Effexor (venlafaxine) Dosage and Side Effects
Effexor, is a prescription drug used to treat depression, anxiety, social phobia, and panic disorder.
Proper Use of this medication
EFFEXOR comes in immediate-release tablets of 25 milligrams (mg), 37.5 mg, 50 mg, 75 mg, and 100 mg, and in extended-release capsules of 37.5 mg, 75 mg, 150 mg, and 225 mg.
If taken as an immediate-release pill, the dose is usually split up and taken two or three times during the day, with food.
If you're taking the extended-release capsules (tablets in the generic form), take your dose at breakfast or dinner, ideally at the same time every day.
You need to swallow the capsule whole: Do not crush, chew, divide, or place it in a liquid.
If you can't ingest the capsule in one take, open it and sprinkle the drug on a soft liquidly food such as pudding or applesauce, swallow the food immediately, and chase it down with a glass of water.
Doctors usually start patients between 37.5 mg to 75 mg a day, gradually increasing dosage to an average maximum of 225 mg a day.
It can take up to two months for EFFEXOR to work.
Do not stop taking the medication without first consulting with your doctor, as stopping EFFEXOR abruptly can bring on anxiety, irritability, fatigue, headaches, vomiting, and tremors.
If you have taken too much EFFEXOR, call your doctor or poison control center immediately, or go straight to an emergency room.
Symptoms of a EFFEXOR overdose include:
- Rapid heart rate
- Blurry vision
- Extreme fatigue
Missed Dose of EFFEXOR
Take the missed dose as soon as you remember, unless it's close to the time for your next dose.
In that case, skip the missed dose and take the next dose at the regular time.
Do not take two doses of EFFEXOR together, and do not take more than one dose of the extended-release capsule or tablet in one day.
Common Side Effects of EFFEXOR
Check with your doctor if these side effects persist, or become overly troublesome:
- Unusual dreams
- Sexual dysfunction
- Drowsiness, weakness, or fatigue
- Dizziness, blurred vision
- Loss of appetite
- Increased sweating
- Dry mouth
- Gas or stomach pain
- Runny nose
- Tremors, shaking, chills
- Tingling sensations
- Weight loss
Serious Side Effects of EFFEXOR
Call your doctor or get immediate medical help if you experience any of these serious side effects:
- Symptoms of serotonin syndrome, including agitation, hallucinations, coma, muscle twitching, rapid heartbeat, compromised coordination, high or low blood pressure, excessive sweating or fever
- Increased cholesterol levels
- Narrow-angle glaucoma, enlarged pupils
- Low-salt (sodium) levels in the blood
- Seizures or convulsions
- Abnormal bleeding, increased bruising
- Severe allergic reactions
- Chest discomfort, or difficulty breathing
EFFEXOR is generally not recommended for children younger than 18 years old, but if it has been prescribed, be aware that studies have suggested that it might slow growth and weight gain, and contribute to suicidal thoughts.
Low sodium in the blood is more likely to occur in elderly patients and those taking diuretics.
EFFEXOR and Weight Gain
Like many other antidepressants, use of EFFEXOR has been associated with weight gain.
Weight gain caused by EFFEXOR may be due to fluid retention, lack of exercise, increased appetite, or other factors.
Experts recommend physical activity and eating fewer high-calorie foods to manage your weight while taking EFFEXOR or other antidepressants.
Allergic Reaction to EFFEXOR
Seek medical help immediately at any sign of an allergic reaction to EFFEXOR:
- Difficulty breathing
- Swelling of the face, tongue, eyes, or mouth
- Rash, itchy hives, or blisters that can occur alone or accompany fever or joint pain
Warnings and Precautions
The FDA has issued a black-box warning for EFFEXOR because studies found an increased risk of suicidal thoughts and behavior in children, teenagers, and young adults taking antidepressants, including Effexor.
EFFEXOR can interact with other prescription or nonprescription medications in ways that hinder its effectiveness or bring on serious side effects.
