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Effexor Side Effects

The anti-depressant drug Effexor has been linked to several serious side effects and complications in patients taking the medication. Some of these side effects can cause lasting harm to fetuses of pregnant patients. Many side effects can be deadly.

The antidepressant and anti-anxiety drug Effexor (venlafaxine) has been linked to serious side effects and complications that can be deadly to patients and fetuses. One such birth defect associated with Effexor use in pregnancy is a serious and potentially fatal condition affecting the heart and lungs of newborns.

Effexor Warning
Pregnant women taking Effexor are at an increased risk of miscarriage.

Effexor and Effexor XR (the extended-release version of the drug) work to boost serotonin and norepinephrine levels in the brain by blocking the neurotransmitters’ reabsorption, thereby attempting to increase positive feelings along with alertness and energy. But Effexor can worsen depression and lead to a heightened risk of suicidal thoughts and behaviors.

Effexor, a serotonin-norepinephrine reuptake inhibitor (SNRI), is also linked to the following serious side effects:
  • Serotonin syndrome
  • Elevations in blood pressure
  • Weight and height changes in pediatric patients
  • Appetite changes in pediatric patients (treatment-emergent anorexia)
  • Interstitial lung disease and eosinophilic pneumonia
  • Discontinuation syndrome

Miscarriage in Pregnant Women Taking Effexor

The use of antidepressants has been linked to an increased risk of miscarriage, according to a study published in the Canadian Medical Association Journal (CMAJ) in 2010.

University of Montreal and the CHU Sainte-Justine Mother and Child University Hospital researchers reviewed data collected by the Quebec Pregnancy Registry from 1998 to 2003. The review covered information about 70,000 women between the ages of 15 to 45.

Women taking Effexor during pregnancy have a nearly 70 percent increased risk of miscarriage.

The evaluation included over 5,000 women who had experienced miscarriages up to 20 weeks into the pregnancy and another 51,000 women who did not have miscarriages. Of those women who miscarried, about 5.5 percent (or 284) had taken antidepressants during their pregnancy.

Overall, the study found a 68 percent increased risk of miscarriage in women who used antidepressants, such as Effexor, during pregnancy compared to those women who never used antidepressants.

What Is a Miscarriage?

A miscarriage is the unexpected loss of a fetus occurring before the 20th week of pregnancy, or gestation. If the loss of a fetus occurs after the 20th week, it is referred to as a stillbirth rather than a miscarriage. The majority of miscarriages happen very early in a pregnancy, sometimes before a woman even knows she is pregnant.

Factors that might contribute to a miscarriage include:
  • A genetic (chromosomal) problem with the fetus that makes it impossible for the baby to develop properly
  • Problems with the uterus (the womb) or the cervix (the lower part of the uterus)
  • Chronic diseases, such as polycystic ovary syndrome (a condition in which a woman’s levels of sex hormones — estrogen and progesterone — are unbalanced, causing the growth of ovarian cysts)

The risk of miscarriage is also higher in women who are older, typically over 30, even greater for those between 35 and 40 years of age, and highest after 40 and in women who have previously had a pregnancy that ended in miscarriage.

Signs and Symptoms of Miscarriage

Vaginal spotting or bleeding may be a symptom of miscarriage or a sign that a miscarriage will occur. However, some women have bleeding in early pregnancy and don’t miscarry. Any bleeding that occurs during a pregnancy should be evaluated by a health care professional.

effexor cramp
Other possible signs and symptoms of miscarriage may include:
  • Low back pain or abdominal pain that is dull, sharp or cramping
  • Tissue or clot-like material that passes from the vagina
  • Vaginal bleeding, with or without abdominal cramps

Treatment of Miscarriage

When a miscarriage happens early in a pregnancy, treatment is not typically needed.

Miscarriage Risk
Surgery may be needed following a miscarriage to prevent infections and other serious health complications

If tissue remains in the uterus, a procedure called a dilatation and curettage (D&C) may be required to remove it and prevent serious infection and further, possibly life-threatening, complications. This surgical procedure involves dilating the opening to the uterus (the cervix) and inserting a small suction tube that scrapes the lining of the uterine walls and empties any pregnancy-related contents.

Persistent Pulmonary Hypertension of the Newborn (PPHN)

The FDA warned consumers about the link between the use of selective serotonin-reuptake inhibitor (SSRI) antidepressants during pregnancy and persistent pulmonary hypertension of the newborn (PPHN). PPHN is a serious, sometimes fatal, condition affecting an infant’s heart and lungs.

The FDA’s warning came in late 2011, over five years after the publication of one case-controlled study in The New England Journal of Medicine (NEJM) that determined a risk of PPHN in infants whose mothers used SSRIs during pregnancy, especially during the third trimester.

