Memantine adverse effects

Low affinity use-dependent NMDA recqrtor antagonists meet the criteria for safe administration into patients. Drugs like amantadine and memantine have modest effects on Parkinson s disease and are used as initial therapy or as adjunct to l-DOPA. Their adverse effects include dizziness, lethargy and sleep disturbance. 

The site of action for Memantine is the central nervous system (CNS) and it has CNS affinity. Amantadine and Rimantadine can penetrate to the CNS and cause some adverse effects. 

Adverse reactions associated with memantine include constipation, confusion, dizziness, headache, coughing, and hypertension. These adverse effects are similar to those experienced with ChE inhibitors. Extra monitoring should be done if memantine is given concurrently with a ChE inhibitor. 

Memantine is approved for treatment of moderate to severe Alzheimer s disease. It is an antagonist at glutamatergic NMDA-receptors. Memantine is well tolerated and has a small beneficial effect at six months in moderate to severe AD (McShane et al. 2006). For patients with dementia one has to be careful wit all kind of medications that may affect the central nervous system. Delirium and hallucinations are common adverse effects in patients with dementia. Agitation may be due to delirium and external causes should be ruled out before adding another psychoactive drug. Sleep disturbance is common in demented elderly patients. Sleep deprivation may in a patient with dementia induce delirium. Nonpharmacological treatment for delirium or hallucinations should be considered first. 

Memantine is weii-toierated with a iow incidence of adverse effects... 

Memantine is an amantadine derivative that has been studied in patients with Parkinson s disease. Its adverse effects include agitation, restlessness, insomnia, pronounced delirious states, and muscular hypotonia. All were reversible after dosage reduction or withdrawal. 

An alternative strategy for the treatment of AD is the use of the NMDA glutamate-receptor antagonist memantine (Namenda). Memantine produces a use-dependent blockade of NMDA receptors. In patients with moderate to severe AD, use of memantine is associated with a reduced rate of clinical deterioration. Whether this is due to a true diseasemodifying effect, possibly reduced excitotoxicity, or is a symptomatic effect of the drug is unclear. Adverse effects of memantine usually are mild and reversible, and may include headache or dizziness. 

An in vitro study in rats suggested that memantine does not attenuate the anticholinesterase effects of galantamine at therapeutic concentrations. A study in 15 healthy subjects found that the concurrent use of extended-re-lease galantamine 16 mg daily with memantine 10 mg twice daily for 12 days did not affect the pharmacokinetics of galantamine and generally did not increase the incidence of adverse effects, although dizziness may have been more common. ... 

Drugs that make the urine alkaline (e.g. sodium bicarbonate, carbonic anhydrase inhibitors) will reduce the elimination of memantine. Memantine should be used with caution with other NMDA antagonists, such as amantadine, ketamine and dextromethorphan, or concurrent use should be avoided, because of the theoretical increased risk of adverse effects. Memantine is predicted to interact with other drugs eliminated by the same renal secretion mechanism, but no important interaction was seen with glibenclamide, hydrochlorothiazide, metformin or triamterene. 

The clearance of memantine was markedly reduced (by about 80%) when the urine was alkaline (pH 8). This would be expected to lead to memantine accumulation and an increase in adverse effects. Drugs that could in-... 

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