In <2ntudn$155b at inca.gate.net> odin at gate.net () writes:
>Can someone tell me what it is exactly that baclofen does? Is it a
>relaxant or does it affect the firing of the synapses much like tegretol?
>I recently had it prescribed for tic deleroux in lieu of dillantin to be
>taken along with tegretol [which seems to be effective] and I would like
>to know how baclofen is expected to work with the tegretol?
Mechanism of action/Effect: The precise mechanism of
action of baclofen has not been fully determined. It acts
mainly at the spinal cord level to inhibit the transmission
of both monosynaptic and polysynaptic reflexes, possibly by
hyperpolarization of primary afferent fiber terminals
resulting in antagonism of the release of putative
excitatory transmitters (i.e., glutamic and aspartic acids).
Actions at supraspinal sites may also be involved.
Other actions/effects: Baclofen has general central
nervous system (CNS)-depressant actions.
Absorption: Rapid and extensive but subject to
interpatient variation. Also, the rate and extent of
absorption may decrease with increasing doses.
Protein binding: Low.
Biotransformation: Hepatic; only about 15% of a dose
Half-life: 2.5 to 4 hours.
Onset of action: Highly variable; may range from
hours to weeks.
Time to peak concentration: 2 to 3 hours.
Peak serum concentration: 500 to 600 nanograms per
mL (ng/mL) (2.34 to 2.81 micromoles/L) following a 40-mg
single dose; concentration remains above 200 ng/mL (0.94
micromoles/L) for 8 hours.
Therapeutic serum concentration: 80 to 400 ng/mL
(0.37 to 1.87 micromoles/L).
Elimination: Renal; 70 to 85% of a dose is excreted
unchanged within 24 hours. Small amounts may also be
excreted via the feces. About 40% of a dose is usually
excreted within 6 hours, and excretion is usually complete
within 3 days; however, with chronic use the rate of
excretion is subject to interpatient variation.
(From US Pharmacopea)
Wayne Phillips wayne at phillips.boulder.co.us
Boulder PTSD Center, Boulder, CO (303)440-4599