Posted by ed_uk on January 14, 2005, at 16:27:09
To all stimulant users...
What dosage regimen do you find to be the most effective and tolerable???
How many hours per day do you attempt to 'cover' by use of the stimulant? eg. 12h, 16h etc.
Do you find that the efficacy of your stimulant decreases throughout the day?
Do you suffer from insomnia?
About methylphenidate (Ritalin)....
'In addition to the morning and noon doses commonly used in hyperactivity disorders, studies have shown improved clinical outcome with little adverse effect on sleep patterns if a third late afternoon dose is given.'
But acute tolerance may be a problem if stimulants are used to 'cover' a larger fraction of the day........
Clin Pharmacol Ther. 1999 Sep;66(3):295-305.
Acute tolerance to methylphenidate in the treatment of attention deficit hyperactivity disorder in children.
OBJECTIVES: To evaluate the efficacy of several drug delivery patterns of methylphenidate and to determine whether acute tolerance develops to this widely used stimulant medication in the treatment of children with attention deficit hyperactivity disorder. METHODS: Double-blind trials were conducted in a laboratory school setting in which multiple measures of efficacy were obtained frequently in the morning and afternoon across the school day. In study I, relative efficacy was determined for three dosing patterns of methylphenidate: a standard twice-daily profile, a flat profile, and an ascending profile. In study II, tolerance was assessed by comparison of three-times-a-day regimens in which the time of the middle dose varied. RESULTS: In study I, the efficacy of the ascending treatment increased across the day, and in the afternoon it was equal to the efficacy of the twice-daily treatment, indicating that an initial bolus was not required for efficacy. The efficacy of the flat treatment declined across the day, and in the afternoon it was significantly less than in the twice-daily treatment, suggesting that tolerance may be developing. In study II, acute improvements in efficacy were reduced to the second of two closely spaced but not to two widely spaced bolus doses, suggesting that shortly after exposure to high concentrations, efficacy is reduced to given concentrations of methylphenidate. In a concentration-effect model, a tolerance term was needed to account for counterclockwise hysteresis. CONCLUSIONS: Acute tolerance to methylphenidate appears to exist. This should be considered in the design of an optimal dosing regimen for the treatment of children with attention deficit hyperactivity disorder.
poster:ed_uk
thread:442219
URL: http://www.dr-bob.org/babble/20050113/msgs/442219.html