Memantine

Memantine hydrochloride tablets are indicated for the treatment of moderate to severe dementia of the Alzheimer’s type. Memantine hydrochloride tablets are an N-methyl-D-aspartate (NMDA) receptor antagonist indicated for the treatment of moderate to severe dementia of the Alzheimer’s type. (1)

• The recommended starting dose of memantine hydrochloride tablets is 5 mg once daily
• The dose should be increased in 5 mg increments to 10 mg/day (5 mg twice daily), 15 mg/day (5 mg and 10 mg as separate doses), and 20 mg/day (10 mg twice daily)
• The minimum recommended interval between dose increases is one week
• The dosage shown to be effective in controlled clinical trials is 20 mg/day
• Memantine hydrochloride tablets can be taken with or without food
• If a patient misses a single dose of memantine hydrochloride tablets, that patient should not double up on the next dose
• The next dose should be taken as scheduled
• If a patient fails to take memantine hydrochloride tablets for several days, dosing may need to be resumed at lower doses and retitrated as described above
• Specific Populations Renal Impairment A target dose of 5 mg twice daily is recommended in patients with severe renal impairment (creatinine clearance of 5 to 29 mL/min based on the Cockcroft-Gault equation)
• Hepatic Impairment Memantine hydrochloride tablets should be administered with caution to patients with severe hepatic impairment [see Clinical Pharmacology ]
• May be taken with or without food
• Initial dose is 5 mg once daily
• Increase dose in 5 mg increments to a maintenance dose of 10 mg twice daily
• A minimum of 1 week of treatment with the previous dose should be observed before increasing the dose

Memantine Hydrochloride Tablet USP, 5 mg: orange colored, oblong, biconvex, film-coated tablets debossed “IP 173” on one side and plain on the other side. Memantine Hydrochloride Tablet USP, 10 mg: gray colored, oblong, biconvex, film-coated tablets debossed “IP 174” on one side and plain on the other side. Tablets: 5 mg and 10 mg (3)

• Safety and effectiveness
• In pediatric patients have not been established
• Memantine failed to demonstrate efficacy in two 12-week controlled clinical studies of 578
• Pediatric patients aged 6 to 12 years with autism spectrum disorders (ASD), including autism, Asperger’s disorder and Pervasive Development Disorder - Not Otherwise Specified (PDD-NOS)
• Memantine has not been studied
• In pediatric patients under 6 years of age or over 12 years of age
• Memantine treatment was initiated at 3 mg/day and the dose was escalated to the target dose (weight-based) by week 6. …

The majority of people with Alzheimer’s disease are 65 years and older. In the clinical studies of memantine hydrochloride the mean age of patients was approximately 76; over 90% of patients were 65 years and older, 60% were 75 years and older, and 12% were at or above 85 years of age. The efficacy and safety data presented in the clinical trial sections were obtained from these patients. …

• See FDA-approved patient labeling (Patient Information)
• To assure safe and effective use of memantine hydrochloride, the following information and instructions provided in the patient information section should be discussed with patients and caregivers
• Patients/caregivers should be instructed to follow the dose titration schedule provided by their physician or healthcare professional for memantine hydrochloride
• They should be warned not to use any tablets of memantine hydrochloride that are damaged or show signs of tampering
• If a patient misses a single dose of memantine hydrochloride, that patient should not double up on the next dose
• The next dose should be taken as scheduled. …

• Memantine hydrochloride tablets are contraindicated in patients with known hypersensitivity to memantine hydrochloride or to any excipients used in the formulation
• Memantine hydrochloride tablets are contraindicated in patients with known hypersensitivity to memantine hydrochloride or to any excipients used in the formulation

7.1 Drugs that Make the Urine Alkaline The clearance of memantine was reduced by about 80% under alkaline urine conditions at pH 8. Therefore, alterations of urine pH towards the alkaline condition may lead to an accumulation of the drug with a possible increase in adverse effects. Urine pH is altered by diet, drugs (e.g. carbonic anhydrase inhibitors, sodium bicarbonate) and clinical state of the patient (e.g. renal tubular acidosis or severe infections of the urinary tract). Hence, memantine should be used with caution under these conditions. …

Conditions that raise urine pH may decrease the urinary elimination of memantine, resulting in increased plasma levels of memantine. (5.1, 7.1) 5.1 Genitourinary Conditions Conditions that raise urine pH may decrease the urinary elimination of memantine resulting in increased plasma levels of memantine [see Drug Interactions (7.1) ] .

Most common adverse reactions (≥ 5 % and greater than placebo) are dizziness, headache, confusion and constipation. (6.1) To report SUSPECTED ADVERSE REACTIONS, contact Amneal Pharmaceuticals at 1-877-835-5472 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Memantine hydrochloride was evaluated in eight double-blind placebo-controlled trials involving a total of 1862 dementia (Alzheimer’s disease, vascular dementia) patients (940 patients treated with memantine hydrochloride and 922 patients treated with placebo) for a treatment period up to 28 weeks. …

8.1 Pregnancy Risk Summary There are no adequate data on the developmental risk associated with the use of memantine hydrochloride in pregnant women. Adverse developmental effects (decreased body weight, and skeletal ossification) were observed in the offspring of rats administered memantine during pregnancy at doses associated with minimal maternal toxicity. …

Signs and symptoms most often accompanying memantine overdosage in clinical trials and from worldwide marketing experience, alone or in combination with other drugs and/or alcohol, include agitation, asthenia, bradycardia, confusion, coma, dizziness, ECG changes, increased blood pressure, lethargy, loss of consciousness, psychosis, restlessness, slowed movement, somnolence, stupor, unsteady gait, visual hallucinations, vertigo, vomiting, and weakness. …

Tome assim que lembrar, a menos que esteja quase na hora da próxima dose. Nesse caso, pule a dose esquecida. Nunca tome duas doses de uma vez para compensar. Confira a bula, pois alguns medicamentos são diferentes.