PRISTIQ 50MG TAB

Indications

Approved Uses

Major Depressive Disorder (MDD) in adults

Off-Label Uses

Off-label uses with some evidence include menopausal vasomotor symptoms (hot flashes) and certain anxiety disorders (e.g., GAD); evidence for neuropathic pain/fibromyalgia is less consistent and not routinely recommended compared with other SNRIs.

Dosage & Administration

Dosing by Condition

Major Depressive Disorder (adults): 50 mg orally once daily (recommended starting and maintenance dose). Doses up to 400 mg/day have been studied, but no additional benefit over 50 mg/day was demonstrated and adverse effects increase; use higher doses only if clinically justified.

Initial Dose

50mg once daily.

Maintenance Dose

50mg once daily.

Maximum Dose

400mg per day, though doses above 50mg/day are not recommended as they do not provide additional benefit.

Children's Dosage

Not approved for children or adolescents under 18 years

Dose Adjustment Notes

Renal impairment: adjust dose-severe renal impairment (CrCl <30 mL/min) or ESRD: 50 mg every other day; do not give supplemental doses after dialysis. Hepatic impairment: generally no adjustment for mild/moderate; use caution in severe hepatic impairment and avoid higher doses. Discontinuation: taper gradually when stopping to reduce discontinuation symptoms.

How to Take

Swallow the extended-release tablet whole with water (or other fluid); do not crush, chew, split, or dissolve. May be taken with or without food. Take once daily at approximately the same time each day.

Side Effects

Common Side Effects

Common adverse effects include nausea, dizziness, insomnia, hyperhidrosis (sweating), constipation, somnolence, decreased appetite, dry mouth, and sexual dysfunction; headache and fatigue are also commonly reported.

Side Effect Frequency

Very common (≥10%): nausea, dizziness, insomnia, hyperhidrosis (increased sweating), dry mouth, constipation. Common (1-<10%): decreased appetite, anxiety, somnolence, fatigue/asthenia, headache, diarrhea, vomiting, tremor, palpitations, blurred vision, sexual dysfunction (e.g., decreased libido, anorgasmia, delayed ejaculation/ejaculatory disorder), increased blood pressure. Uncommon/Rare (generally <1% or post-marketing): hyponatremia/SIADH, serotonin syndrome, seizures, mania/hypomania activation, abnormal bleeding, angle-closure glaucoma.

Safety & Warnings

Contraindications

Contraindicated with MAOIs (concomitant use or within 14 days of stopping an MAOI; and allow at least 7 days after stopping PRISTIQ before starting an MAOI); contraindicated with linezolid or IV methylene blue; contraindicated in patients with hypersensitivity to desvenlafaxine or venlafaxine.

Warnings & Precautions

Key warnings/precautions: boxed warning for suicidality (monitor closely, especially early and in <25); serotonin syndrome risk with serotonergic agents; monitor blood pressure/heart rate; increased bleeding risk with NSAIDs/anticoagulants; hyponatremia/SIADH risk (higher in elderly/diuretics); screen for bipolar disorder/mania risk; seizure risk; angle-closure glaucoma risk; taper to discontinue to reduce withdrawal symptoms.

Age Restriction

Not approved for use in pediatric patients (<18 years).

Drug Interactions

Drug Interactions

Major interactions: MAOIs (contraindicated), linezolid and IV methylene blue (contraindicated); serotonergic drugs (e.g., SSRIs/SNRIs, triptans, tramadol, lithium, St. John’s wort) increase serotonin syndrome risk; drugs affecting hemostasis (NSAIDs/aspirin/anticoagulants incl. warfarin) increase bleeding risk; strong CYP3A4 inhibitors (e.g., ketoconazole) can increase desvenlafaxine exposure; alcohol/CNS depressants may worsen CNS effects; monitor BP with agents that raise BP.

