Alzheimer's Disease & Dementia Drug Summary

Last updated: 21 January 2025

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Dosage Guidelines

Content on this page:

Dosage Guidelines

Dosage Guidelines


ANTI-AMYLOID MONOCLONAL ANTIBODY1
Drug Dosage Remarks
Aducanumab (Aducanumab-avwa) Initial dose:
Infusion 1 and 2: 1 mg/kg IV infusion every 4 weeks
Infusion 3 and 4: 3 mg/kg IV infusion ever 4 weeks
Infusion 5 and 6: 6 mg/kg IV infusion every 4 weeks
Maintenance dose:
Infusion 7 onwards: 10 mg/kg IV infusion every 4 weeks		 Adverse Reactions
  • Amyloid related imaging abnormalities (ARIA) with edema (ARIA-E), which can be sulcal effusion or brain edema, and hemosiderin deposition (ARIA-H), which includes microhemorrhages and superficial siderosis
  • Other effects (headache, diarrhea, angioedema, urticaria)

Special Instructions

  • IV infusions must be administered over approximately 1 hour
  • ARIA can occur at any time after treatment
Lecanemab (Lecanemab-irmb) 10 mg/kg IV every 2 weeks Adverse Reactions
  • CNS effects (headache, brain edema, ARIA including sulcal effusion, cerebral hemorrhage, microhemorrhage, superficial siderosis); Other effects (diarrhea, atrial fibrillation, lymphocytopenia, cough)
  • Infusion-related reactions have been observed (eg fever, flu-like symptoms, nausea and vomiting, hypotension or hypertension, oxygen desaturation, hypersensitivity)
Special Instructions  
  • Use with caution when considering concomitant therapy with antithrombotics or thrombolytic agents
  • Use with caution in patients at risk of having intracerebral hemorrhage
1United States Food and Drug Administration (US FDA) approved via the Accelerated Approval pathway for the treatment of early AD. The administration should be properly guided by the Appropriate Use Recommendations (AURs) in clinical practice.




ATYPICAL/2ND GENERATION ANTIPSYCHOTIC
Drug Dosage Remarks
Other Antipsychotic
Brexpiprazole Treatment of agitation associated with dementia due to AD:
Initial dose:
Day 1-7: 0.5 mg PO 24 hourly
Day 8-14: 1 mg PO 24 hourly
Day 15 onwards: 2 mg PO 24 hourly
Target dose: 2 mg PO 24 hourly
May increase to 3 mg PO 24 hourly after at least 2 weeks
Max dose: 3 mg/day		 Adverse Reactions
  • Psychiatric effects (suicidal thoughts/behavior, agitation, compulsive disorders); CNS effects (insomnia, anxiety, headache, lightheadedness, drowsiness, sedation, tremor); GI effects (constipation, nausea and vomiting); CV effects (tachycardia, orthostatic hypotension); Endocrine effect (hyperprolactinemia); Other effects (weight gain, dyslipidemia, blurred vision, fatigue)
  • Potentially fatal: Neuroleptic malignant syndrome (NMS), blood dyscrasias, ketoacidosis/hyeperosmolar coma
  • Incidence of extrapyramidal symptoms is low with akathisia being the most commonly reported; tardive dyskinesia is infrequent
Special Instructions
  • Use with caution in patients with known CV disease, cerebrovascular disease, Parkinson's disease or diseases that would predispose patients to hypotension, patients with a history of seizure, dementia-related psychosis
  • Use with caution in patients taking strong CYP34A or CYP2D6 inhibitors and inducers
  • CBC, fasting lipid profile, and fasting blood glucose/HbA1c should be tested prior to therapy then monitored periodically
  • Perform annual eye examination
  • Monitor for suicidal ideation or clinical worsening
  • Avoid abrupt withdrawal



CHOLINESTERASE INHIBITORS (ORAL)
Drug Dosage Remarks
Donepezil Initial dose: 5 mg PO 24 hourly
May increase to 10 mg PO 24 hourly at bedtime after 4-6 weeks, if tolerated
Max dose: 10 mg/day
or
23 mg PO 24 hourly at bedtime in patients with moderate-severe dementia who have been established on 10 mg 24 hourly for at least 3 months

 Adverse Reactions
  • GI effects (nausea and vomiting, diarrhea, anorexia, abdominal pain, dyspepsia); CNS effects (headache, insomnia, tremor, dizziness); Other effects (fatigue, muscle cramps)
  • Rarely, angina, bradycardia, GI hemorrhage, seizures; increased liver transaminases have been noted

