Theanine - Codeine Phosphate Interaction

Interaction Details

Codeine Phosphate is classified as belonging to the following category: Cns Depressants

Theoretically, theanine might have additive sedative effects when used in conjunction with CNS depressants. However, it is unclear if this concern is clinically relevant.
Theoretically, theanine may compete with glutamate and/or increase plasma gamma-aminobutyric acid (GABA) levels, which could cause CNS depression. In one clinical study, some subjects taking oral theanine reported drowsiness.

Interaction Rating

Likelihood of Occurrence

Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Pharmacist Analysis

L-theanine is most commonly taken to help improve some aspects of cognitive function. However, it is also sometimes used to treat anxiety and reduce stress as it may have a mild sedative effect. Studies are lacking, but some report theanine's anti-anxiety effects might be due to its effects on glutamate receptors and possibly an effect on certain inhibitory neurotransmitters like glycine or gamma-aminobutyric acid (GABA).

The sedative effects of L-theanine appear to be relatively mild, but it is important to know if combined with other drugs that may cause sedation as well due to the potentially additive effects.

References

• Hidese S, Ota M, Wakabayashi C, et al. Effects of chronic l-theanine administration in patients with major depressive disorder: an open-label study. Acta Neuropsychiatr 2017;29(2):72-9.
• Tsuchiya T, Honda H, Oikawa M, et al. Oral administration of the amino acids cystine and theanine attenuates the adverse events of S-1 adjuvant chemotherapy in gastrointestinal cancer patients. Int J Clin Oncol 2016;21(6):1085-90.

Codeine Phosphate Overview

• Codeine is used to relieve mild to moderate pain. It is also used, usually in combination with other medications, to reduce coughing. Codeine will help relieve symptoms but will not treat the cause of symptoms or speed recovery. Codeine belongs to a class of medications called opiate (narcotic) analgesics and to a class of medications called antitussives. When codeine is used to treat pain, it works by changing the way the brain and nervous system respond to pain. When codeine is used to reduce coughing, it works by decreasing the activity in the part of the brain that causes coughing.

• Codeine is also available in combination with acetaminophen (Capital and Codeine, Tylenol with Codeine), aspirin, carisoprodol, and promethazine and as an ingredient in many cough and cold medications. This monograph only includes information about the use of codeine. If you are taking a codeine combination product, be sure to read information about all the ingredients in the product you are taking and ask your doctor or pharmacist for more information.

Theanine - More Interactions

Theanine interacts with 558 drugs

Interaction Rating Key

These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.