Tell your doctor if you are taking other antidepressants, including such selective serotonin uptake inhibitors (SSRIs) as Paxil (paroxetine) or Zoloft (sertraline), other SSNRIs such as Cymbalta (duloxetine) or Pristiq (desEFFEXOR), or any monoamine oxidase inhibitors (MAOIs), including Nardil (phenelzine) or Marplan (isocarboxazid), or whether you stopped taking an MAOI within 14 days of beginning EFFEXOR.
You also need to inform your healthcare provider if you take so-called tripan medications such as sumatriptan (Imitrex, Imigran) for migraines, certain painkillers such as Utram (tramadol), the antibiotic linezolid (Zyvox), or intravenous methylene blue, which is used to treat the blood disorder methemoglobinema.
These medications, along with the herbal supplement St. John's wort, raise the level of serotonin in the brain, and when taken in tandem with EFFEXOR can trigger a rare but potentially life-threatening condition called serotonin syndrome.
EFFEXOR might also enhance the anti-blood-clotting effect of such blood thinners as warfarin (Coumadin, Jantoven), as well as aspirin, and non-steroidal anti-inflammatory drugs (NSAIDs), including ibuprofen (Advil, Motrin).
If you stop taking EFFEXOR suddenly, or reduce your dosage, withdrawal symptoms can occur, often within a matter of hours.
EFFEXOR withdrawal symptoms include:
- Anxiety, confusion, or agitation
- Lack of coordination or vertigo
- Nausea, diarrhea, or vomiting
- Sleep disorders or nightmares
- Dry mouth
- Brain zaps (electric-like shocks)
Many of these symptoms can cause severe disorientation, and are especially dangerous to people driving, operating machinery, or engaging in other risky tasks.
Talk to your doctor about any unusual side effects, and follow your doctor's instructions for tapering off or stopping your use of EFFEXOR.
Pregnancy and EFFEXOR
EFFEXOR may cause harm to a developing fetus.
Newborns whose mothers took EFFEXOR in the last three months of pregnancy were reported to experience feeding and breathing problems, and seizures, shakes, jitters, and constant crying immediately following delivery.
For women who take antidepressants in the second and third trimesters of pregnancy, there is a risk that the baby can be born prematurely, according to the National Alliance on Mental Illness.
EFFEXOR does pass into breast milk, but there have been no sufficient studies to determine the risk to the infant, so talk to your doctor if you plan to breastfeed.
Interactions with this medication
EFFEXOR and Alcohol
Do not drink alcohol while taking EFFEXOR, as alcohol can augment the sleepiness effect of the drug.
EFFEXOR and Other Interactions
Since EFFEXOR can induce sleepiness or hinder your ability to think clearly or react quickly, do not drive or operate heavy machinery until you know how Effexor affects you.
Your doctor needs to know about all the medications you take, whether prescription or over-the-counter, vitamins, illegal or recreational drugs, and dietary or herbal supplements, as they can affect how Effexor works, and vice-versa.
EFFEXOR interacts with the following drugs, which should not be taken with Effexor or taken only under close medical supervision:
- Monoamine oxidase inhibitors (MAOIs), including phenelzine sulfate (Nardil), tranylcypromine sulfate (Parnate), isocarboxazid (Marplen), rasagline (Azilect), selegeline (Eldepryl, Emsam)
- Antidepressants, including amitriptyline (Elavil), citalopram (Celexa), fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), fluvoxamine (Luvox)
- Tripans (Imitrex, Imigran, Migriptan)
- Linezolid (Zyvox)
- Cimetidine (Tagamet, Tagamet HB)
- Ketoconazole (Nizoral)
- Ibuprofen (Advil, Motrin)
- Naproxen (Aleve, Naprosyn)
- Warfarin (Coumadin)
- Aspirin (Bayer)
- Lithium (Eskalith, LithoBid)
- Tramadol (Ultram, Ultracet)
- St. John's wort
Other related products
The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.