Dosages increase by 37.5mg after 2-3 weeks to a therapeutic range which is 150mg. For some, effects have taken place at lower doses therefore that would YOUR therapeutic range. I'm on 37.5mg once a day for 2 weeks with minimal side effects. Will continue to increase the dosage by 37.5mg once a day until I reach my therapeutic range. Effexor is NOT recommended for teenagers and below b/c the. The therapeutic dosage (the amount of a medication one must take for it to have it's intended clinical effect) varies from person to person. This is true of all medications and therefore is true for Effexor. yer i see that alot of people are on around about 225-400mg so it must be a good dose range, i just hope i dont get a mild case of seritonum syndrome like i did when i was on lexapro and increased to 20mg. Medscape - Depression-specific dosing for Effexor, Effexor XR (venlafaxine), frequency-based adverse effects, comprehensive interactions, contraindications, pregnancy & lactation schedules, and cost information. The therapeutic range for venlafaxine includes measurement if O-desmethylvenlafaxine; optimal response is seen when combined concentrations of parent and metabolite are between 195 and 400 ng/mL. Venlafaxine is significantly affected by reduced hepatic function, but only slightly by reduced renal function. Therapeutic range defines the quantitative measurement of a prescription medication’s dosage level by regularly evaluating and correlating distinctions between the efficacy and toxicity of the concentration of a drug within the serum or plasma of the bloodstream. Depressed patients who are currently being treated at a therapeutic dose with Effexor (immediate release) may be switched to Effexor XR at the nearest equivalent dose (mg per day), e.g., 37.5 mg venlafaxine twice a day to 75 mg Effexor XR once daily. However, individual dosage adjustments may be necessary. The therapeutic index (TI; also referred to as therapeutic ratio) is a comparison of the amount of a therapeutic agent that causes the therapeutic effect to the amount that causes toxicity. The related terms therapeutic window or safety window refer to a range of doses which optimize between efficacy and toxicity, achieving the greatest. Depressed patients who are currently being treated at a therapeutic dose with Effexor (immediate release) may be switched to Effexor XR at the nearest equivalent dose (mg per day), e.g., 37.5 mg venlafaxine twice a day to 75 mg Effexor XR once daily. However, individual dosage adjustments may be necessary. You are taking a very low dose of lamotrigine (therapeutic range is generally 100 - 400 mg a day). Neurontin is pretty clean in terms of drug interactions. So I don't think you need to be too concerned about drug interactions from adding either Buspar or Effexor.