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PRISTIQ (desvenlafaxine succinate) Warnings And Precautions

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Warnings And Precautions


Pediatrics: Placebo-Controlled Clinical Trial Data

Recent analyses of placebo-controlled clinical trial safety databases from Selective Serotonin Reuptake Inhibitors (SSRIs) and other newer anti-depressants suggest that use of these drugs in patients under the age of 18 may be associated with behavioural and emotional changes, including an increased risk of suicidal ideation and behaviour over that of placebo.

The small denominators in the clinical trial database, as well as the variability in placebo rates, preclude reliable conclusions on the relative safety profiles among the drugs in the class.

PRISTIQ is not indicated for use in pediatric patients (see INDICATIONS)

Adults and Pediatrics: Additional data

There are clinical trial and post-marketing reports with SSRIs and other newer antidepressants, in both pediatrics and adults, of severe agitation-type adverse events coupled with self-harm or harm to others. The agitation-type events include: akathisia, agitation, disinhibition, emotional lability, hostility, aggression, depersonalization. In some cases, the events occurred within several weeks of starting treatment. Rigorous clinical monitoring for suicidal ideation or other indicators of potential for suicidal behaviour is advised in patients of all ages especially when initiating therapy or during any change in dose or dosage regimen. This includes monitoring for agitation-type emotional and behavioural changes.

An FDA meta-analysis of placebo-controlled clinical trials of antidepressant drugs in adult patients ages 18 to 24 years with psychiatric disorders showed an increased risk of suicidal behaviour with antidepressants compared to placebo.


Aggression may occur in some patients who have received antidepressants, including desvenlafaxine treatment, dose reduction, or discontinuation. As with other antidepressants, desvenlafaxine should be used cautiously in patients with a history of aggression.


Discontinuation effects are well known to occur with antidepressants, and sometimes these effects can be protracted and severe (see ADVERSE REACTIONS). Suicide/suicidal thoughts and aggression have been observed in patients during changes in desvenlafaxine dosing regimen, including during discontinuation (see WARNINGS AND PRECAUTIONS, Discontinuation Effects). It is therefore recommended that the dosage of desvenlafaxine be tapered gradually and individually and the patients be closely monitored during discontinuation (see DOSAGE AND ADMINISTRATION). In some patients, discontinuation could take months or longer.

Sexual Dysfunction

Serotonin-norepinephrine reuptake inhibitors (SNRIs) may cause symptoms of sexual dysfunction (see ADVERSE REACTIONS). There have been reports of long-lasting sexual dysfunction where the symptoms have continued despite discontinuation of SNRIs.


Concomitant Use of PRISTIQ with VENLAFAXINE

Since desvenlafaxine is the major active metabolite of venlafaxine, concomitant use of PRISTIQ with products containing Venlafaxine is not recommended since the combination of the two will lead to additive desvenlafaxine exposure.

Allergic Reactions

Patients should be advised to notify their physician if they develop a rash, hives or a related allergic phenomenon.

Bone Fracture Risk

Epidemiological studies show an increased risk of bone fractures following exposure to some antidepressants, including SSRIs/SNRIs. The risks appear to be greater at the initial stages of treatment, but significant increased risks were also observed at later stages of treatment. The possibility of fracture should be considered in the care of patients treated with PRISTIQ. Elderly patients and patients with important risk factors for bone fractures should be advised of possible adverse events which increase the risk of falls, such as dizziness and orthostatic hypotension, especially at the early stages of treatment but also soon after withdrawal. Preliminary data from observational studies show association of SSRIs/SNRIs and low bone mineral density in older men and women. Until further information becomes available, a possible effect on bone mineral density with long term treatment with SSRIs/SNRIs, including PRISTIQ, cannot be excluded, and may be a potential concern for patients with osteoporosis or major risk factors for bone fractures.

Carcinogenesis and Mutagenesis

For animal data see TOXICOLOGY.


Caution is advised in administering PRISTIQ to patients with cardiovascular, cerebrovascular, or lipid metabolism disorders (see Clinical Trial Adverse Drug Reactions). Increases in blood pressure and heart rate were observed in clinical trials with PRISTIQ. PRISTIQ has not been evaluated systematically in patients with a recent history of myocardial infarction, unstable heart disease, uncontrolled hypertension, or cerebrovascular disease. Patients with these diagnoses, except for cerebrovascular disease, were excluded from clinical trials.

