Memantine and Donepezil Hydrochlorides

Memantine and donepezil hydrochlorides extended-release capsules are indicated for the treatment of moderate to severe dementia of the Alzheimer's type in patients stabilized on 10 mg of donepezil hydrochloride once daily. Memantine and donepezil hydrochlorides extended-release capsules are a combination of memantine hydrochloride, an NMDA receptor antagonist, and donepezil hydrochloride, an acetylcholinesterase inhibitor, indicated for the treatment of moderate to severe dementia of the Alzheimer’s type in patients stabilized on 10 mg of donepezil hydrochloride once daily. ( 1 )

Extended-Release Capsules:

• 21 mg memantine hydrochloride and 10 mg donepezil hydrochloride: hard gelatin capsules, with natural body and natural cap imprinted with the logo “A313” on the body and “21/10” on the cap in black ink, containing white to off-white beads Memantine and donepezil hydrochlorides extended-release capsules:
• 21 mg memantine hydrochloride and 10 mg donepezil hydrochloride ( 3 )

Memantine and donepezil hydrochlorides extended-release capsules are contraindicated in patients with known hypersensitivity to memantine hydrochloride, donepezil hydrochloride, piperidine derivatives, or to any excipients used in the formulation. Memantine and donepezil hydrochlorides extended-release capsules are contraindicated in patients with known hypersensitivity to memantine hydrochloride, donepezil hydrochloride, piperidine derivatives, or to any excipients used in the formulation. ( 4 )

• Memantine and donepezil hydrochlorides extended-release capsules are likely to exaggerate succinylcholine-type muscle relaxation during anesthesia. ( 5.1 )
• Memantine and donepezil hydrochlorides extended-release capsules may have vagotonic effects on the sinoatrial and atrioventricular nodes manifesting as bradycardia or heart block. ( 5.2 )
• Monitor patients for symptoms of active or occult gastrointestinal bleeding, especially those at increased risk for developing ulcers. ( 5.3 )
• Memantine and donepezil hydrochlorides extended-release capsules can cause diarrhea, nausea, and vomiting. ( 5.4 )
• Memantine and donepezil hydrochlorides extended-release capsules may cause bladder outflow obstructions. ( 5.5 )
• Conditions that raise urine pH may decrease the urinary elimination of memantine, resulting in increased plasma levels of memantine. ( 5.5 , 7.1 )

5.1 Anesthesia Donepezil hydrochloride, an active ingredient in memantine and donepezil hydrochlorides extended-release capsules, as a cholinesterase inhibitor, is likely to exaggerate succinylcholine-type muscle relaxation during anesthesia.

5.2 Cardiovascular Conditions Because of their pharmacological action, cholinesterase inhibitors may have vagotonic effects on the sinoatrial and atrioventricular nodes. This effect may manifest as bradycardia or heart block in patients both with and without known underlying cardiac conduction abnormalities. Syncopal episodes have been reported in association with the use of donepezil hydrochloride, an active ingredient in memantine and donepezil hydrochlorides extended-release capsules.

5.3 Peptic Ulcer Disease and Gastrointestinal Bleeding Through their primary action, cholinesterase inhibitors may be expected to increase gastric acid secretion due to increased cholinergic activity. Clinical studies of donepezil hydrochloride in a dose of 5 mg/day to 10 mg/day have shown no increase, relative to placebo, in the incidence of either peptic ulcer disease or gastrointestinal bleeding. Patients treated with memantine and donepezil hydrochlorides extended-release capsules should be monitored closely for symptoms of active or occult gastrointestinal bleeding, especially those at increased risk for developing ulcers, e.g., those with a history of ulcer disease or those receiving concurrent nonsteroidal anti-inflammatory drugs (NSAIDs).

5.4 Nausea and Vomiting Donepezil hydrochloride, an active ingredient in memantine and donepezil hydrochlorides extended-release capsules, when initiated, as a predictable consequence of its pharmacological properties, has been shown to produce diarrhea, nausea, and vomiting. Although in most cases, these effects have been mild and transient, sometimes lasting one to three weeks, and have resolved during continued use of donepezil hydrochloride, patients should be observed closely at the initiation of treatment.

