Have been on effexor (venlafaxine) 3 weeks, aching all over and feel weak. have experienced this when starting effexor (venlafaxine) once before . is this a normal side effect?

Weakness/effexor: These are not usual symptoms/effects. When it happened before how did it resolve? Discuss with your doctor today, or be seen in urgent care TODAY Effexor (venlafaxine) may not be the drug for you.May consider having your CPK checked. Make sure it is not subclinical/pre serotonin syndrome( usually that is a more noticable effect with brisk reflexes ,high fever).

It could: Be. You stated you has similar problems before. So it probably your body adjusting to the medicine. Usually with this medicine the side effects lessen and eventually dissipate as the levels adjust in your body. Talk with your doctor so they can monitor you. If symptoms worsen stop the medicine.

Yes.: Effexor (venlafaxine) causes many side effects when started and when stopping. It should start to get better. I suggest talking to your prescribing provider. Hope you feel better.

Can see both: The fatigue/weakness is actually relatively common. The muscle aches are less common but still reported.

Unusual but possible: If the Effexor (venlafaxine) was continued and the aching went away this is possible - if you discontinued the Effexor (venlafaxine) last time in order for the aching to go away then stop it again and consult the prescribing physician - Regardless let the prescribng physician know

No: Most people tolerate effexor (venlafaxine) with minimal side effects. You may need a lower dose

No !: However it may happen if you take other drugs such as psychostimulants, pseudoephedrine, use alcoholic drinks, or street drugs.

Not common: Your symptoms are not one of the more common side effects of Effexor (venlafaxine). If these symptoms persist, discuss with GP.