Venlafaxine

SNRI Very Addictive Some Weight Gain Risk

Sedating: Can be Driving: Caution QT risk: Moderate Akathisia: Moderate Metabolic: Moderate Prolactin: Moderate t½: 12 h Tmax: 6 h

The Marmite antidepressant. Some people swear venlafaxine saved their life, others will never forgive it for the withdrawal alone. It’s an SNRI, so it boosts both serotonin and noradrenaline — which can feel more energising than an SSRI, or just make your anxiety go nuclear at first. At low doses it’s basically an SSRI; higher doses kick in the noradrenaline effect. The downside? Coming off can be brutal: brain zaps, dizziness, nausea, and feeling like gravity itself is broken. Psychiatrists still love it for stubborn depression, but anyone who’s lived through venlafaxine withdrawal won’t forget it in a hurry.

Uses • Warnings

🩺 Main Uses

Depression; anxiety disorders; panic disorder; social anxiety.

🧪 The Science & Facts

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Half‑life (t½)

12 h

How long the drug hangs around. Longer half‑life = slower changes.

Time to Peak (Tmax)

6 h

Roughly when you feel the main effect after a dose.

What it hits (receptors)

Primary:

SERT (inhibitor)NET (inhibitor (dose-dependent))

Low dose = mostly serotonergic; >150 mg = significant NE effects.

How your body processes it (metabolism)

Substrate: CYP2D6Secondary: CYP3A4

Converted to active metabolite O-desmethylvenlafaxine (desvenlafaxine).

⚠️ Warnings

SNRI with infamous withdrawal (“brain zaps,” dizziness, agitation).
Can cause significant sweating and raised blood pressure.
Strong emotional blunting reported.
Often described as harder to quit than SSRIs.
Common side effects: nausea, sexual dysfunction, insomnia.

⏬ Taper & Withdrawal

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If you’re reducing

Requires very gradual taper. Known for severe discontinuation syndrome.

Possible withdrawal

“Brain zaps”, dizziness, nausea, agitation, vivid dreams — can be severe even if one dose missed.

Info here is educational, not medical advice. Always taper with prescriber support if possible.

🧠 Trusted External Sources Last reviewed 22 Aug 2025, 21:27 by Connor O’Driscoll

Drugs.com

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NHS

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🔗 Interaction Checker

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⚠️ Black Box Warning

All antidepressants: ↑ suicidal thoughts/behaviours in under-25s.

This is a plain‑English summary of headline safety warnings. Talk to a clinician before changing any medication.

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