Which drug is not used in Alzheimer Disease ?

Ropinirole is an antiparkinsonian drug, while the rest of them are drugs for Alzheimer disease.The management of AD is challenging and gratifying despite the absence of a cure or a robust pharmacologic treatment. Donepezil (target dose, 10 mg daily), rivastigmine (target dose, 6 mg twice daily or 9.5-mg patch daily), galantamine (target dose 24 mg daily, extended-release), and memantine (target dose, 10 mg twice daily) are approved by the Food and Drug Administration (FDA) for the treatment of AD. Due to hepatotoxicity, tacrine is no longer used. Reference: Harrison's Principles of Internal Medicine; 19th edition; Chapter 448 Alzheimer's Disease and Other Dementias