Effects on blood pressure
Cases of elevated blood pressure requiring immediate treatment have been reported with desvenlafaxine in postmarketing experience, including reports of hypertensive crisis and malignant hypertension. Increases in blood pressure were observed in some patients in clinical trials, particularly with higher doses. Caution should be exercised in treating patients with underlying conditions that might be compromised by increases in blood pressure (see ADVERSE REACTIONS, Vital Sign Changes). Pre-existing hypertension should be controlled before treatment with PRISTIQ. Patients receiving PRISTIQ should have regular monitoring of blood pressure. Sustained blood pressure increases could have adverse consequences. For patients who experience a sustained increase in blood pressure while receiving PRISTIQ, either dose reduction or discontinuation should be considered.

Treatment with PRISTIQ at all doses from 50 mg/day to 400 mg/day in controlled studies was associated with sustained hypertension (defined as treatment-emergent supine diastolic blood pressure ≥ 90 mm Hg and ≥10 mm Hg above baseline for 3 consecutive visits). Table 1 provides the incidence of patients meeting criteria for sustained hypertension.

Table 1: Incidence (%) of Patients with Sustained Hypertension for All Short-Term Fixed-Dose Clinical Trials
    ----------------------- PRISTIQ--------------------
  Placebo 50 mg 100 mg 200 mg 400 mg
Sustained hypertension 0.5 1.3 0.7 1.1 2.3


Although desvenlafaxine succinate has not been systematically studied in preclinical or clinical trials for its potential for abuse, no indication of drug-seeking behavior was seen in the clinical trials.

Discontinuation Symptoms

At the time that a medical decision is made to discontinue PRISTIQ, a gradual reduction in the dose, rather than an abrupt cessation, is recommended.

During marketing of SNRIs, and SSRIs, there have been post-marketing reports of adverse events occurring upon discontinuation of these drugs, particularly when abrupt, including the following: dysphoric mood, irritability, agitation, dizziness, sensory disturbances (e.g., paraesthesias, such as electric shock sensations), anxiety, confusion, headache, lethargy, emotional lability, insomnia, hypomania, tinnitus, seizures, visual impairment and hypertension. While these events are generally self-limiting, there have been reports of serious discontinuation symptoms and sometimes these effects can be protracted and severe. In addition, suicide/suicidal thoughts and aggression have been observed in patients during changes in desvenlafaxine dosing regimen, including during discontinuation.

Patients should be monitored for these symptoms when discontinuing treatment with PRISTIQ. A gradual reduction in the dose rather than abrupt cessation is recommended whenever possible. If intolerable symptoms occur following a decrease in the dose or upon discontinuation of treatment, then resuming the previously prescribed dose may be considered. Subsequently, the physician may continue decreasing the dose but at a more gradual rate (see ADVERSE REACTIONS, Discontinuation Symptoms, and DOSAGE AND ADMINISTRATION, Discontinuing PRISTIQ). In some patients, discontinuation may need to occur over periods of months or longer.

Endocrine and Metabolism

Serum Cholesterol Elevation
Increases in cholesterol (total and LDL) and triglycerides were observed in some patients treated with desvenlafaxine succinate in placebo-controlled pre-marketing clinical trials, particularly with higher doses. Measurement of serum lipid levels should be considered during treatment.

Cases of hyponatremia and/or the Syndrome of Inappropriate Antidiuretic Hormone (SIADH) secretion have been described with SNRIs and SSRIs, usually in volume-depleted or dehydrated patients, including elderly patients and patients taking diuretics.


Potential for Gastrointestinal Obstruction
Because the PRISTIQ tablet does not appreciably change in shape in the gastrointestinal tract, PRISTIQ should not be administered to patients with pre-existing gastrointestinal narrowing (pathologic or iatrogenic, such as small bowel inflammatory disease, “short gut” syndrome due to adhesions or decreased transit time, past history of peritonitis, cystic fibrosis, chronic intestinal pseudo-obstruction, or Meckel’s diverticulum). There have been rare reports of obstructive symptoms in patients with known strictures in association with the ingestion of other drugs in nondeformable controlled-release formulations, and very rare reports of obstructive symptoms associated with the use of nondeformable controlled-release formulations in patients without known gastrointestinal stricture. Due to the controlled-release design, PRISTIQ tablets should only be used in patients who are able to swallow the tablets whole. (See DOSAGE AND ADMINISTRATION; Recommended Dose and Dosage Adjustment).


Abnormal Bleeding
SSRIs and SNRIs, including PRISTIQ, may increase the risk of bleeding events by causing abnormal platelet aggregation. Concomitant use of acetylsalicylic acid (ASA), nonsteroidal anti-inflammatory drugs (NSAIDs), warfarin and other anticoagulants may add to the risk. Case reports and epidemiological studies (case-control and cohort design) have demonstrated an association between use of drugs that interfere with serotonin reuptake and the occurrence of gastrointestinal bleeding. Bleeding events related to SSRIs and SNRIs use have ranged from ecchymoses, hematomas, epistaxis, and petechiae to life-threatening hemorrhages.

