Deprenyl is a medication that works by interfering with the monoamine oxidase B enzyme. This leads to an accumulation of dopamine, a neurotransmitter which is lacking in a person with Parkinson's disease. Phenylalanine, on the other hand, is an amino acid which you must get in your diet. Taking the synthetic form along with deprenyl is not recommended.
Monoamine Oxidase
Monoamine oxidase is an enzyme, or protein that cells use to make a biochemical reaction go faster. It has been found inside of most of the cells in the body, with the exception of the red blood cells. This protein has two main functions. It removes substances called amines from serotonin, dopamine and norepinephrine to make them inactive, and lowers the absorption of tyramine. Thus, a monoamine oxidase inhibitor interferes with monoamine oxidase and leads to an accumulation of serotonin, dopamine and norepinephrine, and an increase in tyramine.
Deprenyl
Deprenyl, generic name selegiline, is a monoamine oxidase inhibitor. There are actually two kinds of monoamine oxidase. Monoamine oxidase A affects the metabolism of serotonin, dopamine and norepinephrine, while monoamine oxidase B only affects dopamine. At the normal dose, deprenyl is a monoamine oxidase B inhibitor; if you take it at a high enough dose, however, it will inhibit monoamine oxidase A, as explained in “Basic & Clinical Pharmacology” by Michael Aminoff, M.D., Professor in the Department of Neurology at the University of California. Deprenyl is used in the treatment of Parkinson's disease, in addition to the medication levodopa. It may also be used to treat major depression.
Phenylalanine
Phenylalanine is an amino acid. Amino acids are used by cells to make heme, which becomes part of hemoglobin; purines and pyrimidines, which make up RNA and DNA; the pigment melanin; enzymes and proteins. Your cells can make 11 amino acids. There are nine amino acids, including phenylalanine, which the cells cannot make. Once they have phenylalanine, they use an enzyme called phenylalanine hydroxylase to change phenylalanine to the amino acid tyrosine, as described in “Principles of Medical Biochemistry” by Gerhard Meisenberg, Ph.D. of the Department of Biochemistry at Ross University School of Medicine. If you do not have enough of the phenylalanine hydroxylase enzyme, phenylalanine will accumulate to toxic levels in the body. This is the cause of the hereditary disease phenylketonuria.
Deprenyl and Phenylalanine
According to the University of Maryland Medical Center, there are three forms of the amino acid phenylalanine. L-phenylalanine is the natural amino acid obtained from your diet, D-phenylalanine is a kind of phenylalanine that has been manufactured in a lab, while the DL-phenylalanine form is a 50/50 combination. Although there have been some clinical studies involving D-phenylalanine and its effect on Parkinson's disease and pain, and the effect of phenylalanine on depression, more studies must be done. It is known, however, that phenylalanine can interact with antipsychotic medications, levodopa, baclofen, monoamine oxidase inhibitors in general and with deprenyl in particular. Taking L-phenylalanine and deprenyl can increase the antidepressant activity of phenylalanine, and this is why the Medical Center does not recommend taking them together.
References
- “Basic & Clinical Pharmacology”; Bertram Katzung et al.; 2009
- “Goodman & Gilman's The Pharmacological Basis of Therapeutics”; Laurence Brunton; 2011
- “Greenspan's Basic & Clinical Endocrinology”; David Gardner and Dolores Shoback; 2007
- “Principles of Medical Biochemistry”; Gerhard Meisenberg and William Simmons; 1998
- “Tintinalli’s Emergency Medicine: A Comprehensive Study Guide”; Judith Tintinalli et al.; 2004
- University of Maryland Medical Center; Phenylketonuria; Benjamin Van Voorhees, M.D.; 2009
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