Venlafaxine 100mg Tablets

Venlafaxine and its active metabolite, O-desmethylvenlafaxine (ODV), are potent inhibitors of neuronal serotonin and norepinephrine reuptake and a weak inhibitor of dopamine reuptake. This leads to increased concentrations of these neurotransmitters in the synaptic cleft, enhancing their activity in the central nervous system.

Urgent Side Effects: Seek Medical Help Right Away

Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:

Signs of an allergic reaction, such as:
+ Rash or hives
+ Itching or red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing or tightness in the chest or throat
+ Difficulty breathing, swallowing, or talking
+ Unusual hoarseness or swelling of the mouth, face, lips, tongue, or throat
Signs of low sodium levels, including:
+ Headache
+ Trouble focusing or memory problems
+ Feeling confused or weak
+ Seizures or changes in balance
Signs of bleeding, such as:
+ Vomiting or coughing up blood
+ Vomit that resembles coffee grounds
+ Blood in the urine
+ Black, red, or tarry stools
+ Bleeding from the gums
+ Abnormal vaginal bleeding
+ Unexplained bruises or bruises that enlarge
+ Uncontrollable bleeding
Signs of high blood pressure, including:
+ Severe headache or dizziness
+ Fainting or changes in vision
Seizures
Chest pain or pressure
Shortness of breath
Cough
Bone pain
Sexual problems, such as:
+ Decreased interest in sex
+ Difficulty having an orgasm
+ Ejaculation problems
+ Trouble getting or maintaining an erection
A potentially life-threatening condition called serotonin syndrome, which may be more likely if you take certain other medications. Seek medical help immediately if you experience:
+ Agitation
+ Changes in balance
+ Confusion
+ Hallucinations
+ Fever
+ Rapid or abnormal heartbeat
+ Flushing
+ Muscle twitching or stiffness
+ Seizures
+ Shivering or shaking
+ Excessive sweating
+ Severe diarrhea, stomach upset, or vomiting
+ Severe headache

Other Possible Side Effects

Like all medications, this drug can cause side effects. While many people may not experience any side effects or only mild ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other symptoms that bother you or persist, contact your doctor:

Difficulty sleeping
Feeling nervous, anxious, or excitable
Weight loss
Dizziness, drowsiness, tiredness, or weakness
Shakiness
Headache
Excessive sweating
Constipation, diarrhea, stomach upset, vomiting, or decreased appetite
Gas
Dry mouth
Strange or unusual dreams
* Yawning

Reporting Side Effects

This list is not exhaustive, and you may experience other side effects. If you have questions or concerns, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.

Before Taking This Medication: Important Information to Share with Your Doctor

It is essential to inform your doctor about the following conditions and situations to ensure safe treatment:

Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction and its symptoms.
If you have high blood pressure, as this may be relevant to your treatment.
If you have narrow-angle glaucoma, a condition that affects the eyes.
If you are currently taking a weight loss medication, as this may interact with the prescribed drug.
If you are taking or have recently taken certain medications, including:
+ Linezolid or methylene blue, as these can interact with the prescribed medication.
+ Certain drugs for depression or Parkinson's disease, such as isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline, within the last 14 days. Taking these medications together can lead to very high blood pressure.
Other health problems or medications that may interact with the prescribed drug, including prescription and over-the-counter medications, natural products, and vitamins.

To ensure your safety, it is crucial to provide your doctor and pharmacist with a comprehensive list of all your medications and health problems. This will help them determine whether it is safe for you to take this medication with your other treatments. Never start, stop, or change the dose of any medication without consulting your doctor first.

It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. This will help ensure your safety and prevent any potential interactions with other treatments.

Until you know how this medication affects you, avoid driving and other activities that require you to be alert. This is crucial to prevent accidents and ensure your safety.

Do not stop taking this medication abruptly without consulting your doctor, as this may increase your risk of side effects. In some cases, these side effects can be severe and long-lasting. If you need to discontinue this medication, your doctor will guide you on how to gradually stop taking it. Be sure to discuss any new or worsening symptoms with your doctor.

Regular blood pressure checks are necessary while taking this medication, as it may cause high blood pressure. Your doctor will advise you on the frequency of these checks.

It is recommended to avoid consuming alcohol while taking this medication. Additionally, consult your doctor before using marijuana, cannabis, or any prescription or over-the-counter medications that may cause drowsiness.

This medication may increase the risk of bleeding, which can be life-threatening in some cases. Discuss this risk with your doctor, especially if you have any concerns.

If you have bipolar disorder, be aware that this medication may trigger manic episodes. Contact your doctor immediately if you experience any symptoms of a manic episode.

Some individuals may be at a higher risk of developing eye problems while taking this medication. Your doctor may recommend an eye exam to assess this risk. If you experience eye pain, changes in vision, or swelling and redness in or around the eye, seek medical attention promptly.

Low blood sodium levels (hyponatremia) can occur with this medication, and in severe cases, it can be fatal. Discuss this risk with your doctor and report any concerns.

High cholesterol has been reported in some individuals taking this medication. If you have questions or concerns, consult your doctor.

This medication may affect certain laboratory tests. Inform all your healthcare providers and laboratory personnel that you are taking this medication to ensure accurate test results.

If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.

In children and adolescents, this medication may affect growth in some cases. Regular growth checks may be necessary, and your doctor will discuss this with you.

If you are pregnant, plan to become pregnant, or are breastfeeding, consult your doctor to discuss the benefits and risks of taking this medication. Taking this medication in mid to late pregnancy may lead to health problems in the mother (such as postpartum bleeding) or the newborn. Your doctor will help you weigh the risks and benefits and make an informed decision.