Patients should be cautioned about the risk of bleeding associated with the concomitant use of PRISTIQ and NSAIDs, ASA, or other drugs that affect coagulation (see DRUG INTERACTIONS, Drugs Affecting Platelet Function). Caution is advised in patients with a history of bleeding disorder or predisposing conditions (e.g, thrombocytopenia).

Interstitial Lung Disease and Eosinophilic Pneumonia

Interstitial lung disease and eosinophilic pneumonia associated with venlafaxine (the parent drug of PRISTIQ) therapy have been rarely reported. The possibility of these adverse events should be considered in patients treated with PRISTIQ who present with progressive dyspnea, cough, or chest discomfort. Such patients should undergo a prompt medical evaluation, and discontinuation of PRISTIQ should be considered.


Cases of seizures have been reported in trials with PRISTIQ. Desvenlafaxine succinate should be prescribed with caution in patients with a seizure disorder. Desvenlafaxine has not been systematically evaluated in patients with a seizure disorder.

Serotonin Syndrome or Neuroleptic Malignant Syndrome (NMS)-Like Reactions
As with other serotonergic agents, serotonin syndrome or Neuroleptic Malignant Syndrome (NMS)-like reactions, a potentially life-threatening condition, have been reported with SNRIs and SSRIs alone, including PRISTIQ treatment, particularly with concomitant use of other agents that may affect the serotonergic neurotransmitter systems (such as amphetamines, triptans, serotonin reuptake inhibitors, sibutramine, MAOIs (including linezolid, an antibiotic, and methylene blue), St. John’s Wort (Hypericum perforatum) and/or lithium) and with drugs that impair metabolism of serotonin or with antipsychotics or other dopamine antagonists. Serotonin syndrome symptoms may include mental status changes (e.g., agitation, hallucinations, and coma), autonomic instability (e.g., tachycardia, labile blood pressure, and hyperthermia), neuromuscular aberrations (e.g., hyperreflexia, incoordination) and/or gastrointestinal symptoms (e.g., nausea, vomiting, and diarrhea). Serotonin syndrome, in its most severe form, can resemble NMS, which includes hyperthermia, muscle rigidity, autonomic instability with possible rapid fluctuation of vital signs, and mental status changes.

If concomitant treatment with desvenlafaxine and other agents that may affect the serotonergic and/or dopaminergic neurotransmitter system (such as another SSRI/SNRI) or a 5-hydroxytryptamine receptor agonist (triptan) is clinically warranted, careful observation of the patient is advised, particularly during treatment initiation and dose increases. The concomitant use of desvenlafaxine with serotonin precursors (such as tryptophan supplements) is not recommended (see DRUG INTERACTIONS, Serotonin Syndrome).

Treatment with PRISTIQ and any concomitant serotonergic or antidopaminergic agents, including antipsychotics, should be discontinued immediately if the above events occur and supportive symptomatic treatment should be initiated.


Angle-Closure Glaucoma
As with other antidepressants, PRISTIQ can cause mydriasis, which may trigger an angle-closure attack in a patient with anatomically narrow ocular angles. Healthcare providers should inform patients to seek immediate medical assistance if they experience eye pain, changes in vision or swelling or redness in or around the eye.


Mania/hypomania may occur in a small proportion of patients with mood disorders who have received medication to treat depression, including desvenlafaxine succinate. During clinical studies, mania and hypomania were reported in approximately 0.15% (12/8,453) of patients treated with PRISTIQ. Activation of mania/hypomania has also been reported in a small proportion of patients with major affective disorder who were treated with other marketed antidepressants. As with all antidepressants, PRISTIQ should be used cautiously in patients with a history or family history of mania or hypomania.

A major depressive episode may be the initial presentation of bipolar disorder. Patients with bipolar disorder may be at an increased risk of experiencing manic episodes when treated with antidepressants alone. Therefore, the decision to initiate symptomatic treatment of depression should only be made after patients have been adequately assessed to determine if they are at risk for bipolar disorder.

Special Populations

Pregnant Women
The safety of desvenlafaxine in human pregnancy has not been established. Studies have demonstrated that desvenlafaxine crosses the human placenta. The extent of exposure to PRISTIQ in pregnancy during clinical trials was very limited. There are no adequate and well-controlled studies in pregnant women. Therefore, desvenlafaxine should be used during pregnancy only if the potential benefits justify the potential risks. If desvenlafaxine succinate is used until or shortly before birth, discontinuation effects in the newborn should be considered.