5.5 Genitourinary Conditions Although not observed in clinical trials of donepezil hydrochloride, an active ingredient in memantine and donepezil hydrochlorides extended-release capsules, cholinomimetics may cause bladder outflow obstruction. Conditions that raise urine pH may decrease the urinary elimination of memantine, an active ingredient in memantine and donepezil hydrochlorides extended-release capsules, resulting in increased plasma levels of memantine [see Drug Interactions ( 7.1 )].

5.6 Seizures Cholinomimetics, including donepezil hydrochloride, an active ingredient in memantine and donepezil hydrochlorides extended-release capsules, are believed to have some potential to cause generalized convulsions. However, seizure activity also may be a manifestation of Alzheimer's disease.

5.7 Pulmonary Conditions Because of their cholinomimetic actions, cholinesterase inhibitors should be prescribed with care to patients with a history of asthma or obstructive pulmonary disease.

The following serious adverse reactions are discussed below and elsewhere in the labeling.

• Cardiovascular Conditions [see Warnings and Precautions ( 5.2 )]
• Peptic Ulcer Disease and Gastrointestinal Bleeding [see Warnings and Precautions ( 5.3 )]
• Nausea and Vomiting [see Warnings and Precautions ( 5.4 )]
• Genitourinary Conditions [ see Warnings and Precautions ( 5.5 )]
• Seizures [see Warnings and Precautions ( 5.6 )]
• Pulmonary Conditions [see Warnings and Precautions ( 5.7 )]
• The most common adverse reactions occurring at a frequency of at least 5% and greater than placebo with memantine hydrochloride extended-release 28 mg/day were headache, diarrhea, and dizziness. ( 6.1 )
• The most common adverse reactions occurring at a frequency of at least 5% in patients receiving donepezil hydrochloride and at twice or more the placebo rate, include diarrhea, anorexia, vomiting, nausea, and ecchymosis. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact ANI Pharmaceuticals, Inc. at 1-855-204-1431 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Memantine Hydrochloride Memantine hydrochloride extended-release was evaluated in a double-blind, placebo-controlled trial in 676 patients with moderate to severe dementia of the Alzheimer's type (341 patients treated with memantine 28 mg/day dose and 335 patients treated with placebo) for a treatment period up to 24 weeks. Of the patients randomized, 236 treated with memantine 28 mg/day and 227 treated with placebo were on a stable dose of donepezil for 3 months prior to screening. Adverse Reactions Leading to Discontinuation with Memantine Hydrochloride In the placebo-controlled clinical trial of memantine hydrochloride extended-release, the proportion of patients in the memantine hydrochloride extended-release 28 mg/day dose group and in the placebo group who discontinued treatment due to adverse reactions was 10% and 6%, respectively. The most common adverse reaction in the memantine hydrochloride extended-release treated group that led to treatment discontinuation was dizziness, at a rate of 1.5%. Most Common Adverse Reactions with Memantine Hydrochloride The most common adverse reactions with memantine hydrochloride extended-release in patients with moderate to severe Alzheimer's disease, defined as those occurring at a frequency of at least 5% in the memantine hydrochloride extended-release group and at a higher frequency than placebo, were headache, diarrhea, and dizziness. Table 1 lists adverse reactions that occurred at an incidence of ≥ 2% in the memantine hydrochloride extended-release treated group and occurred at a rate greater than placebo. Table 1: Adverse reactions with memantine hydrochloride extended-release in patients with moderate to severe Alzheimer's disease Adverse Reaction Placebo (n=335) % Memantine hydrochloride extended-release 28 mg (n=341) % Gastrointestinal Disorders Diarrhea 4 5 Constipation 1 3 Abdominal pain 1 2 Vomiting 1 2 Infections and Infestations Influenza 3 4 Investigations Increased weight 1 3 Musculoskeletal and Connective Tissue Disorders Back pain 1 3 Nervous System Disorders Headache 5 6 Dizziness 1 5 Somnolence 1 3 Psychiatric Disorders Anxiety 3 4 Depression 1 3 Aggression 1 2 Renal and Urinary Disorders Urinary incontinence 1 2 Vascular Disorders Hypertension 2 4 Hypotension 1 2 Donepezil hydrochloride Adverse Reactions Leading to Discontinuation with Donepezil Hydrochloride In controlled clinical trials of donepezil hydrochloride, the rate of discontinuation due to adverse reactions for patients treated with donepezil hydrochloride was approximately 12%, compared to 7% for patients treated with placebo. The most common adverse reactions leading to discontinuation, defined as those occurring in at least 2% of donepezil hydrochloride patients and at twice or more the incidence seen with placebo, were anorexia (2%), nausea (2%), diarrhea (2%) and urinary tract infection (2%). Most Common Adverse Reactions with Donepezil Hydrochloride The most common adverse reactions reported with donepezil hydrochloride in controlled clinical trials in patients with severe Alzheimer's disease, defined as those occurring at a frequency of at least 5% in the donepezil hydrochloride group and at twice or more the placebo rate, were diarrhea, anorexia, vomiting, nausea, and ecchymosis. The most common adverse reactions reported with donepezil hydrochloride in controlled clinical trials in patients with mild to moderate Alzheimer's disease were insomnia, muscle cramp, and fatigue. Table 2 lists adverse reactions that occurred at an incidence of ≥ 2% in the donepezil hydrochloride group and at a rate greater than placebo in controlled trials in patients with severe Alzheimer's disease. Table 2: Adverse reactions with donepezil hydrochloride in patients with severe Alzheimer’s disease Body System/Adverse Event Placebo (n=392) % Donepezil hydrochloride 10 mg/day (n=501) % Percent of Patients with any Adverse Event 73 81 Body as a Whole Accident 12 13 Infection 9 11 Headache 3 4 Pain 2 3 Back pain 2 3 Fever 1 2 Chest pain <1 2 Cardiovascular System Hypertension 2 3 Hemorrhage 1 2 Syncope 1 2 Digestive System Diarrhea 4 10 Vomiting 4 8 Anorexia 4 8 Nausea 2 6 Hemic and Lymphatic System Ecchymosis 2 5 Metabolic and Nutritional Systems Increased creatine phosphokinase 1 3 Dehydration 1 2 Hyperlipemia <1 2 Nervous System Insomnia 4 5 Hostility 2 3 Nervousness 2 3 Hallucinations 1 3 Somnolence 1 2 Dizziness 1 2 Depression 1 2 Confusion 1 2 Emotional lability 1 2 Personality disorder 1 2 Skin and Appendages Eczema 2 3 Urogenital System Urinary incontinence 1 2

