CH 17 STIMULANTS

Chapter 17: Stimulants

CNS Stimulants: Medically Approved Uses

  • Attention-Deficit/Hyperactivity Disorder (ADHD): Treatments aim to increase focus and reduce impulsivity.
  • Narcolepsy: Helps manage excessive daytime sleepiness.
  • Reversal of Respiratory Distress: Certain stimulants can aid in respiratory function.

Categories of CNS Stimulants

  • Amphetamines: Primarily act on the cerebral cortex, stimulating norepinephrine and dopamine release.
  • Analeptics (Caffeine): Target brainstem and medulla to enhance alertness.
  • Anorexiants: Act on the hypothalamic and limbic areas to suppress appetite.

Attention-Deficit/Hyperactivity Disorder (ADHD)

Pathophysiology
  • Involves dysregulation of neurotransmitters:
    • Serotonin
    • Norepinephrine
    • Dopamine
Epidemiology
  • Usually diagnosed in children before age 7.
  • More prevalent in boys compared to girls.
Characteristics
  • Inattentiveness: Difficulty in focusing on tasks.
  • Restlessness and Hyperactivity: Excessive movement and inability to sit still.
  • Impulsivity: Quick decisions without thinking.
  • Inability to Complete Tasks: Frequently started but unfinished activities.
  • Poor Coordination: Difficulty with motor skills.

Narcolepsy

Characteristics
  • Episodes of extreme drowsiness during normal waking activities, such as:
    • Driving
    • Talking
  • May experience sleep paralysis, a temporary inability to move or speak while falling asleep or waking.

Amphetamines

Action
  • Enhance release of norepinephrine and dopamine.
  • Inhibit reuptake of these neurotransmitters, leading to increased levels in the brain.
Side Effects/Adverse Reactions
  • Physical Symptoms: Dizziness, headache, tachycardia, palpitations, hypertension.
  • Emotional Responses: Nervousness, irritability, euphoria, potential for insomnia.
  • Others: Dry mouth, weight loss, diarrhea, erectile dysfunction, risk of psychosis with excessive use.

Amphetamine-like Drugs for ADHD

  • Methylphenidate and Dexmethylphenidate
    • Used to improve attention span and cognitive performance.
    • Decrease impulsiveness, hyperactivity, and restlessness.

Amphetamine-like Drugs for Narcolepsy

  • Methylphenidate: Increases focus and cognitive performance.
  • Modafinil: Promotes wakefulness; works by inhibiting dopamine and norepinephrine reuptake, stimulating the CNS, and enhancing serotonin action.

Methylphenidate

Uses
  • Treats ADHD and narcolepsy, helps in increasing attention span.
Interactions
  • Caffeine: Can increase stimulant effects.
  • Other medications: May enhance or reduce the effects of various drugs including anticoagulants, barbiturates, and antihypertensives.
Side Effects/Adverse Reactions
  • Common Issues: Tachycardia, restlessness, dizziness, blurred vision, euphoria, confusion, insomnia.
  • Weight-related Concerns: Anorexia, dry mouth, diarrhea, potential for seizures.

Clinical Judgment: Methylphenidate

Assessment and Interventions
  • Administration before meals is advised.
  • Limit caffeine intake.
  • Monitor for irregular heartbeats and assess vital signs.
  • Recommended to taper off to avoid withdrawal symptoms. Use sugarless gum for dry mouth.

Anorexiants

  • Causes appetite suppression by acting on the hypothalamic and limbic systems.
  • Contraindications: Not recommended for children under 12.
Side Effects
  • Similar to stimulants: restlessness, euphoria, insomnia, tachycardia, hypertension; also includes risk of seizures and erectile dysfunction.

Analeptics

  • Caffeine: Utilized for neonatal apnea and promoting alertness, but may cause headaches, withdrawal symptoms, and cardiovascular issues.

Practice Questions

  1. Teaching Effectiveness: What indicates a child on methylphenidate requires more teaching?
  2. Drug Prescription: What medication is likely prescribed for ADHD?
  3. Contraindications: What condition disqualifies a patient from taking methylphenidate?
  4. Parent Education: What common misconceptions about ADHD should be addressed with parents?