Serotonin-norepinephrine reuptake inhibitors
Blocking reuptake of both serotonin and norepinephrine.
Also called SNRIs and serotonin-noradrenaline reuptake inhibitors.
Class card
- Drugs
- Venlafaxine and Duloxetine
- Used for
- Depression
- Generalized and social anxiety disorder
- Panic disorder
- Diabetic nerve pain
- Known for
- Raised blood pressure
- Discontinuation symptoms if stopped suddenly
- Name stems
- -oxetine
3 cards: the class, and each drug in it.
Mechanism of action
How do serotonin-norepinephrine reuptake inhibitors work?
SNRIs block both the serotonin transporter (SERT) and the norepinephrine transporter (NET), so both transmitters stay longer in the synapse. The added norepinephrine effect is thought to help with nerve pain, and it can also push blood pressure up. Like SSRIs, they have no significant affinity for muscarinic, histamine or α1 receptors, so they lack the sedating and anticholinergic burden of tricyclics.
The drugs
Serotonin-norepinephrine reuptake inhibitors with a card
- VenlafaxineIts blood pressure rise is dose-related, and its active metabolite desvenlafaxine shares its effects; people allergic to desvenlafaxine should not take it.
- DuloxetineBesides depression and anxiety, it is licensed for three pain conditions: diabetic peripheral nerve pain, fibromyalgia and chronic musculoskeletal pain.
Uses
What are serotonin-norepinephrine reuptake inhibitors used for?
- Depression
- Generalized and social anxiety disorder
- Panic disorder
- Diabetic nerve pain
- Fibromyalgia
Side effects
Side effects of serotonin-norepinephrine reuptake inhibitors
- Raised blood pressureKnown forSerious
- Discontinuation symptoms if stopped suddenlyKnown for
- Nausea
- Dry mouth
- Heavy sweating
- Sexual problems, such as abnormal ejaculation
- Serotonin syndromeSerious
- Suicidal thoughts in children and young adultsSerious
- Low sodium (hyponatremia)Serious
- Abnormal bleedingSerious
What the class has in common. Each drug's card has its own, and Known for marks what an exam expects you to know.
Watch for
Cautions
- Check blood pressure before starting and regularly during treatment; bring high blood pressure under control first.
- Never combine with an MAOI: wait 14 days after an MAOI, and 7 days (venlafaxine) or 5 days (duloxetine) before one.
- Taper the dose gradually when stopping, to limit discontinuation symptoms.
- Monitor people under 25 closely for worsening mood or suicidal thinking, especially early in treatment.
Remember them
A way to remember them
The extra N brings nerve-pain relief and a blood pressure check.
Blocking norepinephrine reuptake as well as serotonin is why duloxetine treats diabetic nerve pain and fibromyalgia, and why SNRIs can raise blood pressure, which is measured before and during treatment.
Written for biofideX
Name stems
-oxetine means selective reuptake inhibitor (fluoxetine type)
Fluoxetine is an SSRI, duloxetine an SNRI, and atomoxetine, used for ADHD, blocks norepinephrine reuptake alone. Sertraline and citalopram are SSRIs that lack the stem.
- Every drug name stem
Don't mix them up
Classes easily confused with these
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Antidepressants (NHS)
- Venlafaxine hydrochloride extended-release capsules: label (DailyMed)
- Duloxetine delayed-release capsules: label (DailyMed)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Depression, anxiety and sleep
Practice serotonin-norepinephrine reuptake inhibitors with the other classes in this group: what each drug is, how it works, what it treats and what it's known for.
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