Memantine oral
- Drugs List
- Therapeutic Indications
- Dosage
- Contraindications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
- Monograph
Presentation
Oral formulations of memantine hydrochloride.
Drugs List
Therapeutic Indications
Uses
Moderate to severe Alzheimer's disease
Dosage
Adults
The maximum daily dose is 20mg per day. In order to reduce the risk of side effects the maintenance dose is achieved by upward titration of 5mg per week over the first 3 weeks as follows:
Treatment should be started with 5mg daily (0.5ml equivalent to one pump actuation of oral solution) during the first week.
In the second week 10mg daily (1ml equivalent to two pump actuations of oral solution) is recommended.
In the third week 15mg daily (1.5ml equivalent to three pump actuations of oral solution) is recommended.
From the fourth week on, treatment can be continued with the recommended maintenance dose of 20mg daily (2ml equivalent to four pump actuations of oral solution).
Patients with Renal Impairment
Creatinine clearance 30 to 49ml/minute
10mg a day (1ml equivalent to two pump actuations of oral solution). After at least 7 days, if the dose is well tolerated, it can be titrated up to 20mg a day (2ml equivalent to four pump actuations of oral solution).
Creatinine clearance 5 to 29ml/minute
10mg a day (1ml equivalent to two pump actuations of oral solution).
Additional Dosage Information
0.5ml (equivalent to one pump actuation) oral solution contains 5mg memantine hydrochloride.
Contraindications
Children under 18 years
Breastfeeding
Renal impairment - creatinine clearance below 5ml/minute
Severe hepatic impairment
Precautions and Warnings
Predisposition to epileptic disorder
Restricted sodium intake
Epileptic disorder
Galactosaemia
Glucose-galactose malabsorption syndrome
Hereditary fructose intolerance
History of seizures
Lactose intolerance
Phenylketonuria
Pregnancy
Recent myocardial infarction
Renal impairment - creatinine clearance 5-49 ml/minute
Renal tubular acidosis
Severe decompensated cardiac failure
Uncontrolled hypertension
Urinary tract infection
Reduce dose in patients with creatinine clearance 5-29ml/minute
Reduce dose initially in patients with creatinine clearance 30-49 ml/min
Sodium content of effervescent preparation may be significant
Some formulations contain aspartame - caution in phenylketonuria
Advise ability to drive/operate machinery may be affected by side effects
Do not start treatment unless a carer is available to monitor drug intake
Treatment to be initiated and supervised by a specialist
Presentations with sorbitol unsuitable in hereditary fructose intolerance
Some formulations contain lactose
Assess benefit within 3 months and evaluate continued need regularly
Assess patient's tolerance to treatment
Monitor patients with elevated urine pH
Monitor prothrombin times closely in patients on anticoagulant therapy
Discontinue if therapeutic effect is no longer present
Some factors which may raise urine pH may necessitate careful monitoring of the patient. These factors include drastic changes in diet, e.g. from a carnivorous to a vegetarian diet, or a massive ingestion of alkalising gastric buffers. Also, urine pH may be elevated by states of renal tubular acidosis (RTA) or severe infections of the urinary tract with Proteus bacteria.
Pregnancy and Lactation
Pregnancy
Use memantine with caution in pregnancy.
The manufacturer does not recommend use of memantine during pregnancy unless clearly necessary. At the time of writing, there is limited published information regarding the use of memantine during pregnancy.
Animal studies indicate a potential for reducing intrauterine growth at exposure levels which are identical or slightly higher than at human exposure. Memantine was not found to be teratogenic in rats and rabbits at maternally toxic doses. The potential risk for humans is unknown.
Lactation
Memantine is contraindicated in breastfeeding.
It is not known whether memantine is excreted in human breast milk. At the time of writing there is limited published information regarding the use of memantine during breastfeeding. It is likely memantine is excreted into breast milk due to the lipophilicity.
Counselling
Advise patient that memantine should be taken once a day, at the same time each day.
Advise patient that the oral drop solution should be discarded three months after first opening.
Advise outpatients to take special care as moderate to severe Alzheimer's disease usually causes impairment of driving performance and compromises the ability to use machinery. Furthermore, memantine has minor or moderate influence on the ability to drive and operate machinery.
Side Effects
Altered liver function tests
Cardiac failure
Confusion
Constipation
Depression
Dizziness
Dyspnoea
Fatigue
Fungal infection
Gait abnormality
Hallucinations
Headache
Hepatitis
Hypersensitivity reactions
Hypertension
Loss of balance
Pancreatitis
Psychotic reactions
Seizures
Somnolence
Suicidal tendencies
Thromboembolism
Venous thrombosis
Vomiting
Overdosage
It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.
The following number will direct the caller to the relevant local centre (0844) 892 0111
Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Further Information
Last Full Review Date: April 2018
Reference Sources
Summary of Product Characteristics: Alzhok 10mg Soluble Tablets. Glenmark Pharmaceuticals Europe Limited. Revised December 2016.
Summary of Product Characteristics: Alzhok 20mg Soluble Tablets. Glenmark Pharmaceuticals Europe Limited. Revised December 2016.
Summary of Product Characteristics: Alzhok 5mg+10mg+15mg+20mg Soluble Tablets. Glenmark Pharmaceuticals Europe Limited. Revised January 2018.
Summary of Product Characteristics: Ebixa 5mg/pump actuation oral solution, 20mg and 10mg tablets and treatment initiation pack. Lundbeck Ltd. Revised October 2016.
Summary of Product Characteristics: Memantine 10mg soluble tablets. Zentiva. Revised July 2021.
Summary of Product Characteristics: Memantine 20mg soluble tablets. Zentiva. Revised July 2021.
Summary of Product Characteristics: Nemdatine 10mg tablets. Actavis UK Ltd. Revised July 2015.
Summary of Product Characteristics: Nemdatine 20mg tablets. Actavis UK Ltd. Revised July 2016.
Summary of Product Characteristics: Nemdatine tablets treatment initiation pack. Actavis UK Ltd. Revised July 2015.
Summary of Product Characteristics: Valios 10mg and 20mg orodispersible tablets. Dr Reddys Laboratories (UK) Ltd. Revised July 2015.
Summary of Product Characteristics: Valios 5mg/ 10mg/15mg/20mg orodispersible tablets (initiation pack). Dr Reddys Laboratories (UK) Ltd. Revised July 2015.
NICE Evidence Services Available at: www.nice.org.uk Last accessed: 17 January 2022
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