Psychiatry/SNRI

SNRIs

also: venlafaxine · duloxetine

Overview

Serotonin–noradrenaline reuptake inhibitors — second-line for depression and useful in neuropathic pain (duloxetine).

Mechanism

Block reuptake of both serotonin AND noradrenaline → ↑both monoamines. The noradrenergic action helps pain and energy but raises blood pressure at higher doses.

Indications

Depression (when SSRI ineffective)
Generalised anxiety
Diabetic neuropathy / neuropathic pain (duloxetine)

The agents

Venlafaxinedepression/GAD

Dose-related hypertension; dangerous in overdose (more than SSRIs); marked discontinuation.

Duloxetinedepression + pain

First-line for diabetic neuropathy (cross-ref Neuropathic pain).

Adverse effects

Hypertension (dose-related)serious

Monitor BP.

Nausea, dry mouth, sweatingcommon

Discontinuation syndromecommon

As SSRIs: suicidality early, hyponatraemia, bleedingcommon

Cautions & contraindications

Uncontrolled hypertensionall

Within 2 weeks of an MAOIall

Serotonin syndrome.

Interactions

Serotonergics → serotonin syndrome; other antihypertensive considerations

Monitoring & kinetics

BP; response; Na⁺

Oral; taper to stop (venlafaxine discontinuation is marked).

Source: NICE NG222 — Depression · BNF — SNRIs