Steady state indtræder 7- 14 dage efter behandlingens start med standard eller controlled release formuleringer, og de farmakokinetiske egenskaber lader ikke til at ændre sig under langtidsbehandling.
Steady state systemic levels are attained by 7 to 14 days after starting treatment with immediate or controlled release formulations and pharmacokinetics do not appear to change during long-term therapy.