Related Experiment Video
Updated: Jul 12, 2026
07:30
Single Cell Measurement of Dopamine Release with Simultaneous Voltage-clamp and Amperometry
Published on: November 21, 2012
Metabolic Precursors to Amphetamine and Methamphetamine
1Clinical Investigations, Wilford Hall Medical Center, Lackland AFB, TX, USA.
Forensic Science Review
|August 14, 2015
Summary
Determining the source of amphetamine or methamphetamine is complex, as many legitimate substances can metabolize into these drugs. This review details fourteen precursors to aid in interpreting positive drug test results.
Area of Science:
- Forensic Toxicology
- Pharmacology
- Analytical Chemistry
Background:
- Amphetamine and methamphetamine testing presents interpretation challenges.
- Identifying the origin of amphetamines in samples is difficult.
- Legitimate medical use of amphetamines is rare, complicating positive findings.
Purpose of the Study:
- To review fourteen metabolic precursors of amphetamine or methamphetamine.
- To provide information for evaluating the origin of amphetamine/methamphetamine in samples.
Main Methods:
- Literature review of medical use, metabolism, and analysis of precursor compounds.
- Identification of fourteen specific metabolic precursors.
Main Results:
- Fourteen compounds identified as potential metabolic precursors to amphetamine or methamphetamine.
- Details on medical use, metabolism, and analytical methods for each precursor are provided.
Conclusions:
- Understanding precursor metabolism is crucial for accurate interpretation of amphetamine and methamphetamine testing.
- This review offers comprehensive data to differentiate drug use from legitimate precursor metabolism.
Related Concept Videos
01:27Adrenergic Neurons: Neurotransmission
Postganglionic sympathetic fibers (except those supplying the sweat glands) releasing noradrenaline or norepinephrine are called noradrenergic or adrenergic neurons. Noradrenaline, dopamine, adrenaline, or epinephrine are collectively called "catecholamines" as they contain a catechol moiety and an amine side chain. The five stages of neurotransmitter release involve their synthesis, storage, release, reuptake and metabolism.
Synthesis: Catecholamine synthesis requires tyrosine, which is taken...
Synthesis: Catecholamine synthesis requires tyrosine, which is taken...
01:25Adrenergic Agonists: Indirect-Acting Agents
Indirect-acting adrenergic agonists potentiate the effects of endogenous catecholamines through different mechanisms without directly binding to adrenoceptors.
One mechanism involves depleting stored catecholamines by displacing them from synaptic vesicles. These agents, known as "displacers," are transported into vesicles at the expense of noradrenaline. Examples include amphetamine and tyramine, which lack a catechol moiety, resulting in prolonged action, improved oral bioavailability, and...
One mechanism involves depleting stored catecholamines by displacing them from synaptic vesicles. These agents, known as "displacers," are transported into vesicles at the expense of noradrenaline. Examples include amphetamine and tyramine, which lack a catechol moiety, resulting in prolonged action, improved oral bioavailability, and...
01:28Adrenergic Agonists: Mixed-Action Agents
Mixed-action adrenergic agonists, like ephedrine and pseudoephedrine, directly and indirectly affect adrenergic receptors. These agents stimulate adrenoceptors and indirectly release stored neurotransmitters, amplifying the adrenergic response.
Ephedrine and pseudoephedrine lack a catecholamine group, making them less susceptible to degradation by metabolic enzymes. They have increased oral bioavailability and lipophilicity, resulting in a longer duration of action. Their response is reduced by...
Ephedrine and pseudoephedrine lack a catecholamine group, making them less susceptible to degradation by metabolic enzymes. They have increased oral bioavailability and lipophilicity, resulting in a longer duration of action. Their response is reduced by...
01:16Adrenergic Agonists: Chemistry and Structure-Activity Relationship
Adrenergic agonists' structure-activity relationship (SAR) determines their selectivity and efficacy. These agonists comprise a phenylethylamine moiety with an aromatic ring and an ethylamine side chain.
Aromatic ring substitutions: Substituting the aromatic ring with –OH groups at positions 3 and 4 yields catecholamines (e.g., epinephrine), which have a high affinity for adrenoceptors. Hydrogen bonding between –OH groups and receptors enhances adrenergic activity.
Separation of the aromatic...
Aromatic ring substitutions: Substituting the aromatic ring with –OH groups at positions 3 and 4 yields catecholamines (e.g., epinephrine), which have a high affinity for adrenoceptors. Hydrogen bonding between –OH groups and receptors enhances adrenergic activity.
Separation of the aromatic...
01:29Drugs Affecting Neurotransmitter Synthesis
Drugs affecting neurotransmitter synthesis can impact the adrenergic neuron and the synthesis of neurotransmitters. For example, α-methyltyrosine and carbidopa target specific enzymes involved in catecholamine synthesis. α-methyltyrosine inhibits the enzyme tyrosine hydroxylase, which converts tyrosine into dopamine. By blocking this enzyme, α-methyltyrosine reduces dopamine production and other catecholamines. Carbidopa, on the other hand, inhibits the enzyme dopa decarboxylase, which converts...
01:24CNS Stimulants: Cocaine, Amphetamines and Cannabinoids
CNS stimulants, such as cocaine, amphetamines, and cannabinoids, have varying structures and mechanisms of action that lead to different therapeutic effects and side effects. Cocaine, with its molecular formula C17H21NO4, is a tropane alkaloid and a tertiary amino compound. It has two chemical forms: the hydrochloride salt and the "freebase." The former is in powder form, while the latter involves removing the hydrochloride salt to create a form that can be smoked. Cocaine exerts its effects by...