Mechanism of Action of Amphetamines

Amphetamines, such as dextroamphetamine and methamphetamine, are central nervous system stimulants. Their primary mechanism involves increasing the levels of key neurotransmitters in the brain—specifically dopamine, norepinephrine, and serotonin. Here's a breakdown of how amphetamines work:

1. Increased Neurotransmitter Release: Amphetamines stimulate the release of dopamine and norepinephrine from presynaptic nerve terminals in the brain.

2. Inhibition of Reuptake: They block the reuptake of these neurotransmitters by inhibiting their transporters. This means more dopamine and norepinephrine remain in the synaptic cleft, leading to prolonged stimulation of postsynaptic neurons.

3. Inhibition of Monoamine Oxidase (MAO): Amphetamines also inhibit the action of MAO, an enzyme responsible for breaking down neurotransmitters like dopamine and norepinephrine. This further increases their levels in the brain.

4. Direct Activation of Receptors: In some cases, amphetamines may directly stimulate the receptors of these neurotransmitters.

The overall effect is heightened alertness, energy, focus, and feelings of euphoria. However, this also leads to increased heart rate, blood pressure, and potential for addiction due to the surge in dopamine.

Uses of Amphetamines:

1. Attention-Deficit Hyperactivity Disorder (ADHD): Amphetamines like Adderall (a mixture of amphetamine salts) are commonly prescribed to improve focus, attention, and reduce impulsivity in people with ADHD.

2. Narcolepsy: These drugs are used to treat narcolepsy, a condition that causes excessive daytime sleepiness. Amphetamines help keep people awake and alert.

3. Obesity (Short-term use): In certain cases, amphetamines are prescribed to reduce appetite and promote weight loss, though this is typically for short-term use due to the potential for abuse and side effects.

4. Treatment-Resistant Depression: In some cases, amphetamines may be used as an adjunct treatment for depression, particularly in patients who have not responded well to traditional antidepressants.

5. Cognitive Enhancement (Off-label): Some individuals use amphetamines off-label to enhance cognitive performance, particularly in high-stress academic or work environments, though this use is controversial.

Risks & Side Effects:

• Addiction and abuse potential
• Increased blood pressure and heart rate
• Insomnia, anxiety, and agitation
• Appetite suppression
• Long-term use can lead to psychosis or cardiovascular complications