Venlafaxine

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Benjamin Clanner-Engelshofen is a freelance writer in the medical department. He studied biochemistry and pharmacy in Munich and Cambridge / Boston (USA) and noticed early on that he particularly enjoyed the interface between medicine and science. That is why he went on to study human medicine.

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The antidepressant venlafaxine belongs to the group of selective serotonin-norepinephrine reuptake inhibitors. It is used for the drug treatment of depression and anxiety disorders, in the form of a tablet or capsule. Venlafaxine can cause side effects such as headache and gastrointestinal discomfort. Here you can read everything important about the effect of venlafaxine, side effects and use.

This is how venlafaxine works

Venlafaxine is a drug from the group of selective serotonin-norepinephrine reuptake inhibitors (SSNRIs). It has an antidepressant (mood-enhancing) effect and increases drive.

The two messenger substances serotonin and noradrenaline transmit nerve signals between the brain cells by being released from one cell and then binding to certain docking points (receptors) of the next cell. The messenger substances are then taken up again in the first nerve cell and thus inactivated.

Venlafaxine inhibits this reuptake, which means that norepinephrine and serotonin remain active and therefore effective for longer. The result is a mood-enhancing and drive-enhancing effect. There is usually a time lag of about two weeks before it works.

Uptake, breakdown and excretion

Venlafaxine is usually used in salt form as venlafaxine hydrochloride. After ingestion through the mouth, it is absorbed into the blood through the intestinal wall and metabolized primarily through the liver. The bioavailability is around 45 percent (i.e. 45 percent of the amount of active ingredient ingested through the mouth can be used by the body). After being metabolized by the liver, venlafaxine is largely excreted by the kidneys.

The maximum concentration of venlafaxine in the blood serum is reached about two hours after ingestion. If taken several times, the blood level will reach constant values after about three days.

When is venlafaxine used?

Venlafaxine is approved for:

Depression including maintenance therapy to prevent new episodes of depression from recurring

Generalized anxiety disorder
Social anxiety disorder (social phobia)
Panic disorder with / without claustrophobia (agoraphobia)

This is how venlafaxine is used

Venlafaxine is used in oral form as a tablet or capsule with or without delayed release of the active ingredient (retardation). Delayed-release preparations are only taken once a day, and those without delayed-release two to three times a day.

In the case of depressive syndromes and generalized anxiety disorder, therapy usually starts with a dose of 75 milligrams per day. If necessary, the doctor can increase the dose to 150 milligrams per day. The maximum dose is 375 milligrams per day.

The regular intake of venlafaxine is important for the success of the therapy, as otherwise the amount of active norepinephrine and serotonin outside the nerve cells can decrease.

If you want to stop taking venlafaxine, this should be done by gradually reducing the daily dose ("tapering off"). Abrupt abortion can cause withdrawal symptoms such as psychological changes (feelings of fear, confusion, perception disorders), neurological disorders (headache, dizziness, sensory disorders), vegetative disorders and loss of appetite.

What side effects does venlafaxine have?

Very often (i.e. in more than one in ten people) taking venlafaxine causes headache, gastrointestinal disorders (such as nausea, vomiting and constipation), sweating, dry mouth and an increased risk of tooth decay due to dry mouth.

Rarely (in one in ten to one hundred people treated), weight loss, unusual dreams, insomnia and decrease in sexual desire (loss of libido) occur when taking venlafaxine.

Occasionally (in one in hundred to one thousand people treated) venlafaxine can cause weight gain, skin reactions, orgasmic disorders in women, and changes in taste.

What should be considered when taking venlafaxine?

Contraindications

Venlafaxine is contraindicated in:

Hypersensitivity to the active ingredient or any of the other ingredients

Concomitant use of a monoamine oxidase inhibitor (MAO inhibitor) due to the risk of serotonin syndrome

Serotonin syndrome is a life-threatening condition with an increase in blood pressure, agitation, convulsions and body overheating.

The antidepressant should be used with caution in the following cases:

Thoughts of suicide (venlafaxine increases drive before its antidepressant effects occur)
epilepsy
increased pressure in the eye (glaucoma)

interaction

There may be interactions with other drugs that are used at the same time, for example with:

Medicines to suppress the immune system (immunosuppressants such as tacrolimus, ciclosporin, sirolimus)
Antifungal agents (antifungals such as lotrimazole, ketoconazole, itraconazole)
various antidepressants (e.g. amitriptyline, clomipramine, imipramine, citalopram, escitalopram, fluoxetine, norfluoxetine, sertraline)
strong painkillers from the group of opiates / opioids (e.g.Alfentanil, codeine, fentanyl, methadone)
Cholesterol lowering drugs (statins such as atorvastatin, lovastatin, simvastatin)
Erectile dysfunction agents (Sildenafil, Tadalafil, Vardenafil)

Especially at the beginning of treatment and when stopping venlafaxine, judgment and reactions may be impaired.

Age restriction

Venlafaxine is not recommended for the treatment of children and adolescents under 18 years of age. The effectiveness and safety of the active ingredient have not been adequately proven in this age group.

pregnancy and breast feeding period

Various studies have shown no evidence of an increased risk of malformations when using venlafaxine. The use can therefore be continued during pregnancy if the setting is stable.

In previous publications on the use of venlafaxine during breastfeeding, no adverse effects were observed in the breastfed children. However, venlafaxine and its metabolites pass into breast milk and can lead to crying, restlessness and altered sleep behavior in the infant.

In the case of new depression during pregnancy and breastfeeding, preference should be given to one of the better-studied active ingredients, citalopram and sertraline.

How to get medication with venlafaxine

Venlafaxine requires a prescription in all doses in Germany, Austria and Switzerland. It may only be taken on medical advice.

Since when has venlafaxine been known?

Venlafaxine was approved in Germany in 1995 as the first drug from the group of selective serotonin-norepinephrine reuptake inhibitors. At first it was approved for the therapy of depression; later other areas of application were added.

The patent expired in December 2008. Since then, numerous generics (preparations with identical active ingredients) have come onto the market.

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