Serotonin–norepinephrine reuptake inhibitors (SNRIs)

What they are?

Serotonin–norepinephrine reuptake inhibitors (SNRIs) are a class of antidepressant drugs used in psychiatric treatment. They are primarily used in the treatment of clinical depression, but also in the treatment of anxiety disorders, obsessive-compulsive disorder (OC), attention deficit hyperactivity disorder (ADHD), chronic neuropathic pain, fibromyalgia syndrome (FMS) and other mood disorders. Sometimes serotonin–norepinephrine reuptake inhibitors are even used to relieve menopausal symptoms.

How do they work?

Serotonin–norepinephrine reuptake inhibitors (SNRIs) are different from

other classes of antidepressants because they affect only neurotransmitters serotonin and norepinephrine. Research has shown that the neurotransmitters serotonin and norepinephrine play an important role in the regulation of mood and that mood disorder, such as medical depression or anxiety, can sometimes be explained by abnormal neurotransmitter activity. SNRIs correct imbalances of serotonin and norepinephrine levels.

SNRIs achieve this by blocking the reuptake of serotonin and norepinephrine, this allows more serotonin and norepinephrine to be available in the brain. That is believed to increase the effect of these neurotransmitters. As serotonin can elevate mood and cause a calming effect and norepinephrine can increase alertness, concentration and motivation, SNRIs are believed to relieve clinical depression and other mood disorders.

Do SNRIs have any side effects?

Yes. Side effects of serotonin-norepinephrine reuptake inhibitors (SNRIs) are similar to side effects of selective serotonin reuptake inhibitors (SSRIs) as they have a similar mechanism of action.

Side effects include: drowsiness, headache, nausea, changes in appetite, vivid dreams, sexual dysfunction, dry mouth, anorexia, sweating, insomnia, nervousness, tremor and hypertension.

Are SNRIs addictive?

No but like SSRIs, Serotonin–norepinephrine reuptake inhibitors can also have unpleasant withdrawal symptoms with the most serious symptoms relating to withdrawal syndrome.

Withdrawal symptoms include: dizziness, nausea, vomiting, headache, irritability, unpleasent sensations, such as tingling, burning and shocks, nightmares, tremors, lack of coordination, aggressiveness, suicidal thoughts and balance problems.

What types of Serotonin–norepinephrine reuptake inhibitors are currently availabe?

• Effexor ( Effexor or Efexor) - the first and most commonly used SNRI, works also on dopamine, but mostly effects serotonin and norepinephrine.
• Nefazodone (Serzone, Nefadar) - Serzone is without sexual side effects.
• Duloxetine (Cymbalta, Ariclaim, Xeristar, Yentreve, Duzela)
• Desipramine (Norpramin, Pertofane) - technically a tricyclic antidepressant, but works on both serotonin and norepinephrine, so it can aslo be categorized as an SNRI.
• Milnacipran (Ixel, Savella, Dalcipran, Toledomin)  - is not approved for the clinical treatment of clinical depression in the USA, but is available in Europe and Asia.

Selective serotonin reuptake inhibitors

Selective serotonin reuptake inhibitors (SSRIs) are a class of compounds typically used as antidepressants in the treatment of depression, anxiety disorders, depersonalization disorder and some other personality disorders.

Do they work?

A meta-analysis done in 2010 states that "The magnitude of benefit of antidepressant medication

compared with placebo ... may be minimal or nonexistent, on average, in patients with mild or moderate symptoms. For patients with very severe depression, the benefit of medications over placebo is substantial."

Thus we can draw a conclusion that they do relieve severe depression.

How do they work?

SSRIs are believed to block the reuptake of the neurotransmitter serotonin in the brain. Changing the balance

of serotonin seems to help brain cells send and receive chemical messages, which is believed to boost mood. SSRIs are called selective because they seem to only affect serotonin, not other neurotransmitters.

Do SSRIs have any side effects?

Yes.

Very common - more than 1 person out of 10 may experience these - side effects are the following: nausea, low sex drive and withdrawal effects when stopping taking SSRIs.

Common - 1 person out of 10 may experience these - side effects are the following: blurred vision, dizziness, dry mouth, insomnia or hypersomnia, low appetite, sweating, diarrhoea or obstipation and agitation.

Less common - 1 person out of 100 may experience - are the following: bruising, bleeding, vomiting and vomiting blood, lack of movement, stiffness, abnormal movements of the mouth and tongue, hallucinations, inability to urinate and weight gain.

Rare and very rare side effects are the following: restlessness, convulsions or worsening of epilepsy, elevated mood, anxiety, allergic reaction (breathing difficulties, skin rashes, swelling of the eyelids, face, lips or tongue, itching), serotonin syndrome and glaucoma.

Are they addictive?

No. But SSRIs can have unpleasant withdrawal symptoms (aka discontinuation syndrome) when taking the drugs is stopped suddenly. These are usually avoided or minimised by gradually decreasing the doses of SSRIs over a period of few weeks, before quiting entirely.

What are the withdrawal symptoms?

Dizziness, numbness, nausea, vomiting, headache, sweating, anxiety and sleep disturbances.

Which are the most recommended SSRIs?

The one prescribed by your doctor.

In Unites States, only 5 manufacturers of SSRIs are approved by the U.S. Food and Drug Administration.

Approved are the following: fluvoxamine maleate (Luvox), paroxetine (Paxil), sertraline (Zoloft), citalopram (Celexa) and fluoxetine (Prozac).

Antidepressants

What are antidepressants?

Antidepressants are psychiatric medications used to relieve mood disorders, such as depression, dysthymia and anxiety disorders.

 Do antidepressants work?

Yes and no.

An article published in the Journal of the American Medical Association concluded that antidepressants are no more effective than placebos. In the other hand, there are many psychiatrists who protect the clinical efficacy of antidepressants. For an example, psychiatrist Peter Kramer wrote in his best-selling book Listening to Prozac that this miracle drug made patients "better than well." Data from clinical trials has shown that people treated with placebos improve about 75% as much as patients treated with antidepressants. Therefore, there is proof of efficacy.

How do they work?

There are many different classes of antidepressants. Each of them work on your brain chemistry in a different way. Each increases certain neurotransmitters in the brain and may do this in different parts of the brain.

Different types of antidepressants include:

• Selective serotonin reuptake inhibitors (SSRIs)
• Serotonin-norepinephrine reuptake inhibitors (SNRIs)
• monoamine oxidase inhibitors (MAOIs)
• tricyclic antidepressants
• miscellaneous antidepressants and others.

Are there any side effects of taking antidepressants?

Yes! Different classes have different side-effects. It is very important to let your doctor know or to be reminded of medical conditions you have had in the past or have at the moment.

Are antidepressants addictive?

One-third of people who stop taking SSRIs and SNRIs have withdrawal symptoms. They can last from 2 weeks to 2 months.