Memantine

About Memantine

Memantine blocks the NMDA receptor, damping the excess glutamate signaling thought to damage nerve cells in Alzheimer’s disease. It is labeled for moderate to severe dementia of the Alzheimer’s type; it helps symptoms but does not cure the disease. Namzaric combines it with donepezil in one extended-release capsule for people already stabilized on 10 mg of donepezil a day.

Dizziness, headache, confusion and constipation are the most common side effects of the tablets, and headache, diarrhea and dizziness of the capsule; there is no boxed warning. Conditions and medicines that make the urine alkaline slow its removal and can raise its levels, and it has not been systematically studied in people with a seizure disorder. Mild to moderate kidney or liver impairment needs no dose change; with severe kidney impairment (creatinine clearance 5 to 29 mL/min) the target is 5 mg twice a day for tablets, 14 mg a day for the capsule and 14 mg/10 mg for Namzaric.

The dose rises no faster than one step a week. Tablets and the oral solution start at 5 mg once a day and go up in 5 mg steps to 20 mg a day, taken as 10 mg twice a day. Extended-release capsules start at 7 mg once a day and go up in 7 mg steps to 28 mg; a switch from 10 mg tablets twice a day to a 28 mg capsule is made the day after the last tablet. Namenda tablets, oral solution and Namenda XR are listed as discontinued in the Orange Book; generics of each are sold, and Namzaric is still marketed alongside its generics.

Taking Memantine

How to take it

Once a day for the capsule, twice a day for tablets above 5 mg, with or without food. Capsules can be swallowed whole or opened and the whole contents sprinkled on applesauce and swallowed without chewing. Measure the oral solution with the syringe supplied and do not mix it with any other liquid.

If you miss a dose

Take it as soon as you remember, unless it is nearly time for the next dose; then skip it and do not double up. If several days are missed, call the prescriber before restarting.

Storage

At room temperature, tightly closed, out of reach of children; the combination capsule in a tight, light-resistant container.

Interactions to know about

Acetazolamide, sodium bicarbonate and other medicines that make the urine alkaline, and conditions that raise urine pH such as severe urinary infections, can make memantine build up. The label advises caution with other NMDA blockers such as amantadine, ketamine and dextromethorphan. For the combination with donepezil, tell the anesthetist before surgery, and report a slow heartbeat, fainting, signs of stomach bleeding or persistent vomiting.

This summarizes the official prescribing information. Your prescriber’s and pharmacist’s instructions, and the leaflet that comes with your medicine, take priority.

Why the cash price for Memantine differs from pharmacy to pharmacy

Memantine tablets come from many makers and cost pharmacies little, so a quote is mostly dispensing fee and markup. The extended-release capsules have fewer makers and are usually quoted higher for the same daily dose, and the oral solution, sold by the bottle, higher again. The Namzaric combination is sometimes quoted above memantine and donepezil bought as two generics and sometimes below, since one prescription carries one fee.

Ways to pay less for Memantine without insurance

• If the once-daily capsule is quoted high, ask the prescriber whether twice-daily tablets would suit you; the doses differ, so the switch is theirs to make.
• For Namzaric, ask the pharmacy to quote the combination and the two separate generics.
• If the oral solution was prescribed for swallowing difficulty, ask whether a capsule opened onto applesauce would do.
• Once the dose is settled, ask for a ninety-day supply.
• Upload the prescription to Script Unlock so licensed pharmacies can quote their cash price. You pay the pharmacy directly.

Questions to ask your pharmacist about Memantine

1. 1.Is this the tablet or the extended-release capsule?
2. 2.What should we do if several doses are missed?
3. 3.Is the dose adjusted for kidney function?
4. 4.Does it interact with dextromethorphan cough medicine, amantadine or antacids?
5. 5.How can the capsule be given if swallowing is difficult?

Related medications