Clinical studies have shown that SSRIs and SNRIs, when used during pregnancy, particularly late pregnancy, can cause birth defects and other complications, including:
  • Difficulty breathing
  • Seizures
  • Lack of oxygen in the brain
  • Feeding difficulties
  • Tremors
  • Irritability
  • Constant crying (inconsolable)

Women who take an SNRI, such as Effexor, after the 20th week of pregnancy have also been found to have a six-fold increased risk of having a baby with PPHN.

PPHN damages a newborn’s heart and lungs, making it difficult for the baby to adapt to the environment outside the womb. The condition is rarely detected in utero, and in about 10 to 20 percent of cases, the infant will not survive.

What Is PPHN?

Persistent pulmonary hypertension of the newborn is a severe pulmonary disorder that affects approximately one in every 500 live births. The condition is characterized by the failure of the normal circulatory transition that happens after birth, resulting in shunting (diversion) of blood away from the lungs.

While it is possible for some infants with PPHN to die from the disorder, seven to 20 percent of those who survive will develop long-term complications of the disorder.

PPHN complications might include:
  • Hearing deficit
  • Chronic lung disease
  • Intracranial (within the skull and in the brain tissue) bleed

Pulmonary hypertension is high blood pressure in the arteries of the lungs. It also affects the right side of the heart, causing it to work harder than normal to pump oxygen-rich blood throughout the body.

Unlike adults with pulmonary hypertension, a diagnosis of PPHN is confirmed in newborns regardless of the pressure on the pulmonary arteries, as long as the condition is accompanied by right-to-left shunting without the presence of congenital heart disease.

Blood is pumped through the lungs by the right side of the heart where it collects oxygen. The oxygen-saturated blood then returns to the left side of the heart, where it is pumped to the rest of the body. When the small arteries in the lung narrow, they are unable to carry enough blood. Pressure then builds up, resulting in pulmonary hypertension.

This results in the heart over-working itself to force the blood through the vessels fighting against the building pressure. Over time, this extra work causes the heart to enlarge, resulting in right-sided heart failure.

PPHN Complications
PPHN can result in lifelong health complications in infants who survive with the disorder.

In PPHN, hypoxemia, or an abnormally low level of oxygen in the blood, is a secondary condition.

Signs and Symptoms of PPHN

Frequently changing oxygen levels are often a part of persistent pulmonary hypertension of the newborn. Abnormally rapid breathing (tachypnea) can lead to a severe state of oxygen deprivation in the body (asphyxia). This serious symptom of PPHN can result in the loss of consciousness or death.

Other signs and symptoms of PPHN include:
  • Harsh systolic heart murmur (an unusual sound heard between heartbeats) secondary to tricuspid regurgitation (or the failure of the heart’s tricuspid valve to close properly between heartbeats, or during what’s called systole) or loud, single second heart sound (S2)
  • Low Apgar score (assessment of overall newborn health)
  • Meconium staining (when meconium — an infant’s earliest stool — passes during or before labor there is a greenish or yellowish “stain” that can result on the infant’s skin, umbilical cord or nailbeds)
  • Increased abdomen size
  • Blue or purple color of the lips or skin due to a lack of oxygen in the blood (cyanosis)
  • Poor cardiac function and blood supply through the circulatory system to the organs and tissues
  • Low blood pressure in the arteries of the systemic circulation (systemic hypotension) – blood pressure is the force of blood pushing against the artery walls as blood pumps out of the heart
  • Symptoms of shock, such as low blood pressure, rapid heart rate, poor end-organ circulation (perfusion) and weak pulse

Treatment of PPHN

There is no cure for pulmonary hypertension, and likewise, persistent pulmonary hypertension of the newborn (PPHN).

The primary goal of treatment is to control the patient’s symptoms and prevent any more lung damage from occurring. This can be done by maintaining adequate systemic blood pressure, thereby decreasing pulmonary (affecting the lungs) resistance and ensuring that oxygen reaches the body’s tissues.

Some measures that can be taken to manage PPHN include:
  • Routine monitoring of oxygenation levels, blood pressure and perfusion
  • Maintaining a normal body temperature
  • Correction of electrolytes and glucose abnormalities and metabolic acidosis (when the body produces too much acid or the kidneys are not properly removing enough acid from the body)
  • Proper nutrition
  • Minimal handling and stimulation of the infant
  • Minimal use of invasive procedures
  • Medications to support proper muscle contractions in the heart (such as dopamine)
  • Intubation (placement of a flexible, plastic tube into the windpipe to maintain an open airway) and ventilation (the supply of air to the lungs by artificial means)
  • Induced paralysis for newborns who cannot be treated with sedatives

Effexor’s Other Serious Side Effects and Complications

Effexor’s drug label contains a long list of warnings and precautions linking the antidepressant drug to several other serious side effects and complications.

Like most other antidepressant medications, Effexor has been associated with the worsening of depression and the emergence of suicidal thoughts and/or behaviors, or unusual changes in behavior.