6.2 Postmarketing Experience The following adverse reactions have been identified during post-approval use of memantine hydrochloride and donepezil hydrochloride. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Memantine Hydrochloride Acute renal failure, agranulocytosis, cardiac failure congestive, hepatitis, leukopenia (including neutropenia), pancreatitis, pancytopenia, Stevens Johnson Syndrome, suicidal ideation, thrombocytopenia, and thrombotic thrombocytopenic purpura. Donepezil Hydrochloride Abdominal pain, agitation, cholecystitis, confusion, convulsions, hallucinations, heart block (all types), hemolytic anemia, hepatitis, hyponatremia, neuroleptic malignant syndrome, pancreatitis, and rash.

• Combined use with NMDA antagonists: use with caution. ( 7.2 )
• Memantine and donepezil hydrochlorides extended-release capsules may interfere with anticholinergic medications. ( 7.4 )
• Concomitant administration of succinylcholine, similar neuromuscular blocking agents, or cholinergic agonists may lead to synergistic effect. ( 7.5 )

7.1 Use of Memantine with 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 reactions. 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.

7.2 Use of Memantine with Other N-methyl-D-aspartate (NMDA) Antagonists The combined use of memantine hydrochloride with other NMDA antagonists (amantadine, ketamine, and dextromethorphan) has not been systematically evaluated and such use should be approached with caution.

7.3 Effect of Other Drugs on the Metabolism of Donepezil Inhibitors of CYP3A4 (e.g., ketoconazole) and CYP2D6 (e.g., quinidine), inhibit donepezil metabolism in vitro. Whether there is a clinical effect of quinidine is not known. Inducers of CYP3A4 (e.g., phenytoin, carbamazepine, dexamethasone, rifampin, and phenobarbital) could increase the rate of elimination of donepezil.