Interaction Severity

MAJOR/Contraindicated: concomitant MAOIs (and within required washout periods); also avoid linezolid or IV methylene blue unless no alternatives due to serotonin syndrome risk. MODERATE: other serotonergic agents (e.g., SSRIs/SNRIs, triptans, tramadol, lithium) due to serotonin syndrome risk; NSAIDs/aspirin/anticoagulants due to increased bleeding risk; monitor with other BP-elevating agents. MINOR: strong CYP3A4 inhibitors (e.g., ketoconazole) cause only modest exposure changes.

Food Interaction

No restriction - can be taken with or without food

Special Populations

Pregnancy

Pregnancy: May cause fetal harm when administered to pregnant women. Risk Summary: There are no adequate and well-controlled studies of PRISTIQ in pregnant women

Children

Not approved for children or adolescents under 18 years

Elderly

No dose adjustment required based solely on age; however, use with caution due to increased risk of hyponatremia, falls, and cardiovascular effects. Monitor blood pressure and sodium levels. Start at 50mg once daily.

Kidney Impairment

CrCl 30-50 mL/min: maximum 50 mg/day; CrCl <30 mL/min or ESRD: 50 mg every other day (no supplemental post-dialysis dose).

Liver Impairment

The recommended dose in patients with hepatic impairment is 50 mg/day. Dose escalation should be done carefully in patients with moderate or severe hepatic impairment

Storage & Patient Advice

Stopping the Medicine

Do not stop abruptly; taper gradually using stepwise dose reductions to minimize discontinuation symptoms (e.g., dizziness, nausea, headache, irritability, insomnia).

Overdose

Possible overdose effects include nausea/vomiting, dizziness, somnolence, tachycardia/hypertension, seizures, and serotonin syndrome; management is supportive (airway/ventilation, cardiac monitoring, treat seizures/serotonin syndrome as needed; consider activated charcoal if early); no specific antidote-seek emergency care.

Patient Counseling

Take 50 mg once daily at the same time each day; swallow the ER tablet whole (do not crush/chew/split/dissolve) and it may be taken with or without food. Do not stop abruptly-taper with your prescriber to avoid discontinuation symptoms (e.g., dizziness, nausea, irritability). Watch for worsening depression or suicidal thoughts (especially early), and seek urgent care for serotonin syndrome symptoms (agitation, confusion, fever, sweating, tremor, diarrhea). Avoid or limit alcohol; use caution driving until you know the effect. Tell your clinician about all medicines, especially other serotonergic drugs and NSAIDs/aspirin/anticoagulants.

Monitoring Requirements

Monitor blood pressure (and consider heart rate) at baseline and periodically; monitor for clinical worsening/suicidality especially early and after dose changes; monitor for serotonin syndrome when combined with serotonergic drugs; consider serum sodium in elderly/at-risk patients (hyponatremia/SIADH); assess renal function when impairment is present or suspected.

Pharmacology

Mechanism of Action

Serotonin-norepinephrine reuptake inhibitor (SNRI) that inhibits reuptake of serotonin and norepinephrine; desvenlafaxine is the active metabolite of venlafaxine.

Duration of Effect

Approximately 24 hours per dose (once-daily dosing); symptomatic improvement is maintained with continued daily therapy, with full antidepressant response typically requiring about 4-8 weeks.

Half-Life

Approximately 11 hours.

Bioavailability

Approximately 80%.

Metabolism

Metabolized mainly by conjugation (glucuronidation/UGT pathways) with minor oxidative metabolism via CYP3A4; it is not a clinically significant CYP inhibitor/inducer.

Excretion

Primarily renal elimination: ~45% excreted unchanged in urine; total urinary recovery is about ~70%.

Protein Binding

Low protein binding, approximately 30%.

Product Information

Available Dosage Forms

Extended-release tablet (prolonged-release tablet)

Composition per Dose

Each extended-release tablet: 76mg desvenlafaxine succinate equivalent to 50mg desvenlafaxine base

Generic Availability

No

OTC Alternatives

No OTC alternative

Psych Class

Antidepressant-SNRI

Controlled Substance

No

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