also discuss the possible mechanisms through which Pristiq affects appetite, evidence from research, the impact of doses and duration of treatment on appetite and other relevant information. 

Does Pristiq cause loss of appetite? 

Yes, Pristiq can cause loss of appetite in some individuals. Decreased appetite is an officially documented side effect of Pristiq and is commonly reported by patients. Pristiq is the brand name for desvenlafaxine and is an antidepressant drug. 

Pristiq or desvenlafaxine is a serotonin-norepinephrine reuptake inhibitor (SNRI) and increases serotonin and norepinephrine (NE) levels in the brain. It is FDA-approved to treat major depressive disorder (MDD) (1). 

Decreased appetite is a frequently reported side effect of Pristiq. It is however temporary and likely to resolve within a few weeks. If you experience persistent reduced appetite while taking Pristiq, contact your healthcare provider. 

How does Pristiq cause loss of appetite?

Pristiq works by increasing the levels of serotonin and NE in the body. Serotonin plays several roles in different body systems along with the central nervous system. Serotonin plays a role in reducing appetite and nutrient intake in the body (2). 

Appetite regulation is mainly controlled by the hypothalamus where different groups of cells increase or decrease the appetite. One group of cells produces proopiomelanocortin (POMC) which is a large protein molecule (2). 

POMC neurons activate certain receptors which reduce appetite and nutrient intake. Another protein called agouti-related peptide (AgRP) is also produced in the hypothalamus which increases appetite and food intake (2). 

Serotonin results in appetite suppression because it stimulates POMC neurons and inhibits AgRP neurons in the hypothalamus. Studies on rats have shown that rats lacking serotonin have increased appetite and are at risk for obesity (2). 

Thus, the role of serotonin in reducing appetite and nutrient intake is well-established in the literature. As Pristiq increases serotonin levels in the body, it causes the side effect of decreased appetite in individuals. 

What does research suggest?

The side effect of reduced appetite while taking Pristiq has been frequently reported. A systematic review of several clinical trials was conducted to study the efficacy, safety, and tolerability of desvenlafaxine the active ingredient in Pristiq (3). 

In the review mentioned above, patients received desvenlafaxine at a dose of 50mg/day. Decreased appetite was reported by many patients as a side effect in every clinical trial included in this review (3). 

Another article reviewed the published studies on the effectiveness and safety of desvenlafaxine, the active ingredient of Pristiq. Results mention that decreased appetite was reported as a side effect and associated with weight loss in patients (4). 

One long-term study was carried out to evaluate the effects of desvenlafaxine in 1395 patients. Reduced appetite was included in the side effects experienced by at least 5% of the population in this study (5). 

How does Pristiq dosage and duration of treatment affect appetite? 

Side effects of Pristiq depend on the dose you are taking. Higher doses are associated with heightened side effects. Pristiq at the dose of 50mg/day is safe and well tolerated. Side effects occur in the first week and are resolved afterwards (3). 

In different studies, patients taking a higher dose of Pristiq report a decreased appetite more frequently. In one clinical trial, the number of patients reporting reduced appetite was 16 at 50mg/day and 33 at 400 mg/day (3). 

Thus, you are more likely to experience reduced appetite if you are taking higher doses of Prsitiq. Different studies have shown that Pristiq is safe and effective for long-term use (4,5). 

A 10-month study on desvenlafaxine, the active ingredient in Pristiq reported that higher doses had a similar safety profile as a 50mg/day dose. Rates of discontinuation due to adverse effects were higher in patients taking higher doses (5). 

Thus, it can be concluded that the side effect of reduced appetite is likely to be resolved within a few weeks of treatment at the initial recommended dose of Pristiq which is 50 mg/day. 

Long-term treatment with Pristiq at the dose of 50mg/day is generally safe and well-tolerated. At higher doses, Pristiq causes heightened side effects which may persist for a longer duration. 

Long-term treatment with higher doses of Pristiq is associated with increased risks of discontinuation. It is important to note that increased doses of Pristiq are as effective as a 50mg dose and do not offer more advantages. 

What to do if Pristiq causes reduced appetite? 

If you observe a reduced appetite while taking Pristiq, it’s likely to go away within a few weeks. However, if it persists, contact your healthcare provider. Don’t cut the tablet in half for dose reduction or stop taking the medicine abruptly. 

Your healthcare provider may consider dose reduction to resolve the side effect of decreased appetite. If it persists, your healthcare provider may consider alternative treatments. If you are taking Pristiq for MDD, other treatment options include (6):

  • selective serotonin reuptake inhibitors (SSRIs) like sertraline and fluoxetine
  • serotonin modulators like trazodone
  • other SNRIs like venlafaxine and duloxetine 

How to avoid the consequences of reduced appetite while taking Pristiq?

A reduced appetite decreases your food intake which may result in nutrient deficiency. While taking Pristiq, you may find yourself eating less proper meals which deprives your body of essential nutrients. 

These nutrients like carbohydrates, proteins, fats, minerals, and vitamins are required for normal functioning, growth, development and overall health. You can also experience weight loss while taking Pristiq due to reduced appetite. 

To avoid nutrient deficiency, you can include meals in your diet that are rich in nutrients and calories. Include proteins, healthy fats, nuts, fruits, and vegetables in your meals that will provide nutrients and calories without needing large portions.

If you don’t want to eat large portions of meals you can break down your meals into smaller portions that you eat throughout the day. You can also include healthy snacks like yoghurt and whole-grain crackers that are lightweight but nutritious. 

Thus, focus on consuming sufficient nutrients even if your meal portions are reduced. Be mindful of what you eat, and regularly check your weight on a weighing machine. 

What are some other side effects of Pristiq?

Some commonly reported side effects of Pristiq along with reduced appetite include (3):

  • sweating
  • dry mouth
  • dizziness
  • nausea
  • constipation
  • fatigue
  • insomnia
  • drowsiness

In my perspective, Pristiq causes a loss of appetite in individuals. Reduced appetite is an officially documented and frequently reported side effect of Pristiq. Pristiq reduces appetite by increasing serotonin levels and serotonin plays a direct role in appetite suppression and the reduction of nutrient intake. The occurrence of reduced appetite while taking Pristiq is widely reported in the literature. Individuals taking higher doses of Pristiq are more likely to experience reduced appetite for a longer duration. You must contact your healthcare provider if you experience persistent appetite loss while taking Pristiq. 

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