Effexor is a drug used to treat major depressive disorder, generalized anxiety disorder, and panic disorder. It works by inhibiting the reuptake of serotonin and norepinephrine in the brain. Common side effects include nausea, insomnia, dizziness and headache. Nurses monitor patients taking Effexor for changes in mood, suicidal ideation, blood pressure and weight. They educate patients about taking the drug as prescribed, possible side effects and drug interactions.

1. Running head: EFFEXOR 1
Effexor
Lisa Burks
Hardin-Simmons University
Pharmacology
NURS 3423
Chaluza Kapaale, MSN, RN
December 6, 2013

2. EFFEXOR 2
Effexor
Venlafaxine, commonly known by the brand name Effexor, is a drug used to treat
disorders such as major depressive disorder, generalized anxiety disorder, and panic disorder
with or without agoraphobia (“Venlafaxine,” 2012). Depression is thought to be caused by a
deficiency in the production of the neurotransmitter serotonin, lack of serotonin receptor sites, or
the inability for serotonin to reach the receptor sites (Bouchez, 2011). Serotonin is believed to be
the neurotransmitter responsible for mood regulation. The drug falls under the classification
Serotonin norepinephrine reuptake inhibitor (SNRI), which means that it prevents the
neurotransmitters serotonin and norepinephrine from being reabsorbed in the brain. This leaves
both the serotonin and the norepinephrine in the synapse where they can continue to trigger the
receptors. SNRIs are different than selective serotonin reuptake inhibitors (SSRIs) because they
block both serotonin and norepinephrine, instead of just serotonin. Both classifications of drugs
are used to treat depression, but due to the different chemical structures, the drugs will affect
individuals differently.
Effexor was approved by the Food and Drug Administration in 2005 initially as a drug to
treat panic disorder (“Effexor,” 2005). To understand Effexor completely, it is imperative to
venture through the pharmacodynamics, pharmacokinetics, possible side effects, and the nursing
implications. Through these aspects, nurses will learn about this multi-faceted drug and how it
influences and changes the body.
Pharmacodynamics
The pharmacodynamics of Effexor focus on how the drug acts on the central nervous
system. The drug potentiates neurotransmitter activity in the brain. Venlafaxine’s active
metabolite, O-desmethylvenlafaxine (ODV), is a potent inhibitor of serotonin and

3. EFFEXOR 3
norepinephrine reuptake (“Effexor,” 2006). Pharmacologic activity is believed to “be associated
with the various anticholinergics, sedative, and cardiovascular effects seen with other
psychotropic drugs” (“Effexor,” 2006). Psychotropic drugs are a classification of drugs that can
cross the blood-brain barrier and act on the central nervous system. Venlafaxine and its
metabolite, ODV, “have no significant affinity on the muscarinic, histaminergic, or alpha-1
adrenergic receptors in vitro” and do not contain “any monoamine oxidase (MAO) inhibitory
activity” (2006).
Pharmacokinetics
Effexor is a drug that is given orally and is offered in two different types: Effexor
or Effexor XR. Ogbru and Conrad Stoppler (2010) stated the following about Effexor: Effexor,
which is immediately released, is usually given at a dose of 75 mg/day, divided into two or three
doses per day. If the patient has created a tolerance to the drug, their dosage may be increased to
150 mg/day, and then to 225 mg/day, which is usually the maximum. For those patients whom
are more severely depressed, then 350 mg/day was found to help with the depression. All
dosages are still given in two to three divided doses. Dr. Davis (2010) stated these implications
for Effexor XR. Effexor XR is given in an extended time released capsule. The dose starts at 75
mg/day, taken once a day. The time of day is recommended to be either in the morning or
evening. It needs to be taken with food. These capsules should not be divided, crushed, chewed,
or placed in water. New patients may be started out at 37.5 mg/day for 4-7 days to allow their
bodies to adjust to the new medication (Davis, 2010). After the 4-7 days, these patients’ dose
may be increased to 75 mg/day.
Absorption of the drug is 92-100% after oral administration (Hazard Vallerand,
Sanoski, & Hopfer Deglin, 2013). Effexor has extensive distribution into the body tissues

