Efexor (Venlafaxine) Side Effects in Pakistan

Complete guide to Efexor (Venlafaxine) side effects — from common effects to serious warnings, with special focus on discontinuation syndrome and BP elevation, which are the distinguishing features of this medicine.

Compiled by the PakVita Editorial Team · AI-assisted drafting with editorial review · Sourced from DRAP, WHO, BNF · Last updated: 2026-06-17

Side Effects

Quick Answer

Efexor (Venlafaxine) common side effects include nausea, dry mouth, sweating, sleep disturbance, and sexual dysfunction. Serious risks include rising blood pressure, serotonin syndrome, and severe discontinuation syndrome (if stopped abruptly). Never stop abruptly.

Side Effects at a Glance

Common

Nausea (matli) — especially very common in the first few weeks
Dry mouth (muh sukhna)
Sweating (pasina) — common
Headache (sar dard)
Insomnia
Sexual dysfunction (jinsee masail — delay, anorgasmia)
Constipation (qabz)
Dizziness (chakkar)
Tremor (kaanpna)
Blood pressure elevation (BP barhna — dose-dependent)

Serious — See a Doctor

Serotonin syndrome — agitation, high fever, tremor, confusion
Severe hypertension / hypertensive urgency (dose-dependent)
QT prolongation / cardiac arrhythmia
Hyponatraemia / SIADH
Bleeding risk — antiplatelet effect
Mania activation
Severe discontinuation syndrome (if stopped abruptly — brain zaps, dizziness, nausea, electric shock sensations)
Suicidal ideation
Seizures (rare, at high doses)

When to See a Doctor Immediately

Thoughts of self-harm or suicide — immediately call 1122 or nearest emergency
Agitation, high fever, trembling — signs of serotonin syndrome
Severe headache, visual disturbance, chest pain — hypertensive urgency
Brain zaps, severe dizziness, nausea — if medication was stopped abruptly
Irregular heartbeat
Swelling in the eyes, hands, or feet

Efexor (Venlafaxine) Side Effects (Nuksanat)

Efexor (Venlafaxine) is an effective SNRI antidepressant but has certain distinctive side effects — particularly discontinuation syndrome and blood pressure elevation — that set this medicine apart from other antidepressants.

Common Side Effects (Aam Nuksanat)

Nausea (matli) — especially at the start — reduced by taking with food
Dry mouth (muh sukhna)
Sweating (pasina) — often improves over time
Headache (sar dard)
Insomnia
Sexual dysfunction
Constipation (qabz)
Dizziness (chakkar)
Tremor
Blood pressure elevation (BP barhna)

These side effects often begin to improve in the first few weeks. If they continue, inform your doctor.

Serious Side Effects (Sanjeedah Nuksanat)

Serotonin syndrome — with MAO inhibitors — see a doctor immediately
Severe hypertension — dose-dependent — see a doctor immediately
QT prolongation / cardiac arrhythmia — see a doctor immediately
Hyponatraemia / SIADH — especially in the elderly — see a doctor immediately
Severe discontinuation syndrome — if stopped abruptly: "brain zaps", dizziness, nausea — see a doctor immediately
Suicidal ideation — especially under age 25 — immediately seek emergency or doctor

When to See a Doctor (Kab Doctor Se Milna Zaroori Hai)

Thoughts of self-harm or suicide — seek help IMMEDIATELY
Agitation + high fever + trembling (serotonin syndrome) — IMMEDIATELY
Severe headache + visual disturbance (hypertensive urgency) — IMMEDIATELY
Brain zaps or severe dizziness if stopped abruptly — IMMEDIATELY

Reporting Side Effects

If you notice any unexpected side effect, report it on the DRAP pharmacovigilance portal: https://www.dra.gov.pk/pharmacovigilance

Side Effects Summary Table

Type	Side Effect	Action
Common	Nausea	Take with food; monitor
Common	Sexual dysfunction	Discuss with doctor
Common	BP elevation	Regular BP check
Serious	Serotonin syndrome	IMMEDIATELY seek doctor/emergency
Serious	Discontinuation syndrome	Never stop abruptly
Serious	Suicidal ideation	IMMEDIATELY call 1122 or doctor

The information in this guide is for educational purposes only. If you notice any side effect, contact your doctor or pharmacist.

Frequently Asked Questions

Venlafaxine se matli (nausea) kitne waqt tak rehti hai?

Nausea is usually most intense in the first 1–2 weeks and then improves. Taking it with food and using the XR formulation can reduce it. If it is severe, inform your doctor.

Kya Venlafaxine BP barha sakta hai?

Yes — venlafaxine inhibits norepinephrine reuptake which can raise BP, especially at higher doses (225mg+ per day). Regular BP monitoring during treatment is therefore necessary.

Venlafaxine ka discontinuation syndrome kya hota hai?

Stopping venlafaxine abruptly can cause 'brain zaps', severe dizziness, nausea, electric shock feelings, and anxiety. This is more severe than with SSRIs. Always taper under medical supervision.

Kya Venlafaxine jinsee masail (sexual dysfunction) karta hai?

Yes — sexual dysfunction is a common side effect. If it is bothersome, discuss with your doctor — dose adjustment or alternative medication is possible.

Agar Venlafaxine le rahe hain to kaunsi dawaein saath nahin leni chahiye?

MAO inhibitors (phenelzine, selegiline) ABSOLUTELY NOT — they can cause fatal serotonin syndrome. Tramadol, lithium, and other serotonergic medications should also be taken under medical supervision. Bleeding risk increases with NSAIDs or anticoagulants.

Brand alternatives, same-class options, and other medicines used for the same conditions as Efexor Tablet.

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Used for the same conditions

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Sources

DRAP Registered Products Database — Drug Regulatory Authority of Pakistan
WHO Model List of Essential Medicines, 23rd ed. (2023) — World Health Organization
British National Formulary (BNF) — BMJ Group & Pharmaceutical Press

Medical disclaimer

This page is for educational use only and does not replace professional medical advice. Always confirm diagnosis, dose, and interactions with a qualified doctor or pharmacist before starting or changing any medicine.