7.4 Use of Donepezil with Anticholinergics Because of their mechanism of action, cholinesterase inhibitors, including donepezil hydrochloride, have the potential to interfere with the activity of anticholinergic medications.

7.5 Use of Donepezil with Cholinomimetics and Other Cholinesterase Inhibitors A synergistic effect may be expected when cholinesterase inhibitors, including donepezil hydrochloride, are given concurrently with succinylcholine, similar neuromuscular blocking agents, or cholinergic agonists such as bethanechol.

8.1 Pregnancy Risk Summary There are no adequate data on the developmental risk associated with the use of memantine and donepezil hydrochlorides extended-release capsules or its active ingredients (memantine hydrochloride and donepezil hydrochloride) in pregnant women. Adverse developmental effects (mortality and decreased body weight and skeletal ossification) were observed in the offspring of rats administered memantine or donepezil during pregnancy at doses associated with minimal maternal toxicity. These doses are higher than those used in humans at the recommended daily dose of memantine and donepezil hydrochlorides extended-release capsules [see Data] . In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. The background risk of major birth defects and miscarriage for the indicated population is unknown. Data Animal Data Memantine Hydrochloride Oral administration of memantine (2, 6, or 18 mg/kg/day) to rats during the period of organogenesis resulted in decreased skeletal ossification in fetuses at the highest dose tested. The higher no-effect dose for adverse developmental effects (6 mg/kg) is 2 times the dose of memantine at the recommended human daily dose (RHD) of memantine and donepezil hydrochlorides extended-release capsules (28 mg memantine/10 mg donepezil) on a body surface area (mg/m 2 ) basis. Oral administration of memantine to rabbits (3, 10, or 30 mg/kg/day) during the period of organogenesis resulted in no adverse developmental effects. The highest dose tested is approximately 20 times the dose of memantine at the RHD of memantine and donepezil hydrochlorides extended-release capsules on a mg/m 2 basis. In rats, memantine (2, 6, or 18 mg/kg/day) was administered orally prior to and throughout mating and, in females, through the period of organogenesis or continuing throughout lactation to weaning. Decreased skeletal ossification in fetuses and decreased body weight in pups were observed at the highest dose tested. The higher no-effect dose for adverse developmental effects (6 mg/kg/day) is 2 times the dose of memantine at the RHD of memantine and donepezil hydrochlorides extended-release capsules on a mg/m 2 basis. Oral administration of memantine (2, 6, or 18 mg/kg/day) to rats from late gestation throughout lactation to weaning, resulted in decreased pup weights at the highest dose tested. The higher no-effect dose (6 mg/kg/day) is approximately 2 times the dose of memantine at the RHD of memantine and donepezil hydrochlorides extended-release capsules on a mg/m 2 basis. Donepezil Hydrochloride Oral administration of donepezil to rats and rabbits during the period of organogenesis resulted in no adverse developmental effects. The highest doses (16 and 10 mg/kg/day, respectively) were approximately 15 and 7 times, respectively, the dose of donepezil at the RHD of memantine and donepezil hydrochlorides extended-release capsules on a mg/m 2 basis. Oral administration of donepezil (1, 3, or 10 mg/kg/day) to rats during late gestation and throughout lactation to weaning resulted in an increase in stillbirths and offspring mortality at the highest dose tested. The higher no-effect dose (3 mg/kg/day) is approximately 3 times the dose of donepezil at the RHD of memantine and donepezil hydrochlorides extended-release capsules on a mg/m 2 basis.

8.2 Lactation Risk Summary There are no data on the presence of memantine or donepezil in human milk, the effects on the breastfed infant, or the effects of memantine and donepezil hydrochlorides extended-release capsules or its metabolites on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for memantine and donepezil hydrochlorides extended-release capsules and any potential adverse effects on the breastfed infant from memantine and donepezil hydrochlorides extended-release capsules or from the underlying maternal condition.