Special Instructions

  • Use with caution in patients with supraventricular cardiac conduction abnormalities, patients with seizures, chronic obstructive disease (COPD), asthma, risk of GI bleeding, or in patients with GI or bladder outlet obstruction
  • Use is not recommended in patients recovering from bladder or GI surgery
Galantamine Initial dose: 4 mg PO 12 hourly for 4 weeks
Maintenance dose: 8 mg PO 12 hourly for ≥4 weeks
Max dose: 24 mg/day
Moderate hepatic impairment: 4 mg PO 24 hourly for 1 week
May increase to 4 mg PO 12 hourly for ≥4 weeks
Max dose: 16 mg/day
Extended-release:
Initial dose: 8 mg/day
Maintenance dose: 16 mg/day for ≥4 weeks
Moderate hepatic impairment: 8 mg PO 24 hourly every other day for 1 week
May increase to 8 mg PO 24 hourly for 4 weeks
Max dose: 16 mg/day		 Adverse Reactions
  • GI effects (nausea and vomiting, diarrhea, anorexia, abdominal pain, dyspepsia); CNS effects (headache, insomnia, tremor, dizziness); Other effects (fatigue, muscle cramps)
  • Rarely angina, bradycardia, GI hemorrhage, seizures; increased liver transaminases have been noted
Special Instructions  
  • Take doses with breakfast and dinner
  • Ensure adequate fluid intake during treatment
  • If medication is missed for ≥3 days, restart at lowest dose and increase to current dose
  • Treatment should be maintained at maximum tolerated dose
  • Avoid in patients with severe renal or hepatic impairment
  • Use with caution in patients with supraventricular cardiac conduction abnormalities, patients with seizures, COPD, asthma, risk of GI bleeding or in patients with bladder outlet obstruction
  • No dosage adjustment is needed in patients with mild liver and renal impairment
 Rivastigmine Initial dose: 1.5 mg PO 12 hourly 
If tolerated, may increase dose to 3 mg PO 12 hourly at intervals of ≥2 weeks, then to 4.5 mg PO 12 hourly, up to max dose of 6 mg 12 hourly 

 Adverse Reactions

  • GI effects (nausea and vomiting, diarrhea, anorexia, abdominal pain, dyspepsia); CNS effects (headache, insomnia, tremor, dizziness); Other effects (fatigue, muscle cramps)
  • Rarely angina, bradycardia, GI hemorrhage, seizures; increased liver transaminases have been noted

Special Instructions

  • Take doses with breakfast and dinner
  • If medication is missed for several days, restart at lowest dose and increase to current dose
  • Treatment should be maintained at maximum tolerated dose
  • Avoid in patients with severe hepatic impairment
  • Use with caution in patients with sick sinus syndrome or other cardiac conduction abnormalities (atrioventricular block), history of seizures, history of asthma or other obstructive lung diseases, risk of gastric ulcer, patients with urinary obstruction




CHOLINESTERASE INHIBITOR (TRANSDERMAL)
Drug Available Strength  Dosage Remarks
Rivastigmine 5 cm2 patch contains 9 mg Rivastigmine which delivers 4.6 mg/24 hours
10 cm2 patch contains 18 mg Rivastigmine which delivers 9.5 mg/24 hours
15 cm2 patch contains 27 mg Rivastigmine which delivers 13.3 mg/24 hours		 Initial dose: Apply 4.6 mg/24 hours patch once daily 
After a minimum of 4 weeks and if tolerated, may increase to 9.5 mg/24 hours patch
Max dose: 13.3 mg/24 hours patch for moderate to severe dementia
 Adverse Reactions
  • The following effects are associated with higher-than-recommended dose: CNS effects (headache, confusion, dizziness, agitation, depression, insomnia, tremor); GI effects (abdominal pain, diarrhea, dyspepsia, nausea and vomiting, anorexia); Other effects (sweating, malaise, fatigue, asthenia)
  • Rarely angina, gastric and duodenal ulcers, seizures, rashes

Special Instructions

  • Apply to upper back, lower back, upper arm or chest; area should be clean, dry, and hairless with intact skin
  • Avoid applying a new patch to the same spot for at least 14 days
  • Use with caution in patients with sick sinus syndrome or other cardiac conduction abnormalities (atrioventricular block), history of seizures, asthma, or other obstructive lung diseases, risk of gastric ulcer disease, or in patients with urinary obstruction
  • Clinical benefit should be reassured on a regular basis and discontinuation should be considered when evidence of a therapeutic effect at the optimal dose is no longer present
  • If the treatment is missed once, apply a new patch immediately. If treatment is missed for several days, restart with 4.6 mg/24 hours and titrate to the next dose after 4 weeks




N-METHYL-D-ASPARTATE (NMDA)-RECEPTOR ANTAGONIST
Drug Dosage Remarks
Memantine 1st wk: 5 mg/day PO
2nd wk: 10 mg/day PO
3rd wk: 15 mg/day PO
4th wk and thereafter: 20 mg/day PO
Max dose: 20 mg/day PO
Moderate renal impairment: 10 mg/day PO		 Adverse Reactions
  • GI effects (constipation, vomiting); CNS effects (headache, somnolence, dizziness, anxiety, hallucinations, confusion); CV effects (hypertension, thromboembolism); Other effects (cystitis, fungal infections)

