We often receive questions wondering what the correct dosage of different anxiety medications. It certainly can be confusing with so many different medications and each medication having a different dosing structure.
While this is a question that should be discussed with your physician, Dr. Matthew White, the clinical instructor of Psychiatry and Behavioral Science-Behavioral Medicine at Stanford University in California, published information on the most effective dose of medications for social anxiety disorder, generalized anxiety disorder (GAD) and panic disorder: "Medication Dosing in Anxiety Disorders: What the Evidence Shows."
It is also important to note that many of the medications have a range of doses that are effective because of the difference in the severity of symptoms and because each person reacts differently to medications.
Clonazepam (Klonopin), at an average dose of 2.4 mg/day, using twice daily dosing
Alprazolam (Xanax), at an average dose of 4.2 mg/day, using four divided doses
- Paroxetine (Paxil), with a range between 20-40 mg/day. Different studies showed 20, 36, 40 and44 mg to be effective, therefore a range is indicated. Higher doses of 60 mg was not found to be more effective. The controlled release for this medication was found to be effective at 32 mg.
- Sertraline (Zoloft) was effective at between 99 mg and 180 mg.
- Escitalopram (Lexapro), at an average dose of 18 mg wit 5 mg to be a good starting point with increased doses up to 20 mg as needed.
- Fluvoxamine (Luvox) was effective at average doses of 150 mg in one study and 202 mg in a second study.
- Venlafaxine ER (Effexor) showed improved symptoms in average doses ranging from 152 to 202 mg/day.
- Mirtazapine (Remeron) was found to be effective at 30 mg/day in a small, women only study
- Gabapentin (Fanatrex, Gabarone, Neurontin) was used in minimum doses of 900 mg/day and maximum doses of 3600 mg/day (divided into 3 doses) and was found to be effective
- Pregabalin (Lyrica) was found to be effective at 600 mg/day divided into three doses per day
Generalized Anxiety Disorder
- Alprazolam (Xanax)was found to be effective for GAD at 1.5 mg, 1.9 mg and 2.0 mg, in four divided doses
- Lorazepam (Ativan) was effective at 2.0 mg, 3 mg, 3.6 mg, 4 mg and 6 mg.
- Diazepam (Valium, Valrelease), at 15 mg per day, divided into 3 equal doses throughout the day. Additional studies found this medication to be effective at 20 mg, 21 mg and 26 mg.
- Paroxetine (Paxil), at an average dose of between 20 mg and 50 mg, however a second study showed 20 mg to be ineffective so this may be a starting point and effective doses may be closer to 40 mg.
- Escitalopram (Lexapro), at a dose between 10 mg and 20 mg.
- Venlafaxine ER (Effexor), at an average dose of between 151 mg and 171 mg. Some studies show this medication to be effective at a dose of 75 mg and some found 37.5 to be effective in some people.
- Duloxetine (Cymbalta) was effective in a range of between 60 and 120 mg
This medication (Buspar, Vanspar) was effective for GAD at 15 mg, 19 mg, and 25mg, 30 mg divided two or three times per day.
Pregabalin (Lyrica) was effective at between 300, 450 and 600 mg per day, with three doses per day
This medication (Anx, Atarax, Atazine, Hypam, Rezine, Vistaril) was found to be effective in a total dose of 50 mg per day, in three doses of 12.5 mg, 12.5 mg and the third dose at 25 mg.
- Alprazolam (Xanax), at an average of 5-6 mg/day, divided into 4 doses. Lesser amounts, 3.6 mg/day decreased panic attacks but did not eliminate panic attacks. The extended release formula was effective at an average dose of 4.4 to 4.7 mg, once daily
- Clonazepam (Klonopin), at an average dose of 2.3 mg per day, with 1 mg being a starting point and increased as needed. Higher doses caused increased side effects.
- Diazepam, at an average dose of 30 mg/day, divided into two doses.
- Fluoxetine (Prozac) was effective at both 10 mg and 20 mg.
- Paroxetine (Paxil), one study showed effectiveness at 40 mg and other studies showed effectivenss at an average dose of 50 mg
- Sertraline (Zoloft), at average doses of between 118 mg and 126 mg with some studies showing results at doses as low as 50 mg.
- Citalopram (Celexa), at an average of 20 mg to 30 mg
- Escitalopram (Lexapro), at an average dose of 11 mg.
- Venlafaxine ER (Effexor), an effective starting point is 75 mg with remission from panic attacks at an average of 163 mg
"Medication Dosing in Anxiety Disorders: What the Evidence Shows," 2009, Matthew P. White, MD, MS, Primary Psychiatry, Vol 16(10), pp 21-28