Pristiq (desvenlafaxine) is an antidepressant belonging to a group of drugs called selective serotonin and norepinephrine reuptake inhibitors (SNRIs). Desvenlafaxine affects chemicals in the brain that may be unbalanced in people with depression.

Pristiq is used to treat major depressive disorder.

Pristiq may also be used for purposes not listed in this medication guide.

You should not take Pristiq if you are allergic to desvenlafaxine or venlafaxine (Effexor).

Do not use Pristiq within 7 days before or 14 days after you have used an MAO inhibitor, such as isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, or tranylcypromine. A dangerous drug interaction could occur.

Some medicines can interact with desvenlafaxine and cause a serious condition called serotonin syndrome. Be sure your doctor knows if you also take stimulant medicine, opioid medicine, herbal products, or medicine for depression, mental illness, Parkinson's disease, migraine headaches, serious infections, or prevention of nausea and vomiting. Ask your doctor before making any changes in how or when you take your medications.

Some young people have thoughts about suicide when first taking an antidepressant. Your doctor should check your progress at regular visits. Your family or other caregivers should also be alert to changes in your mood or symptoms.

It is important that your doctor check your progress at regular visits, to allow for changes in your dose and to help reduce any side effects. Blood and urine tests may be needed to check for any unwanted effects.

Do not take desvenlafaxine with a monoamine oxidase (MAO) inhibitor (eg, isocarboxazid [Marplan®], phenelzine [Nardil®], selegiline [Eldepryl®], tranylcypromine [Parnate®]). Do not start taking desvenlafaxine within 14 days after you stop using an MAO inhibitor. Wait 7 days after stopping desvenlafaxine before you start taking an MAO inhibitor. If you take them together or do not wait the proper amount of time, you may develop confusion, agitation, restlessness, stomach or bowel symptoms, a sudden high body temperature, an extremely high blood pressure, or severe seizures.

Do not take any medicine that contains venlafaxine (Effexor®) while you are using Khedezla® or Pristiq®.

Get emergency medical help if you have signs of an allergic reaction to Pristiq: skin rash or hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), more depressed, or have thoughts about suicide or hurting yourself.

Call your doctor at once if you have:

- A seizure (convulsions);

- Easy bruising or bleeding (nosebleeds, bleeding gums), blood in your urine or stools, coughing up blood;

- Blurred vision, eye pain or swelling, or seeing halos around lights;

- Cough, chest discomfort, trouble breathing; or

- Low levels of sodium in the body - headache, confusion, severe weakness, memory problems, feeling unsteady, hallucinations.

What is this medicine?

Pristiq ER (Desvenlafaxine) is used to treat depression.

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

Where should I keep my medicine?

Keep out of the reach of children.

Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F). Throw away any unused medicine after the expiration date.