8.4 Pediatric Use Safety and effectiveness of memantine and donepezil hydrochlorides extended-release capsules in pediatric patients have not been established. Memantine failed to demonstrate efficacy in two 12-week controlled clinical studies of 578 pediatric patients aged 6-12 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. Oral doses of memantine 3, 6, 9, or 15 mg extended-release capsules were administered once daily to patients with weights < 20 kg, 20-39 kg, 40-59 kg and ≥ 60 kg, respectively. In a randomized, 12-week double-blind, placebo-controlled parallel study (Study A) in patients with autism, there was no statistically significant difference in the Social Responsiveness Scale (SRS) total raw score between patients randomized to memantine (n=54) and those randomized to placebo (n=53). In a 12-week responder-enriched randomized withdrawal study (Study B) in 471 patients with ASD, there was no statistically significant difference in the loss of therapeutic response rates between patients randomized to remain on full-dose memantine (n=153) and those randomized to switch to placebo (n=158). The overall risk profile of memantine in pediatric patients was generally consistent with the known risk profile in adults [see Adverse Reactions ( 6.1 )]. In Study A, the adverse reactions in the memantine group (n=56) that were reported in at least 5% of patients and at least twice the frequency of the placebo group (N=58) are listed in Table 3: Table 3: Study A Commonly Reported Adverse Reactions with a Frequency ≥ 5% and Twice That of Placebo Adverse Reaction Memantine N=56 Placebo N=58 Cough 8.9% 3.4% Influenza 7.1% 3.4% Rhinorrhea 5.4% 0% Agitation 5.4% 1.7% Discontinuations due to adverse reactions a Aggression 3.6% 1.7% Irritability 1.8% 3.4% a Reported adverse reactions leading to discontinuation in more than one patient in either treatment group. The adverse reactions that were reported in at least 5% of patients in the 12-48 week open label study to identify responders to enroll in Study B are listed in Table 4: Table 4: 12-48 Week Open Label Lead-In study to Study B Commonly Reported Adverse Reactions with a Frequency ≥ 5% Adverse Reaction Memantine N=903 Headache 8.0% Nasopharyngitis 6.3% Pyrexia 5.8% Irritability 5.4% Discontinuations due to adverse reactions a Irritability 1.2% Aggression 1.0% a At least 1% incidence of adverse reactions leading to premature discontinuation In the randomized withdrawal study (Study B), the adverse reaction in patients randomized to placebo (n= 160) and reported in at least 5% of patients and at twice the frequency of the full-dose memantine treatment group (n=157) was irritability (5.0% vs 2.5%). In a juvenile animal study, male and female juvenile rats were administered memantine (15, 30, and 45 mg/kg/day) starting on postnatal day (PND) 14 through PND 70. Body weights were reduced at 45 mg/kg/day. Delays in sexual maturation were noted in male and female rats at doses ≥30 mg/kg/day. Memantine induced neuronal lesions in several areas of the brain on PND 15 and 17 at doses ≥30 mg/kg/day. Behavioral toxicity (decrease percent of auditory startle habituation) was noted for animals in the 45 mg/kg/day dose group. The 15 mg/kg/day dose was considered the No-Observed-Adverse-Effect-Level (NOAEL) for this study. In a second juvenile rat toxicity study, male and female juvenile rats were administered memantine (1, 3, 8, 15, 30, and 45 mg/kg/day) starting on postnatal day (PND) 7 through PND 70. Due to early memantine-related mortality, the 30 and 45 mg/kg/day dose groups were terminated without further evaluation. […]

Memantine and donepezil hydrochlorides extended-release capsules contain two approved medications: memantine hydrochloride and donepezil hydrochloride. Each of those medications is postulated to have a different mechanism in Alzheimer's disease. Memantine Persistent activation of central nervous system NMDA receptors by the excitatory amino acid glutamate has been hypothesized to contribute to the symptomatology of Alzheimer's disease. Memantine is postulated to exert its therapeutic effect through its action as a low to moderate affinity uncompetitive (open channel) NMDA receptor antagonist which binds preferentially to the NMDA receptor-operated cation channels. There is no evidence that memantine prevents or slows neurodegeneration in patients with Alzheimer's disease. Donepezil Current theories on the pathogenesis of the cognitive signs and symptoms of Alzheimer's disease attribute some of them to a deficiency of cholinergic neurotransmission. Donepezil is postulated to exert its therapeutic effect by enhancing cholinergic function. This is accomplished by increasing the concentration of acetylcholine in the central nervous system through reversible inhibition of its hydrolysis by acetylcholinesterase. There is no evidence that donepezil prevents or slows neurodegeneration in patients with Alzheimer's disease.