Venlafaxine

Venlafaxine is a prescription medication used to treat adults with major depressive disorder, panic disorder, and anxiety. It belongs to a class of drugs called serotonin norepinephrine reuptake inhibitors (SNRIs). These work by increasing serotonin and norepinephrine levels, which are natural substances in the brain that help maintain mental balance.

Venlafaxine is available as immediate-release and extended-release tablets. It also comes in extended-release capsule form. The immediate-release tablet is usually taken 2 or 3 times a day with food. Extended-release tablets and capsules are taken once a day with food.

Common side effects of venlafaxine include dry mouth, insomnia, loss of appetite, and dizziness. Do not drive or operate heavy machinery until you know how venlafaxine will affect you.

CYP2D6 is a protein in your body that is involved in the elimination of venlafaxine and other drugs from your body. Some patients have less of this protein in their bodies, affecting how much of the drug gets eliminated. Levels of CYP2D6 can vary greatly between individuals, and those having less of this protein are known as "poor metabolizers." 

CYP2D6 testing is done to determine whether you are a poor metabolizer. If you are a poor metabolizer, the levels of venlafaxine in your blood can become too high. As a result you may be at an increased risk of having more side effects from venlafaxine. 

Your doctor may adjust your dose of venlafaxine if you are a poor metabolizer.

Venlafaxine is a prescription medication used to treat adults with depression. The extended-release form is also approved to treat anxiety disorders, and panic disorder.

Venlafaxine may be found in some form under the following brand names:

• Effexor

• Effexor XR

Venlafaxine may cause serious side effects. See "Drug Precautions".

Common side effects include:

• constipation
• dizziness
• dry mouth
• insomnia
• loss of appetite
• nausea
• nervousness
• sexual side effects
• sleepiness
• sweating
• weakness

This is not a complete list of venlafaxine side effects. Ask your doctor or pharmacist for more information.

Tell your doctor about all the medicines you are taking including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you are taking:

• MAOIs such as isocarboxazid and phenelzine 
• Alcohol 
• Fluoxetine 
• Citalopram 
• Sertraline 
• Amitriptyline 
• Doxepin 
• Lithium 
• Tramadol 
• Indinavir 
• Ketoconazole 
• Cimetidine

This is not a complete list of venlafaxine drug interactions. Ask your doctor or pharmacist for more information.

1. Antidepressant medicines may increase suicidal thoughts or actions in some children, teenagers, and young adults within the first few months of treatment.

2. Depression and other serious mental illnesses are the most important causes of suicidal thoughts and actions. Some people may have a particularly high risk of having suicidal thoughts or actions. These include people who have (or have a family history of) bipolar illness (also called manic-depressive illness) or suicidal thoughts or actions.

3. How can I watch for and try to prevent suicidal thoughts and actions in myself or a family member?

• Pay close attention to any changes, especially sudden changes, in mood, behaviors, thoughts, or feelings. This is very important when an antidepressant medicine is started or when the dose is changed.
• Call the healthcare provider right away to report new or sudden changes in mood, behavior, thoughts, or feelings.
• Keep all follow-up visits with the healthcare provider as scheduled. Call the healthcare provider between visits as needed, especially if you have concerns about symptoms.

Do not take venlafaxine if:

• you have taken an MAO inhibitor in the last 2 weeks
• you have a history of mania, seizures, or kidney problems

Venlafaxine may make you drowsy. Do not drive or operate heavy machinery until you know how this medication affects you.

Medicines can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of venlafaxine there are no specific foods that you must exclude from your diet when receiving venlafaxine.

Before receiving this medication, tell your doctor about all your medical conditions especially:

• bipolar disorder
• heart disease or high blood pressure
• epilepsy
• glaucoma
• liver or kidney disease
• blood clotting disorder (bleeding disorder)

Tell your doctor about all the medicines you take or are planning to take including prescription and non-prescription medicines, vitamins, and herbal supplements.

Tell your doctor if you are pregnant, planning to become pregnant or breastfeeding.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

This medication falls into category C. In animal studies, pregnant animals were given this medication and had some babies born with problems. No well-controlled studies have been done in humans. Therefore, this medication may be used if the potential benefits to the mother outweigh the potential risks to the unborn child.

Tell your doctor if you are breastfeeding or planning to breastfeed. Venlafaxine may be excreted in human breast milk and may harm your nursing baby.

Venlafaxine tablets or capsules should be taken with food, at the same time(s) each day.

Do not suddenly stop taking venlafaxine without talking to your doctor first. Abruptly stopping venlafaxine can cause withdrawal symptoms (unpleasant side effects).

If you miss a dose, take the missed dose as soon as you remember. If it is almost time for the next dose, skip the missed dose and take your next dose at the regular time. Do not take two doses of venlafaxine at the same time.

Take venlafaxine exactly as your doctor prescribes it. Follow the directions on your prescription label carefully. The dose will depend on several factors including the condition being treated, response to the medicine, and how well the medicine is tolerated.

The usual starting dose is 75 mg per day (divided into two or three smaller doses for short-acting venlafaxine). Some patients will need to be started on 37.5 mg per day and after 4 to 7 days increased to 75 mg per day. Dose increases of up to 75 mg per day may be necessary.

The recommended maximum daily dose is 225 mg, although some patients may require as much as 350 mg per day.

If you take too much venlafaxine call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away.

If venlafaxine is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if overdose is suspected, seek emergency medical attention.

• Store at controlled room temperature.
• Keep all medications out of the reach of children.

Suicidality and Antidepressant Drugs

Antidepressants increased the risk compared to placebo of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults in short-term studies of Major Depressive Disorder (MDD) and other psychiatric disorders. Anyone considering the use of venlafaxine or any other antidepressant in a child, adolescent, or young adult must balance this risk with the clinical need. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared to placebo in adults beyond age 24; there was a reduction in risk with antidepressants compared to placebo in adults aged 65 and older. Depression and certain other psychiatric disorders are themselves associated with increases in the risk of suicide. Patients of all ages who are started on antidepressant therapy should be monitored appropriately and observed closely for clinical worsening, suicidality, or unusual changes in behavior. Families and caregivers should be advised of the need for close observation and communication with the prescriber. Venlafaxine is not approved for use in pediatric patients.