Post-marketing reports indicate that some neonates exposed to SNRIs, SSRIs, or other newer antidepressants late in the third trimester have developed complications requiring prolonged hospitalization, respiratory support, and tube feeding. Such complications can arise immediately upon delivery. Reported clinical findings have included respiratory distress, cyanosis, apnea, seizures, temperature instability, feeding difficulty, vomiting, hypoglycemia, hypotonia, hypertonia, hyper-reflexia, tremor, jitteriness, irritability, and constant crying. These features are consistent with either a direct toxic effect of SNRIs, SSRIs and other newer antidepressants, or, possibly a drug discontinuation syndrome. It should be noted that, in some cases, the clinical picture is consistent with serotonin syndrome (see DRUG INTERACTIONS). When treating a pregnant woman with PRISTIQ during the third trimester, the physician should carefully consider the potential risks and benefits of treatment.

Any change in antidepressant medication (including dosage) during pregnancy should be discussed with the attending physician beforehand to discuss the benefits/risks with the patient.  

Exposure to SNRIs in mid to late pregnancy may increase the risk for preeclampsia, and exposure to SNRIs near delivery may increase the risk for postpartum hemorrhage.

Patients should be advised to notify their physician if they become pregnant or intend to become pregnant during therapy.

Labour and Delivery
The effect of desvenlafaxine on labour and delivery in humans is unknown. PRISTIQ should be used during labour and delivery only if the potential benefits justify the potential risks.

Nursing Women
Desvenlafaxine (O-desmethylvenlafaxine, a metabolite of desvenlafaxine) is excreted in human milk. The effects in infants have not been established. PRISTIQ should only be taken by breastfeeding women if the expected benefits outweigh any possible risk.


Based on the data submitted and reviewed by Health Canada, the safety and efficacy of PRISTIQ in pediatric patients has not been established; therefore, Health Canada has not authorized an indication for pediatric use (see WARNINGS AND PRECAUTIONS, Potential Association with Behavioural and Emotional Changes, Including Self-Harm)

Two placebo controlled studies in 587 pediatric patients 7 to 17 years of age with MDD failed to demonstrate efficacy; neither short term, placebo-controlled study demonstrated statistically or clinically significant differences between PRISTIQ and placebo (see ACTION AND CLINICAL PHARMACOLOGY, Pediatrics).

The long-term safety, including effects on growth, maturation, and behavioural development, in patients under 18 years of age has not been systematically evaluated. See ADVERSE REACTIONS, Adverse Drug Reactions in Pediatrics.

Geriatrics (≥ 65 years of age)
Of the 4,158 patients in clinical trials with PRISTIQ, 6% were 65 years of age or older. No overall differences in safety or efficacy were detected between these subjects and younger subjects. However, there was a higher incidence of increases in systolic blood pressure in patients ≥ 65 years of age compared to patients < 65 years of age treated with PRISTIQ. In addition, there was a higher incidence of systolic orthostatic hypotension in patients ≥ 65 years of age compared to all adults treated with desvenlafaxine. For elderly patients, possible reduced renal clearance of desvenlafaxine should be considered when determining dose (see Dosing Considerations, Geriatrics and ACTION AND CLINICAL PHARMACOLOGY, Geriatrics). Greater sensitivity of some older individuals cannot be ruled out.

Monitoring and Laboratory Tests

Serum Lipids
Increases in cholesterol (total and LDL) and triglycerides were observed in some patients treated with desvenlafaxine succinate in placebo-controlled pre-marketing clinical trials, particularly with higher doses. Measurement of serum lipid levels should be considered during treatment.

Heart Rate and Blood Pressure
Increases in heart rate and blood pressure were observed in some patients in clinical trials, particularly with higher doses. Measurement of blood pressure is recommended prior to initiating treatment and regularly during treatment with desvenlafaxine succinate (see ADVERSE REACTIONS, Vital Sign Changes).

Rigorous clinical monitoring for suicidal ideation or other indicators of potential for suicidal behaviour is advised in patients of all ages. Patients, their families, and their caregivers should be encouraged to be alert to the emergence of anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia (psychomotor restlessness), hypomania, mania, other unusual changes in behavior, worsening of depression, and suicidal ideation, especially when initiating therapy or during any change in dose or dosage regimen. (See WARNINGS AND PRECAUTIONS, POTENTIAL ASSOCIATION WITH BEHAVIOURAL AND EMOTIONAL CHANGES, INCLUDING SELF-HARM).

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