, brand name Effexor, belongs to a class of antidepressants
known as serotonin
norephinephrine reuptake inhibitors (SNRIs). It is most commonly prescribed for major depression and/or anxiety disorders.
[top]Introduction to Venlafaxine
Venlafaxine, brand name Effexor, is a phenylethylamine that belongs to a class of antidepressants known as serotonin norephinephrine reuptake inhibitors (SNRIs). It works by blocking the reuptake transporters for norepinephrine and serotonin, allowing the neurotransmitters to remain in the synaptic cleft for an extended period of time and continue to stimulate the post-synaptic neuron. Venlafaxine also appears to weakly inhibit dopamine
reuptake in the frontal cortex of the brain. It is used in the treatment of Major Depressive Disorder, Generalized Anxiety Disorder and Panic Disorder. It should never be taken in combination with other serotogenic or amphetamine
[top]Ways of Administration
Venlafaxine is prescribed for oral administration.
Recommended beginning daily dose of venlafaxine is 75mg, sometimes divided between two to three doses taken throughout the day, depending on your needs. Dosage may be increased in 75mg increments every four days. Extremely depressed patients may take up to 375mg/day in individual doses.
At low doses (<150 mg/day), it acts only on serotonergic transmission. At moderate doses (>150 mg/day), it acts on serotonergic and noradrenergic systems, whereas at high doses (>300 mg/day), it also affects dopaminergic neurotransmission.
[top]Physical effects of Venlafaxine
Venlafaxine is effective at treating the physical symptoms associated with depression, anxiety and panic disorders in some patients. It has also been found to be effective in the treatment of neuropathy and migraines.
Commonly reported physical side effects
of venlafaxine include:
-abnormal ejaculation/orgasm and impotence in men
[top]Psychological effects of Velafaxine
Venlafaxine is effective at relieving the psychological symptoms associated with depression, anxiety and panic disorders in some patients.
Commonly reported adverse psychological side effects of venlafaxine include:
[top]Combinations with Venlafaxine
Venlafaxine should also not be combined with other serotogenic drugs to include MAOIs, SSRIs, SNRIs, psychedelic
, etc.), psychedelic phenylethylamines (MDMA
, etc.), tramadol
, and dextromethorphan
) as it may result in a serious and potential lethal interaction known as serotonin syndrome
. Velafaxine therapy should be terminated at least seven days prior to the administration of another serotogenic drug
Use of venlafaxine with other amphetamine-like drugs is discouraged by the manufacturer.
[top]Different Uses for Velafaxine
Venlafaxine is used for the treatment of:
-Major Depressive Disorder
-Generalized Anxiety Disorder
[top]Pharmacology of Venlafaxine
Venlafaxine works by blocking the reuptake transporters for norepinephrine and serotonin, allowing the neurotransmitters to remain in the synaptic cleft for an extended period of time and continue to stimulate the post-synaptic neuron. Venlafaxine also appears to weakly inhibit dopamine reuptake in the frontal cortex of the brain at higher doses of 300mg+
Venlafaxine is metabolized by the liver with O-desmethylvenlafaxine as the major active metabolite. It is eliminated by the kidneys with approximately 87% of dose recovered in the urine after 48 hours.
is approximately 5 hours with O-desmethylvenlafaxine, venlafaxine's active metabolite, having a half-life of approximately 11 hours.
[top]Chemistry of Venlafaxine
|Systematic (IUPAC) name:||1-[2-Dimethylamino)-1-(4-methoxyphenyl)ethyl]cyclohexanol|
|Synonyms:||(±)-1-[[alpha]-[(dimethylamino)-methyl]-p-methoxybenzyl]cyclohexanol, N,N-dimethyl-2-(1-hydroxycyclohexyl)-2-(4-methoxyphenyl)ethylamine, venlafexine; Wy-45030, Effexor (hydrochloride); Wy-45655 ((+)-form hydrochloride); Wy-45651 ((-)-form hydrochloride)|
|Molar mass:|| 277.41 g/mol, 313.87 g/mol (hydrochloride)|
|CAS Registry Number:||93413-69-5, 99300-78-4 (hydrochloride)|
|Melting Point:||215-217°C (hydrochloride), 102-104°C ((+)/(-)-form), 240-240.5°C ((+)/(-)-form hydrochloride)|
|Boiling Point:||no data|
|Flash Point:||no data|
|Solubility:||hydrochloride solubility in water 572 mg/mL|
|Additionnal data:||hydrochloride partition coefficient (octanol/water) 0.43|
|Notes:|| Hydrochloride white to off-white crystalline solid from methanol/ethyl acetate; (+)/(-)-form crystals from ethyl acetate; (+)/(-)-form hydrochloride crystals from methanol/ether|
[top]The Dangers of Venlafaxine
Overdose on venlafaxine commonly occurs in conjunction with other drugs. Symptoms of overdose include tachycardia
, somnolence, coma, mydriasis, seizures, vomiting, EKG changes, ventricular tachycardia, bradycardia, hypotension, rhabdomyolysis
, vertigo, liver necrosis, serotonin syndrome, and death . The potential for fatal overdose with venlafaxine is lower than with tricyclic antidepressants but higher than SSRIs.
[top]Mental health risks
Some users of venlafaxine may experience a worsening of depressive symptoms leading to suicidal ideation.
Anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, akathisia, hypomania, and mania, have been reported with the use of venlafaxine. Screening for bipolar disorder should be completed prior to venlafaxine administration to minimize the potential of these symptoms appearing.
[top]Physical Addiction of Venlafaxine
Adverse physical reactions that have occurred with the withdrawal
of venlafaxine include:
-Abnormal ejaculation or impotence in men
[top]Mental Addiction of Venlafaxine
Common adverse psychological reactions to venlafaxine withdrawal include:
[top]Forms of Venlafaxine
Venlafaxine is prescribed in capsules or pressed tablets of 25mg, 37.5mg, 50mg, 75mg or 100mg. Extended release version comes in 37.5mg, 75mg, 150mg and 225mg capsules.
[top]Legal Status of Venlafaxine
Venlafaxine is available for prescription in the United States
[top]History of Venlafaxine
Wyeth Pharmaceuticals synthesized Venlafaxine in the early 1980s but it was not approved by the FDA until early 1994. The first formulation was immediate release, with an extended released approved by 1997.
[top]Popularity of Venlafaxine over time
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[top]The Latest VenlafaxineThreads
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