4. EFFEXOR 4
(Hazard Vallerand et al., 2013). With a first pass though the liver, the drug is extensively
metabolized. Venlafaxine’s active metabolite, ODV, fulfills the purpose of the drug because it
carries out the antidepressant activity. About 5% of venlafaxine is excreted in the urine; 30% of
ODV is excreted in the urine (Hazard Vallerand et al., 2013). The half-life for venlafaxine is
three to five hours, nine to eleven hours for ODV; both of these are increased with hepatic or
renal impairment (Hazard Vallerand et al., 2013). Considering the half-life for ODV, this
explains why the drug must be taken once a day. Perhaps due to tolerance, when the drug is
taken in two or three divided doses, like with Effexor, the doses will begin to build on one
another for the desired therapeutic effect. Specifically with the antidepressant action, it takes
about 2 weeks for the onset to occur with a peak of 2-4 weeks (Hazard Vallerand et al., 2013).
This happens after the doses have started to build on one another to produce the desired effect.
The duration of this drug is unknown.
Adverse Reactions
Effexor affects many areas of the body. Explicitly in the central nervous system, effects
known to happen are abnormal dreams, anxiety, dizziness, headache, insomnia, nervousness, and
weakness (Hazard Vallerand et al., 2013). Distinct effects that warrant one to notify their
healthcare provider are: neuroleptic malignant syndrome, seizures, and suicidal thoughts (Hazard
Vallerand et al., 2013). All of the above could be life-threatening. Neuroleptic malignant
syndrome is a rare but serious side effect that is caused by antipsychotic drugs. The signs of this
are high fever, muscle rigidity, altered mental status (paranoid behavior), and autonomic
dysfunction (“Neuroleptic malignant syndrome,” 2012). Autonomic dysfunction means defective
functioning of the autonomic nervous system that results in wide swings of blood pressure,
diaphoresis, and excessive secretion of saliva (“Neuroleptic malignant syndrome,” 2012).

5. EFFEXOR 5
Effexor is a drug that affects the neurotransmitter levels in the brain, a part of the CNS, so it is no
surprise that these kinds of side effects occur. However there are other side effects that happen
frequently, in different areas of the body. For example, in the ear, nose, and throat region, rhinitis
and visual disturbances are common to occur (Hazard Vallerand et al., 2013). When taking any
medications, rarely is the GI system not influenced-there is no change here, as there are many
side effects that can be explained to be a result of Effexor. These include: abdominal pain,
altered taste, anorexia, constipation, diarrhea, dry mouth, dyspepsia, nausea, vomiting, and
weight loss (Hazard Vallerand et al., 2013). Side effects in other areas of the body are sexual
dysfunction, ecchymoses, paresthesia, and chills (Hazard Vallerand et al., 2013). Serotonin
syndrome is another potentially life-threatening side effect. This happens when you are taking
medications that increase the level of serotonin in your body, such as the intended effect of
Effexor (“Serotonin syndrome,” 2011). Symptoms of this are confusion, restlessness, high blood
pressure, twitching muscles, diaphoresis, headache, and shivering. Severe symptoms include a
high fever, seizures, irregular heartbeat, and unconsciousness (“Serotonin syndrome,” 2011).
Serotonin syndrome may also be instigated when concurrent use of drugs that affect serotonergic
neurotransmitter systems, such as linezolid, tramadol, and triptans (Hazard Vallerand et al.,
2013). There is a certain level at which the brain can work with serotonin levels. When a patient
is taking multiple drugs that affect the serotonin pathway, there can be adverse reactions to this
phenomenon that suggest too high dosage of drug(s). If a patient is taking MAO inhibitors,
concurrent use with Effexor may cause serious, potentially fatal reactions (Hazard Vallerand et
al., 2013). Hazard Vallerand et al. state having stopped taking MAO inhibitors at least 2 weeks
prior to beginning Effexor therapy. It is important to know the possible adverse reactions to any
drug before taking it, however weighing the potential benefits against the negative effects should

6. EFFEXOR 6
occur. It is hard to know how each patient will react to a drug. The desired effect is increasing
serotonin levels in the brain, which then will help relieve a patient’s depression and stabilize
their moods. If this outcome seems worth the potential risks and the patient isn’t taking any other
medications that are contraindicated with Effexor, then taking this drug could possibly help the
patient. That is the primary goal of care: to help the patient.
Nursing Implications
Prior to and during drug therapy, nurses assess their patients. Things to look for in
assessment include any changes from the previous assessment and how well the drug is working.
A thing to assess a patient for that is taking Effexor is their mental status and mood changes.
Specifically you’re looking for any “significant increase in anxiety, nervousness, or insomnia”
(Hazard Vallerand et al., 2013). Along with these mood changes, assess for any suicidal ideation,
which can include the patient talking about death a lot, wondering what would happen if they
were to die, and picturing ways they could die. Sometimes, the patient doesn’t present with the
symptoms of simply saying, “I want to kill myself.” Suicidal ideation is more common in early
therapy on Effexor and in children, adolescents, and adults younger than 24 years old have an
increased risk for this side effect (Hazard Vallerand et al., 2013). Sustained hypertension may
occur, so monitoring blood pressure periodically is necessary (Hazard Vallerand et al., 2013).
This could be as a result from too high of a dose of Effexor. Also, monitor appetite and
nutritional intake and have the patient weigh weekly and report continued weight loss (Hazard
Vallerand et al., 2013). Weight loss is a common side effect of Effexor; however the patient
should still not follow below minimum BMI requirements. Finally, assess for serotonin
syndrome, which may include symptoms such as agitation, hallucinations, autonomic instability
(tachycardia, hyperthermia), neuromuscular aberrations (hyper-reflexia, incoordination), and/or