• Monoamine Oxidase Inhibitors (MAOIs) - risk of serious, sometimes fatal, serotonin syndrome. Must allow at least 14 days between discontinuing an MAOI and starting venlafaxine, and at least 7 days between discontinuing venlafaxine and starting an MAOI.

• Other serotonergic drugs (e.g., SSRIs, SNRIs, triptans, fentanyl, lithium, tramadol, tryptophan, buspirone, St. John's Wort) - increased risk of serotonin syndrome.
• Drugs that impair metabolism of venlafaxine (e.g., strong CYP2D6 inhibitors like quinidine, fluoxetine, paroxetine) - may increase venlafaxine levels and decrease ODV levels, potentially altering efficacy/safety.
• Drugs that increase bleeding risk (e.g., NSAIDs, aspirin, warfarin, other anticoagulants) - increased risk of abnormal bleeding due to venlafaxine's effect on serotonin uptake by platelets.
• Linezolid (antibiotic with MAOI activity) - risk of serotonin syndrome.
• Methylene blue (IV formulation) - risk of serotonin syndrome.

• Alcohol - may enhance CNS depressant effects and impair psychomotor skills.
• Cimetidine - may inhibit first-pass metabolism of venlafaxine, increasing AUC.
• Haloperidol - venlafaxine may increase haloperidol AUC and Cmax.
• Metoprolol - venlafaxine may increase metoprolol plasma levels.
• Indinavir - venlafaxine may decrease indinavir AUC and Cmax.
• Drugs that prolong QT interval - theoretical risk, though venlafaxine's effect on QTc is generally small.

• Not available

• Mood changes (improvement or worsening)
• Anxiety levels
• Sleep patterns (insomnia or somnolence)
• Appetite changes
• Energy levels
• Agitation or restlessness
• Irritability
• Panic attacks
• New or worsening suicidal thoughts or behaviors
• Unusual changes in behavior
• Headache
• Nausea/vomiting
• Dizziness
• Dry mouth
• Sweating
• Sexual dysfunction
• Symptoms of serotonin syndrome (e.g., confusion, rapid heart rate, muscle stiffness, sweating, fever)
• Symptoms of discontinuation syndrome (e.g., dizziness, nausea, headache, paresthesias, anxiety, insomnia, tremor, flu-like symptoms)

Use during pregnancy should be considered only if the potential benefit justifies the potential risk to the fetus. Neonates exposed to SNRIs late in the third trimester have developed complications requiring prolonged hospitalization, respiratory support, and tube feeding.

Venlafaxine and its active metabolite (ODV) are excreted into breast milk. The decision to breastfeed should consider the developmental and health benefits of breastfeeding, the mother’s clinical need for venlafaxine, and any potential adverse effects on the breastfed infant from venlafaxine or from the underlying maternal condition. Monitor infants for sedation, poor feeding, and poor weight gain.

Safety and efficacy have not been established in pediatric patients. Antidepressants, including venlafaxine, increase the risk of suicidal thoughts and behavior in children, adolescents, and young adults (see Black Box Warning). Use is generally not recommended.

No overall differences in effectiveness or safety were observed between geriatric and younger patients, but greater sensitivity of some older individuals cannot be ruled out. Elderly patients may be at increased risk for hyponatremia and falls. Use lower initial doses and titrate slowly. Monitor for adverse effects, especially blood pressure and hyponatremia.

• Venlafaxine immediate-release (IR) requires multiple daily doses (2-3 times/day) due to its shorter half-life, which can lead to more pronounced withdrawal symptoms if doses are missed or discontinued abruptly. Extended-release (XR) is generally preferred for once-daily dosing and better tolerability.
• Always titrate venlafaxine doses slowly to minimize side effects, especially nausea, dizziness, and blood pressure increases.
• Monitor blood pressure regularly, as venlafaxine can cause dose-dependent hypertension, particularly at higher doses.
• Be vigilant for symptoms of serotonin syndrome, especially when co-prescribing with other serotonergic agents.
• Educate patients thoroughly about the importance of not stopping venlafaxine suddenly due to the risk of severe discontinuation syndrome (e.g., 'brain zaps', dizziness, nausea, anxiety).
• Consider genetic testing for CYP2D6 poor metabolizers, as they may have higher venlafaxine levels and lower ODV levels, potentially affecting efficacy and side effects, though routine testing is not universally recommended.

• Other SNRIs (e.g., Duloxetine, Desvenlafaxine, Levomilnacipran)
• SSRIs (e.g., Fluoxetine, Sertraline, Paroxetine, Citalopram, Escitalopram)
• Atypical antidepressants (e.g., Bupropion, Mirtazapine, Trazodone)
• Tricyclic Antidepressants (TCAs) (e.g., Amitriptyline, Nortriptyline)
• Monoamine Oxidase Inhibitors (MAOIs) (e.g., Phenelzine, Tranylcypromine, Selegiline)
• Psychotherapy (e.g., Cognitive Behavioral Therapy - CBT)

If your symptoms or health issues persist or worsen, it's essential to contact your doctor promptly. To ensure safe use, never share your medication with others or take someone else's medication. This medication is accompanied by a Medication Guide, which provides crucial information. Please read this guide carefully and review it again whenever you receive a refill. If you have any questions or concerns about this medication, don't hesitate to consult with your doctor, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide details about the medication taken, the amount, and the time it occurred.