Drug Interaction Report
1 potential interaction and/or warning found for the following 2 drugs:
- Namenda (memantine)
- trimethoprim
Interactions between your drugs
trimethoprim memantine
Applies to: trimethoprim, Namenda (memantine)
MONITOR: Trimethoprim may decrease the renal clearance of amantadine and memantine. The mechanism may be competition for organic cation transporter-2 (OCT-2)-mediated secretion in the kidney tubule of which amantadine, memantine, and trimethoprim are substrates. Trimethoprim may also inhibit OCT-2. Increased levels of amantadine and memantine may increase the risk of neurological side effects such as mental confusion, delirium, and myoclonus. Serum trimethoprim levels may also be increased.
MANAGEMENT: Caution and monitoring for nervous system side effects is recommended if trimethoprim is used with either amantadine or memantine. Patients should be advised to contact their physician if they experience nervous system side effects such as mental confusion and myoclonus.
References (5)
- Speeg KV, Leighton JA, Maldonado AL (1989) "Case report: toxic delirium in a patient taking amantadine and trimethoprim sulfamethoxazole." Am J Med Sci, 298, p. 410-2
- (2022) "Product Information. Bactrim (sulfamethoxazole-trimethoprim)." Roche Laboratories
- Cerner Multum, Inc. "UK Summary of Product Characteristics."
- Cerner Multum, Inc. "Australian Product Information."
- Moellentin D, Picone C, Leadbetter E (2008) "Memantine-induced myoclonus and delirium exacerbated by trimethoprim." Ann Pharmacother, 42, p. 449-7
Drug and food/lifestyle interactions
No alcohol/food interactions were found with the drugs in your list. However, this does not necessarily mean no food interactions exist. Always consult your healthcare provider.
Therapeutic duplication warnings
No duplication warnings were found for your selected drugs.
Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.
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Drug Interaction Classification
| Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. | |
| Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. | |
| Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan. | |
| No interaction information available. |
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Further information
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