Dementia is a syndrome, not a disease. Dementia is a group of symptoms that affects mental cognitive tasks such as memory and reasoning. Dementia is an umbrella term that Alzheimer's disease can fall under. It can occur due to a variety of conditions, the most common of which is Alzheimer's disease
It's important to discuss all of the drugs you take with your doctor and understand their desired effects and possible side effects. Never stop taking a medication and never change your dose or frequency without first consulting your doctor