Serotonin Norepinephrine Reuptake Inhibitors (SNRI)
Mechanism: increases serotonin and norepinephrine levels in the brain. The SNRI’s are used for depression and pain management.
SNRI Side Effects:
- Side effects: very favorable profile: minimal drowsiness and cardiovascular effects.
- Common side effects: nausea, loss of appetite, insomnia, nervousness, restlessness, and grinding of teeth. All these side effects increase as dose is increased.
Venlafaxine (Effexor®) – FDA approved 1993
- Also approved for Generalized Anxiety Disorder and Seasonal Affective Disorder
- Unlabeled use: hot flashes, Premenstrual Dysphoric Disorder, PTSD
- Caution: angle closure glaucoma or patients taking oral anticoagulants.
Duloxetine (Cymbalta®) – FDA approved 2004
- Very low side effect profile
- May cause decrease in body weight
- Caution: caution in kidney failure
- contraindicated in patients with heavy alcohol use or chronic liver disease; can lead to acute hepatitis
- ***is approved for diabetic neuropathy and fibromyalgia***
Desvenlafaxine (Prestiq®) – FDA approved 2008
- Treatment of adults with major depressive disorder.
- Is the active metabolite of Effexor. It does not require “activation” by the liver enzymes, minimizing the potential for drug interactions.
- There was no evidence that doses greater than 50 mg/day confer any additional benefit.
- Less sexual dysfunction.
- Nausea most frequently during week one.
- May increase blood pressure.
Milnacipran (Savella®) – FDA approved Jan-2009
- Use: selective norepinephrine and serotonin reuptake inhibitor (SNRI) for management of fibromyalgia. First drug approved ONLY for fibromyalgia.
- More potent inhibitor of norepinephrine reuptake than the other SNRIs.
- Norepinephrine depletion is associated with pain and fatigue. 1 in 12 patients get about 50% reductions in fibro symptoms.
- Adverse reactions: nausea, headache, constipation, dizziness, insomnia, hot flush, excess sweating, vomiting, palpations, increased heart rate, dry mouth, and hypertension.
- CAUTION: avoid in kidney failure, chronic liver disease, or alcohol abuse.
Levomilnacipran (Fetzima®) – FDA approved 2013
- Once-daily serotonin and norepinephrine reuptake inhibitor (SNRI) for the treatment of major depressive disorder (MDD) in adults, has received FDA approval
- Stronger inhibitor of norepinephrine than serotonin.
- Dosage: 40 mg to 120 mg once daily, beginning with 20 mg once daily for 2 days and then 40 mg once daily. Dosage can be increased in increments of 40 mg at intervals of 2 or more days, with 120 mg the maximum recommended dose.
- Monitor BP and heart rate for increases.
- CAUTION: kidney failure, angle closure glaucoma, high blood pressure, dose dependent erectile dysfunction.
HYPONATREMIA: older patients are more likely to develop low sodium with an SSRI or SNRI or mirtazapine than younger counterparts. Be sure to monitor sodium especially in patients with heart failure, or those taking hydrochlorothiazide. They made the Beers List for that reason.
Because of the opioid crisis more physicians are turning to this class of drugs to help manage pain. Your Thompson Pharmacist is an excellent resource to help your pain or improve your mood. Except for Fetzima and Savella, all of the other SNRI’s are available as generic drugs. You will save a bundle using our high-quality generic drugs. Go Ahead and ASK… at Thompson Pharmacy it’s ALL for YOU!!!