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medication / antidepressants / Effexor and Pristiq (NaSSRI)

Selective Serotonin and Noradrenaline Reuptake Inhibitors (NaSSRIs): Effexor XR and Pristiq



Mental health problems

  • Depression

  • Anxiety disorders


Physical health issues

  •   Fibromyalgia

  • Premenstrual dysphoria: symptoms resembling premenstrual syndrome usually preceding menstruation, but to a much greater degree (loss of interest in activities of daily living, impaired sleep, feeling of loss  control, lack of energy, physical symptoms, changes in eating habits and trouble concentrating, irritability, depressed mood, emotional lability, anxiety and tension).



Mental health problems

  • Taken together: MAOIs and similar antidepressants

  • History of manic episodes


Physical health issues

  • people with allergies

  • Blood and kidney diseases

  • History of seizures

  • Untreated angle-closure glaucoma



Not indicated for children under 18 years of age

Drugs interactions


Mental health problems

  • Methylphenidate (Ritalin), antihistamines, chloral hydrate and cimetidine (Tagamet) increase the effect of SSRIs

  • Never combine with an MAOI antidepressant and at least 14 days apart from taking an SSRI or an SSRI Na and an MAOI

  • Carbamazepine (Tegretol) and barbiturates reduce the effect of SSRIs

  • Paroxetine (Paxil) and fluoxetine (Prozac) can reduce the effect of tamoxifen (hormone therapy to treat breast cancer)

  • Paroxetine (Paxil) and fluoxetine (Prozac) increase the effects of some antipsychotics  and all tricyclic antidepressants


physical health problem

Ritonavir and fosamprenavir  (antiretroviral drugs that work  preventing the multiplication of HIV) may reduce the effect of paroxetine (Paxil)



Alcohol not recommended

Side effects

They depend on the dosage and duration of treatment, the metabolism of the individual and the context in which he lives.


  • Nausea

  • Vomiting

  • Constipation



Loss of appetite



  •  Vertiges

  • Dry mouth


  • Insomnia

  • Drowsiness



  • Sweat

  • Chills

  • Tremors



Ejaculation, orgasm and impotence problems in men



  • Nervousness, anxiety

  • Mania Activation

  • Increased risk of behavioral changes, suicidal ideation and self-harm



Increased blood pressure and heartbeat



Abnormal bleeding



  • Fatigue

  • Symptoms Related to Sudden Discontinuation of Treatment

Withdrawal symptoms

Psychotropic drugs act in the brain just as they do in the rest of the body; and as we have seen, each person reacts differently. It's the same with weaning; the person's metabolism, the type of drug, the dose as well as the duration of the intake and its half-life, explain that the withdrawal effects are varied. We have listed the potential and main withdrawal symptoms of each class of psychotropic drugs. This list is incomplete, as not all withdrawal effects are listed; moreover, knowledge is rapidly evolving in this field. A person may have no withdrawal symptoms or experience one, a few, or even many. The medication reduction journey is specific to each person, just as each process is unique. For example, a person can take the same medicine twice at the same dose and the effects will be different. Gradual reduction, like removing 10  % of dose per week/month, reduces the frequency or intensity of withdrawal symptoms and the incidence of rapid relapses. It is very important to undertake this process with the collaboration of your doctor. The pharmacist also plays a key role and can provide guidance to monitor withdrawal effects for each medication. Most people who will have withdrawal symptoms will tolerate them without problems for the short duration of these symptoms.


Common and frequent withdrawal symptoms for all classes: anxiety, nervousness, restlessness, sleep problems, greater need to rest, sleep, irritability, fatigue.

Withdrawal symptoms usually appear one to seven days after a discontinuation or a significant reduction in dose. About 55% of people feel as if they are going through a period of excitement or depression which is accompanied by raw emotions, anxiety, disturbing dreams and lethargy (numbness of being) temporary. These effects disappear within a few days.


Withdrawal symptoms for NaSRI antidepressants:

Selective serotonin reuptake inhibitors or SSRIs (Prozac, Luvox, Zoloft, Paxil and Celexa), serotonin and norepinephrine reuptake inhibitors or SNRIs (Effexor, Cymbalta and Pristiq) and bupropion share these symptoms of weaning.


Main psychological withdrawal symptoms:

  • Anxiety

  • Irritability

  • Hustle

  • Insomnia

  • Nightmares or dreams of intense realism (vivid)


Very rarely:

  • Suicidal tendencies or tendencies to want to harm themselves which can appear suddenly at the time of increases or reductions. These symptoms are  often preceded by a period of severe agitation (akathisia).

  • Mania or hypomania


Main physical withdrawal symptoms:

(= flu-like effects)

  • Headaches (headaches)

  • sweating

  • Fatigue

  • General malaise

  • Muscle aches

  • Diarrhea

  • Dizziness, vertigo

  • Tremors

  • Numbness or tingling of the extremities

  • Electric shock sensations in the limbs

  • Blurry vision

  • Very rarely:

  • Concentration or memory problems

  • Movement disorders


Effexor and Paxil have shorter durations of action than other antidepressants. They can give withdrawal reactions that are more difficult to control from day one. It is therefore even more important to gradually reduce the dose.

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