Antidepressants: The Need-to-Know Series (Part 3: The SSRIs, SNRIs, NDRI)

by | Feb 4, 2011

Your neighbor can’t stop talking about the wonders of Lexapro. He suggests you talk to your doc about an SSRI for your depression and anxiety. You reply, “What’s an SSRI?” Hey, if you don’t know, you have to ask. Let’s get you an answer… 

Alcohol, drug, and supplement interaction is always a concern. Chat with your physician regarding the meds or supplements you’re taking or considering.

In part one of our series, we reviewed some history, the tricyclic antidepressants (TCAs), and the tetracyclic antidepressants (TeCAs). We covered the monoamine oxidase inhibitors (MAOIs) in part two.

In this installment, we’re going to explore the selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), and a norepinephrine dopamine reuptake inhibitor (NDRI).

Selective serotonin reuptake inhibitors (SSRIs)

The first SSRI was fluoxetine (Prozac), introduced in 1988. The SSRIs indicated for treatment of the mood and anxiety disorders are citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac), fluvoxamine (Luvox), paroxetine (Paxil), and sertraline (Zoloft).

How do SSRIs work?

Serotonin is a neurotransmitter believed to be involved in the generation of mood and anxiety issues. In part one, we discussed the dynamics of reuptake. The SSRIs inhibit the reuptake of serotonin, allowing more to stick around as neurons communicate.

Why would I take an SSRI?

The SSRIs are prescribed for the treatment of depression, anxiety disorders, eating disorders, chronic pain, irritable bowel syndrome, premature ejaculation, and more.

Any side effects?

SSRI side effects include dry mouth, constipation, nausea, fatigue, urinary retention, appetite/weight changes, tremor, difficulty achieving orgasm, erectile dysfunction, and decreased libido.

Serotonin norepinephrine reuptake inhibitors (SNRIs)

The first SNRI, venlafaxine (Effexor), was introduced in 1994. The SNRIs indicated for the treatment of the mood and anxiety disorders are venlafaxine (Effexor), desvenlafaxine (Pristiq), duloxetine (Cymbalta), milnacipran (Savella), and levomilnacipran (Fetzima).

How do SNRIs work?

Refer to the “How do’s” of the SSRIs and add the neurotransmitter norepinephrine.

Why would I take an SNRI?

First and foremost, SNRIs are prescribed for depression. They’re also used for the treatment of the anxiety disorders, neuropathic pain, fibromyalgia, and the relief of menopausal symptoms.

Any side effects?

Refer to the side effects for the SSRIs. However, some reports suggest SNRI side effects may not be as severe. And with regard to sexual side effects, though the SNRIs have the same profile as the SSRIs, an increase in libido has been reported.

Other concerns?

High blood pressure needs to be managed and monitored. Duloxetine (Cymbalta) has been associated with liver failure, so it’s not an option for chronic alcohol users or those with liver disease.

Norepinephrine dopamine reuptake inhibitor (NDRI)

Bupropion (Wellbutrin, Zyban, Budeprion) was first approved for medical use in the U.S. in 1985. On its own it’s an effective antidepressant. But it’s frequently used as an add-on when the SSRIs aren’t working as expected. It’s also used as a smoking cessation aid. Of note, bupropion doesn’t usually cause weight gain, sexual dysfunction, or sleepiness

How does bupropion (Wellbutrin, Zyban, Budeprion) work?

Bupropion, considered an atypical antidepressant, acts as a norepinephrine dopamine reuptake inhibitor. What makes it unique is its dance with the neurotransmitter dopamine. It’s twice that of its action with norepinephrine. Its success as a smoking cessation aid is due to its effect on acetylcholine (a neurotransmitter) receptors.

Why would I take it?

Bupropion is used to treat depression, the symptoms of smoking cessation, social phobia (aka social anxiety), anxiety co-existing with depression, sexual dysfunction, obesity, adult ADHD, and neuropathic pain. It may also be useful in the treatment of Crohn’s Disease and psoriasis.

The fact that bupropion doesn’t usually cause weight gain, sexual dysfunction, or sleepiness makes it the preferred antidepressant for many.

Any side effects?

Common side effects include agitation, anxiety, buzzing in the ears, skin rash, hives, itching, and headache.

Bupropion lowers seizure threshold, but at recommended doses it shouldn’t present problems. Hypertension, resulting in headaches, blurred vision, and other symptoms could be an issue. Blood pressure monitoring may be suggested.

Other concerns?

Bupropion may cause anaphylaxis, which can be life-threatening. So, if you’re experiencing itching, a rash, swelling of the face, tongue, and throat; breathing difficulty, or chest pain – seek immediate medical attention.

The FDA has ordered that all antidepressants carry a Black Box Warning indicating that they are associated with an increased risk of suicidal thinking, feeling, and behavior in children and adolescents. A warning is also given for an increased risk of suicidal symptoms in young adults, ages 18-24.

Alcohol, drug, and supplement interaction is always a concern with antidepressants. Chat with your physician regarding the meds or supplements you’re taking or considering, as well as your alcohol intake

The sudden cessation of any antidepressant is a bad idea. You won’t like the outcome.

That’ll do it

Well, that’ll do it for today’s discussion. Be sure to dig-in to part four – the final piece of the series. It’s a summary, which will include my personal thoughts on antidepressants.

You may find the FDAs Information for Consumers and Patients website helpful. And you may just find the hundreds of Chipur articles helpful as well. You won’t know unless you check ’em out.

Bill White is not a physician and is providing the contents of this article for information purposes only, not to serve as a recommendation. Contact your physician with questions and for advice. 

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