Pharmacokinetic profiles of current therapies for Alzheimer's disease: Implications for switching to galantamine

Although no pharmacologic treatments have been proved to alter the patholog y of Alzheimer's disease, acetylcholinesterase inhibitor (AChEI) therapy of fers symptomatic improvements in or delays in the progression of cognitive, behavioral, and functional deficits. Tacrine, donepezil, rivastigmine, and galantamine are the best studied agents in this class. These drugs have va rying pharmacokinetic, safety, and tolerability profiles that can affect pa tient outcomes. Specifically, certain metabolic parameters tie, half-life a nd route of metabolism/elimination) can affect a drug's tolerability and be come important when a switch from one agent to another is contemplated. The mechanism of action of galantamine, the most recently approved AChEI, vari es from that of the other AChEIs in that it has allosteric modulating activ ity at nicotinic receptors in addition to its ability to inhibit acetylchol inesterase. Benefits of this dual mode of action on the effects of the dise ase have been suggested.