Special Instructions

  • Avoid with other NMDA antagonists (eg Amantadine, Dextromethorphan, Ketamine)
  • Use with caution in patients with severe renal dysfunction, epilepsy, recent myocardial infarction, uncontrolled hypertension, uncompensated congestive heart failure, conditions that raise urine pH




OTHER AGENTS USED TO TREAT COGNITIVE SYMPTOMS
Drug Dosage Remarks
Monoamine Oxidase B Inhibitor
Selegiline 5-10 mg PO 24 hourly Adverse Reactions
  • CV effects (postural hypotension, chest pain); CNS effects (headache, tremor, dizziness, depression, hallucinations, agitation); GI effects (nausea and vomiting, constipation, diarrhea, dry mouth); Other effects (sore throat, muscle cramps)
Special Instructions
  • Avoid in patients with active GI bleeding
  • Use with caution in patients with history of GI ulcer, uncontrolled hypertension, arrhythmias, angina, psychosis, severe hepatic or renal impairment
 Nootropics and Neurotonics/Neurotrophics
Choline alfoscerate 400 mg PO 8-12 hourly

Adverse Reactions

  • GI effects (nausea, gastritis, GI disease); CNS effects (drowsiness, insomnia, antagonism, nervousness, convulsion, hyperkinesia)

Special Instructions

  • Contraindicated in women with childbearing potential, pregnant or lactating
 Citicoline 
 500 mg PO 12-24 hourly or 
1,000 mg PO 24 hourly

Adverse Reactions

  • Occasionally, may stimulate parasympathetic effects, fleeting and discrete hypotensor effect

Special Instructions

  • Contraindicated in patients with parasympathetic hypertonia
 Peptide (Cerebrolysin concentrate) (Porcine brain-derived peptide) 10-50 mL IV infusion (in normal saline solution [NSS], Ringer's solution, 5% glucose solution, dextram 40) 24 hourly for 2-4 weeks
or 
Up to 5 mL IM or up to 10 mL IV 24 hourly for 2-4 weeks

Adverse Reactions

  • Hypersensitivity reactions

Special Instructions

  • Contraindicated in patients with severe renal impairment, status epilepticus, grand mal fits
 Piracetam 1.2-4.8 g/day PO in 2-4 divided doses
Treatment may be initiated at 4.8 mg/day PO in 2-4 divided doses depending on the severity of symptoms

Adverse Reactions

  • CNS effects (insomnia, somnolence, hyperkinesia, nervousness, depression); GI effects (abdominal pain, nausea and vomiting, diarrhea); Other effects (weight gain, rashes)

Special Instructions

  • Avoid in patients with hepatic or severe renal impairment
  • Do not discontinue abruptly
 Peripheral Vasodilators and Cerebral Activators
 Gingko biloba (EGb 761) 120-240 mg/day PO divided 12-24 hourly

Adverse Reactions

  • CNS effects (headache, dizziness); GI effects (nausea, dyspepsia); Other effects (palpitations, bleeding disorders and skin hypersensitivity reactions)

Special Instructions

  • May be taken with or without food
  • Use with caution in patients with seizure disorders, patients receiving anticoagulants or drugs that affect platelet aggregation, those with clotting disorders or at risk for bleeding
    • However, studies have supported that EGb 761 is safe with Aspirin, Ticlopidine, Rivaroxaban, and Warfarin
 Nicergoline 10 mg PO 8 hourly or 30 mg PO 12-24 hourly

Adverse Reactions

  • GI effects (nausea, diarrhea, hyperacidity); CV effect (hypotension, especially after parenteral administration); CNS effects (dizziness, somnolence, insomnia, headache); Other effects (hot flushes, malaise)

Special Instructions

  • Should be taken on an empty stomach
  • Use with caution in porphyria, in patients with hyperuricemia or with a history of gout and/or under treatment with drugs that interfere with uric acid metabolism
  • May potentiate effects of antihypertensive drugs
 Enteral Nutritional Products
 Docosahexanoic acid (DHA)/Eicosapentanoic acid (EPA)/Uridine monophosphate (UMP)/Choline/Vitamin B6, B12/Vitamin C/Vitamin E/Folic acid/Phospholipids/Selenium 125 mL PO 24 hourly
Special Instructions
  • For enteral use only
  • Avoid use in patients with galactosemia
  • Use with caution in patients with allergy to milk, fish, and soy




SUPPLEMENTS AND ADJUVANT THERAPY
Drug Dosage Remarks
Neuropeptides, amino acids as peptones (from porcine brain proteins) 1 cap PO 24 hourly

Special Instructions

  • Should be taken in the morning
  • Not suitable in patients with lactose intolerance

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