L-DOPA
- L-DOPA
- L-3 ,4- dihydroxyphenylalanine
- (S )-2- amino-3- (3,4- dihydroxyphenyl ) propanoic acid
- (S )-2- amino-3- (3,4- dihydroxyphenyl ) propionic acid
N04BA01
White solid
Parkinson drug
Dopamine precursor
276-278 ° C or 284-285 ° C
Soluble in water
Attention
1780 mg · kg -1 ( LD50, rat, oral)
Template: Infobox chemical / molecular formula search available
Levodopa, L- DOPA is the abbreviation for L-3 ,4- dihydroxyphenylalanine, a non-proteinogenic α - amino acid that is formed in the body from tyrosine by the enzyme tyrosine hydroxylase.
Biological Significance
L- DOPA is a precursor in the biosynthesis of the messengers ( neurotransmitters) epinephrine, norepinephrine and dopamine, and the melanins.
In mussels L- DOPA is the main component of the adhesive with which mussels attach to solid surfaces. The function of L -dopa is that it incorporated into the protein chain of the adhesive, due to its hydroxyl groups enhances the hydrophilicity. This is important so that the emitted into the surrounding seawater adhesive achieves better adhesion effect with the surface of the substrate.
Use as drug
As drug L- DOPA is usually denoted by its generic name levodopa. In many European countries, including Germany, Austria and Switzerland levodopa prescription.
Pharmacology
Since levodopa is able to cross the blood -brain barrier, it is suitable for the treatment of diseases that result from a lack of said neurotransmitters, such as Parkinson's disease, which is associated with a lack of dopamine. To prevent the premature breakdown of levodopa in the periphery (outside the Liquorraumes ) to dopamine, it is combined with either a decarboxylase inhibitor ( carbidopa or benserazide ) or a catechol-O- methyltransferase inhibitor ( entacapone, tolcapone ). After passing through the blood -brain barrier of levodopa is then metabolized to dopamine, which develops the actual desired pharmacological activity. Thus, it is at a levodopa prodrug.
Areas of application
As drug levodopa has been associated with the brand name Madopar 1973 by Hoffmann -La Roche for the treatment of Parkinson's disease on the market. The fixed combination of levodopa carbidopa was added in 1977 by the World Health Organization (WHO ) in the list of essential drugs of the World Health Organization. Because of side effects in the long-term use in Parkinson's patients trying but today especially in younger Parkinson's patients to delay treatment with levodopa and primarily to treat with dopamine agonists.
Also, the Restless Legs Syndrome (RLS ) is often treated with levodopa. Levodopa is increased also in the treatment of Huntington's disease is used.
Side effects
Side effects you may experience nausea, dizziness and circulatory problems. At high doses up to overdose side effects such as dyskinesia or psychological symptoms such as insomnia, and hallucinations may occur. Sudden discontinuation may lead to levodopa withdrawal syndrome.
Chemical Properties
L- DOPA is readily soluble in water ( 3.3 g / l at 25 ° C), sparingly soluble in ethanol and insoluble in diethyl ether.
Strukturabkömmlinge
The substituted at C-2 with the fluorine isotope 18F derivative 18F -DOPA ( fluorodopa ( 18 F) ) is used for the diagnosis of neuroendocrine tumors in positron emission tomography.
Trivia
The film Awakenings (German Awakenings, starring Robert De Niro and Robin Williams, directed by Penny Marshall, 1990), based on a book by Oliver Sacks explores the short-term treatment success of patients in the European sleeping sickness with L- DOPA.
Trade names
- Benserazide: Levobens (A), levodopa comp ( D), Levopar (D), Madopar (D, A, CH), PK - Levo (D), Restex (D, A) and more generic
- With carbidopa: duodopa (D, A, CH), Isicom (D), Sinemet (A, CH), Stalevo (D, A, CH), Striaton (D) and other generic
- With carbidopa and entacapone: Stalevo (D, A, CH)