Wednesday, October 19, 2011

Usage and side effects of Venlafaxine (Venlift, Venlamax, Vexor, Venla, Venjoy, Venfax, Vendep, Sentosa, Flavix and Dallium)

Venlafaxine is a medication prescribed for major depression and anxiety disorders. In addition, it is prescribed for chronic pain syndromes such as neuropathic pain and fibromyalgia. Commonest Indian brand names are Venlift, Venlamax, Vexor, Venla, Venjoy, Venfax, Vendep, Sentosa, Flavix and Dallium. In US it is sold as Effexor.

Its commonest side effects are dry mouth, reduced sleep and constipation. Venlafaxine XR is the extended release preparation of the Venlafaxine. Therefore, Patients usually get minimal side effects with Venlafaxine XR compared to Venlafaxine.

How Venlafaxine works?

Venlafaxine works by increasing natural neurotransmitters serotonin and noradrenalin inside certain brain areas. However, side effects are due to increased noradrenalin and serotonin levels in unwanted areas of the brain.

What are the common side effects Venlafaxine ?

Constipation, nausea, loss of appetite, diarrhea, gastritis, vomiting, and abdominal pain are most common side effects. Patients can get increased blood pressure as a side effect.  Sometimes palpitations (feeling one’s own heart beat associated with distress) can occur.

Dizziness, dry mouth, insomnia, nervousness, and headache are other common side effects. In addition, patients can complain abnormal dreams. Short term anxiety and agitation is also common.

Sexual dysfunction is another problematic side effect that can leads to poor drug compliance. Women in reproductive age, taking Venlafaxine may complain menstrual irregularities. Muscle pain and joint pain can occur with some patients. Some patients can have pupillary dilatation in their eyes. This can leads to angle closure glaucoma. However compared to other anti-depressants (SSRIs) sexual side effects such as erectile impotence and lack of desire are uncommon.

Venlafaxine (Effexor) capsules

What are the conditions the doctor should know before prescribing Venlafaxine ?

Doctors usually do not prescribe Venlafaxine , when the patient has serious cardiac rhythm abnormalities, uncontrolled hypertension, severe liver diseases, severe renal impairment and pregnancy. Before starting the drug doctor will check your blood pressure, take an electrocardiogram, and check whether you are pregnant (doctor may ask whether you missed a period).

Doctors will prescribe cautiously, when the patient has certain heart diseases. Blood pressure monitoring is essential in heart diseases. In addition the doctor must know whether the patient has epilepsy. If the patient has a bleeding disorder, the doctor should know that as well. Venlafaxine is present in breast milk, so nursing mothers should consult their doctor before taking this drug.

What are rare side effects of Venlafaxine ?

Taste abnormalities, hallucinations, urinary retention, bleeding disorders, hair loss, and hypersensitivity reactions like hives, angioedema, and photo sensitivity can occur with certain patients.

What you should know before taking this drug?

Patients should not drive or operate machinery while on the drug, until they know how this drug will affect them. In addition, Venlafaxine should not be stopped abruptly. If it is stopped suddenly then the patient may get withdrawal symptoms such as gastro intestinal disturbance, headache, tremors, sleep disturbances, and sweating.

Originally published in 

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