Effexor (venlafaxine hydrochloride) is a structurally novel antidepressant for oral administration. It is designated (R/S)-1-[2-(dimethylamino)-1-(4-methoxyphenyl)ethyl] cyclohexanol hydrochloride or (±)-1-[a-[(dimethyl-amino)methyl]-p-methoxybenzyl] cyclohexanol hydrochloride and has the empirical formula of C₁₇H₂₇NO₂ HCl. Its molecular weight is 313.87.The structural formula is shown below.
Velafaxine hydrocloride
Venlafaxine hydrochloride is a white to off-white crystalline solid with a solubility of 572 mg/mL in water (adjusted to ionic strength of 0.2 M with sodium chloride). Its octanol:water (0.2 M sodium chloride) partition coefficient is 0.43.Compressed tablets contain venlafaxine hydrochloride equivalent to 25 mg, 37.5 mg, 50 mg, 75 mg, or 100 mg venlafaxine. Inactive ingredients consist of cellulose, iron oxides, lactose, magnesium stearate, and sodium starch glycolate.
Drug Uses

Effexor XR is a potent inhibitor of the reuptake of serotonin and norepinephrine-two neurotransmitters thought to play important roles in the pathophysiology of depression. Correcting the imbalance of these two chemicals may help relieve symptoms of depression.
How Taken
Effexor XR comes as a capsule to take by mouth. It is usually taken once a day and should be taken with food. Each capsule should be swallowed whole with fluid and not divided, crushed, chewed, or placed in water, or it may be administered by carefully opening the capsule and sprinkling the entire contents on a spoonful of applesauce. This drug/food mixture should be swallowed immediately without chewing and followed with a glass of water to ensure complete swallowing of the pellets.
Warnings/Precautions
Before starting Effexor XR, tell your doctor about any medicines you’re taking, including over-the-counter drugs and herbal supplements. If you take MAOIs you should not take Effexor XR. If you are taking antidepressants you should be watched closely for signs that your condition is getting worse or that you are becoming suicidal, especially when you first start therapy, or when your dose is increased or decreased. You should also be watched for becoming agitated, irritable, hostile, impulsive, or restless. Such symptoms should be reported to your doctor right away. Effexor XR may raise blood pressure in some patients, so blood pressure should be monitored regularly. When you suddenly stop using or quickly lower your daily dose of Effexor XR, discontinuation symptoms may occur. Talk to your doctor before discontinuing or reducing your dose of Effexor XR. Pregnant or nursing women shouldn’t take any antidepressant without consulting their doctor. Until you see how Effexor XR affects you, be careful doing such activities as driving a car or operating machinery. Avoid drinking alcohol while taking Effexor XR.
Missed Dose
Take the missed dose as soon as you remember. However, if it is almost time for the next dose, skip the missed dose and take only the next one as directed. Do not take a double dose of this medication.
Possible Side Effects
If you experience any of the following serious side effects, stop taking Effexor XR and contact your doctor immediately or seek emergency medical treatment: an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives); seizures; or an irregular heartbeat or severely high blood pressure (blurred vision, headache). Other, less serious side effects may be more likely to occur. Continue to take Effexor XR and talk to your doctor if you experience nausea, vomiting, upset stomach, abdominal pain, or loss of appetite or weight; dry mouth; drowsiness or dizziness; mild tremor, anxiety, or agitation; insomnia; abnormal dreams; sexual problems such as impotence, abnormal ejaculation, difficulty reaching orgasm, or decreased libido; sweating; yawning; or increase in blood cholesterol levels (detected by blood tests); Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.
Storage
Store Effexor XR at room temperature (68F to 77F or 20C to 25C). Keep Effexor XR away from children.
Overdose
Seek emergency medical attention if an overdose is suspected. Symptoms of an Effexor XR overdose may include dizziness, drowsiness, numbness, nausea, irregular heartbeats, seizures, and unconsciousness.
More Information
Use caution when driving, operating machinery, or performing other hazardous activities. Effexor XR may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities. Use alcohol cautiously. Alcohol may increase drowsiness, dizziness, and confusion Do not stop taking Effexor XR without first talking to your doctor. Your doctor may need to gradually reduce the dose before stopping the medication completely. Stopping the medication suddenly may cause unpleasant side effects to occur.