The labeling warns that this “long-standing concern” of antidepressant use leading to an increased risk of suicide in patients, is especially apparent in the “early phases of treatment.” Children, adolescents and young adults who suffer from major depressive disorder (MDD) and other psychiatric disorders, are at an even greater risk of suicide than their counterparts over age 24, and especially those aged 65 and older, who contrarily show a reduction in suicidal risk with the use of antidepressants compared to placebo-controlled groups.

Serotonin Syndrome

The FDA alerted health care professionals to a link between venlafaxine (the active ingredient in Effexor) and a potentially life-threatening condition called serotonin syndrome. The risk of a patient developing this serious and sometime fatal condition is heightened in individuals taking Effexor along with other serotonergic drugs, such as triptans, tricyclic antidepressants, amphetamines and St. John’s Wort, and drugs that impair metabolism of serotonin, such as MAOIs, including those used to treat psychiatric disorders and others.

Symptoms of serotonin syndrome might include:
Mental status changes
agitation, hallucinations, delirium and coma
Autonomic instability
tachycardia, or faster than normal heart rate at rest; labile, or easily changing, blood pressure; hyperthermia, or a dangerously overheated body; sweating; flushing and dizziness
Neuromuscular symptoms
tremor; rigidity; sudden, involuntary muscle jerk, shake or spasm; overactive or overresponsive reflexes; and incoordination
Gastrointestinal symptoms
nausea, vomiting and diarrhea

Elevations in Blood Pressure

Results of controlled trials found dose-related increases in systolic and diastolic blood pressure. These clinical trials also found a link between Effexor use and cases of sustained high blood pressure. Reports have indicated that some cases of elevated blood pressure have required immediate treatment in patients taking Effexor.

Weight and Height Changes in Pediatric Patients

Some children taking Effexor experienced an average change in body weight or incidence of weight loss equal to 3.5 percent or more in placebo-controlled pediatric studies. This weight loss was not limited to patients experiencing anorexia (an eating disorder that results in significant weight loss) as a result of treatment with the antidepressant drug.

The difference between observed weight gain and expected weight gain was larger for children younger than 12 years of age compared with adolescents aged 12 and older.

In a six-month clinical study, both children and adolescents had height increases that were also less than expected when compared with their peers.

Appetite Changes in Pediatric Patients

Decreased appetite, or treatment-emergent anorexia, was observed more frequently in pediatric patients treated with Effexor versus those treated with placebos in a premarketing evaluation.

Interstitial Lung Disease and Eosinophilic Pneumonia

Effexor use has been associated with interstitial lung disease and eosinophilic pneumonia in rare instances, according to drug labeling for the antidepressant medication. Interstitial lung disease is the name for a large group of diseases that can inflame or scar the lungs, resulting in a lack of oxygen. Scarring is permanent.

Eosinophilic pneumonia is a disease in which eosinophils, a type of white blood cell, accumulate in the lungs, and usually in the bloodstream. These cells invade tiny air sacs (alveoli) in the lungs, despite the absence of infection, and make breathing difficult.

lung conditions illustration
Both conditions require treatment, including:
  • Corticosteroids, such as prednisone
  • Medicines used to treat asthma
  • Oxygen therapy
  • Lung transplant (in severe cases)

Discontinuation of Effexor should be considered for patients taking the antidepressant medication when they develop shortness of breath, cough or chest discomfort associated with interstitial lung disease or eosinophilic pneumonia.

Discontinuation Syndrome

Another concern for Effexor patients is discontinuation syndrome, which can occur when the medicine is stopped suddenly, the dose is decreased too quickly or when a dose is missed.

effexor headache
Patients with discontinuation syndrome suffer withdrawal symptoms that can include:
  • Extreme fatigue
  • Severe headaches
  • Stomach cramps
  • Poor coordination
  • Disorientation

To avoid discontinuation syndrome, some doctors switch their patients to SSRIs, which do not have as many withdrawal symptoms, before weaning them off of antidepressants altogether.

Please seek the advice of a medical professional before making health care decisions.

Related Pages

Kristin Compton's background is in legal studies. She worked as a paralegal before joining Drugwatch as a writer and researcher. She was also a member of the National Association of Legal Assistants. A mother and longtime patient, she has firsthand experience of the harmful effects prescription drugs can have on women and their children. Some of her qualifications include:

  • Bachelor of Arts in Legal Studies | Pre-Law from University of West Florida
  • Past employment with The Health Law Firm and Kerrigan, Estess, Rankin, McLeod & Thompson LLC
  • Personal experience battling severe food allergies, asthma and high-risk pregnancies
Edited By
Medically Reviewed By
Dr. Ashrav Ali
Dr. Ashraf Ali Psychiatrist

17 Cited Research Articles

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