7. EFFEXOR 7
GI symptoms (Hazard Vallerand et al., 2013). Venlafaxine inhibits serotonin reuptake, which
leaves the drug in the synapse for longer periods of time. Any alteration in a hormone requires
monitoring of any sudden changes, because that means the drug may not be the right dose for
this patient’s body make-up. This explains why every patient can simply not be on the same dose
throughout. Each patient is made differently, and the variance between each patient’s dose
reflects this.
Specific client teaching includes taking as directed at the same time each day. When
taking PO, venlafaxine should be taken with food, so the patient can take it with breakfast every
day at the same time (Hazard Vallerand et al., 2013). If a dose was missed, take it as soon as
possible. Do not double up on doses or stop taking abruptly. Advise the patient and family to
look for any suicidality, new or worsening depression or anxiety, agitation, panic attacks,
insomnia, new or worsening irritability, or mania and to notify health care provider (HCP) if any
of this occurs (Hazard Vallerand et al., 2013). When these symptoms occur, early detection is
best because the effects can be less detrimental to the patient. Advise the patient to avoid driving
because Effexor may cause drowsiness (Hazard Vallerand et al., 2013). Notify HCP of any other
prescription drugs or over the counter medication, vitamins, or herbs because these could cause
drug interactions. Avoid alcohol during therapy. Notify HCP is rash occurs as this may be signs
of an allergy. In female patients, inform HCP if pregnancy is planned or suspected, or if
currently breastfeeding. Effexor is pregnancy category C, meaning that in animal studies it has
shown adverse effects to the fetus however no human studies have been conducted. Lastly,
emphasize the need for follow-up exams to monitor progress (Hazard Vallerand et al., 2013).
With Effexor, it affects many areas of the body because it affects serotonin and norepinephrine.
These hormones affect the body as a whole. Frequent assessments of the patient’s condition

8. EFFEXOR 8
while on this drug are required to note any tolerance to the dose, adverse effects, or the success
of therapy. Therapy is usually continued for several months, which is a big time frame that must
be properly assessed and re-evaluated frequently.
Conclusion
Once doses have begun to build upon one another, the therapeutic effects of Effexor will
start presenting themselves. This takes about 2 weeks to happen. After this point, the peak is
about 2-4 weeks. It is important for a patient to continue taking Effexor as prescribed, even if
depression symptoms have gone away. If the patient were to stop taking it, the depression
symptoms would return once enough of the drug was to wear off and fall below the threshold
level, which depends on the individual. With a medication like Effexor, since it is dealing with
neurotransmitters and the way the brain responds to them, the probability of having side effects
becomes much higher. With that being said, the benefits to a patient that is in need of this drug
can outweigh the negative consequences. Effexor works to stabilize moods and help calm an
individual who may be suffering from panic attacks. The nursing implications become very
important with this drug. The nurse should watch for any serious side effects, primarily having
suicidal thoughts. Different assessments could include assessing for suicidal thoughts or mood
swings. Nursing assessment with this drug create the need for multiple, frequent visits in order to
be assessed and to determine the drug’s effectiveness.

9. EFFEXOR 9
References
Bouchez, C. (2011, October 12). Serotonin: 9 questions and answers. Retrieved from
http://www.webmd.com/depression/features/serotonin
Davis, C. P. (2010, December 15). Effexor xr. Retrieved from http://www.rxlist.com/effexor-xr-
drug/indications-dosage.htm
Effexor XR. (2005). Formulary, 40(12), 425-426.
Hazard Vallerand, A., Sanoski, C., & Hopfer Deglin, J. (2013). Davis's drug guide for nurses. In
J. Rodenberger (Ed.), Venlafaxine (13 ed., pp. 1273-1275). Philadelphia, PA: F. A. Davis
Company.
Neuroleptic malignant syndrome. (2012, May 16). Retrieved from
http://www.webmd.com/schizophrenia/neuroleptic-malignant-syndrome
Ogbru, O., & Conrad Stoppler, M. (2010, December 15).Effexor. Retrieved from
http://www.rxlist.com/effexor-drug/indications-dosage.htm
Serotonin syndrome. (2011, February 8). Retrieved from
http://www.mayoclinic.com/health/serotonin-syndrome/DS00860
U.S. Food and Drug Administration, (2006). Effexor. Retrieved from Wyeth Pharmaceuticals,
Inc. website:
http://www.accessdata.fda.gov/drugsatfda_docs/label/2006/020151s044,020699s071lbl.p
df
Venlafaxine extended release (generic): EFFEXOR XR (BRAND). (2012). Brown University
Psychopharmacology Update, 231-2.