Lamictal or trileptal more sedating
Long-acting forms such as Carbatrol or Tegretol-XR can be given once a day.
The effectiveness criticism probably is because it is often prescribed at too low a dose.
The drug probably works by influencing transport of GABA and effects on calcium channels.
Typical adult dose is 300-600 mg three times a, but doses can be up to 1200 mg three times a day.
I often start at 300 mg per day, sometimes in one dose or with 100 mg pills, and increase over a month or two to the full dose.
Benzodiazepines are used as anti-seizure drugs, sedatives, tranquilizers and muscle relaxants.