CNS Stimulants | Definition | Classification and Mechanisms

CNS Stimulants are drugs that enhance brain activity, increasing alertness, focus, energy, and sometimes improving mood and performance.

CNS stimulants are drugs that increase activity of the central nervous system, particularly enhancing alertness, attention, wakefulness, and in some cases, motor activity.
They act primarily by increasing levels of dopamine, norepinephrine, or serotonin.

Amphetamines
- Examples: Amphetamine, Dextroamphetamine, Methylphenidate
- Mechanism: Increase dopamine and norepinephrine release; inhibit their reuptake → ↑ alertness, focus, energy.
- Uses:
  - ADHD
  - Narcolepsy
  - Occasionally for obesity (appetite suppression)
- Note: High abuse potential; classified as controlled substances.
Methylxanthines
- Examples: Caffeine, Theophylline
- Mechanism:
  - Inhibit phosphodiesterase → ↑ cAMP
  - Block adenosine receptors → ↓ drowsiness
- Uses:
  - Caffeine: Enhances wakefulness
  - Theophylline: Previously for asthma/COPD (now rarely used)
  - Note: Mild stimulants, widely consumed in daily life.
Cocaine
- Mechanism: Blocks reuptake of dopamine, norepinephrine, and serotonin → intense euphoria & energy.
- Uses: Rarely in ENT procedures (anesthetic & vasoconstrictor).
- Risks: High abuse/addiction potential; causes serious complications (CV issues, seizures, psychosis).
Others – Wakefulness-Promoting Agents
- Examples: Modafinil, Armodafinil
- Mechanism: Atypical stimulants; act on dopamine transporters (mechanism not fully understood).
- Uses:
  - Narcolepsy
  - Shift Work Sleep Disorder
  - OSA (adjunct to CPAP)
  - Off-label: ADHD, cognitive enhancement
- Note: Lower abuse potential and fewer side effects than amphetamines.