Central Nervous System Stimulants and Attention- Deficit/Hyperactivity Disorder

Question 1

AMPHE TAMINES

Answer 1

Mechanismofaction
• Release norepinephrine
• Release dopamine

• Pharmacologic effects • CNS
• Cardiovascular system • Tolerance
• With regular use, tolerance develops to elevation of mood, suppression of appetite, and stimulation of the heart and blood vessels
• Physical dependence
• Abstinence syndrome with abrupt withdrawal
• Abuse
• High potential for abuse due to euphoria
• Adverse effects
• CNS stimulation
• Weight loss
• Cardiovascular effects • Psychosis

• Acute toxicity
• Dizziness, confusion, hallucinations, paranoid delusions,
palpitations, dysrhythmias, and hypertension
• Death is rare
• Fatal overdose: Convulsions, coma, and cerebral hemorrhage

Acute toxicity • Treatment
• Hallucinations: Chlorpromazine
• Hypertension: Alpha-adrenergic blocker (e. g. , phentolamine);
chlorpromazine helps lower blood pressure
• Seizures: Diazepam
• Acidifying the urine can accelerate amphetamine excretion

Therapeutic uses

• ADHD
• Narcolepsy

Question 2

METHYLPHENIDATE

Answer 2

ADHD and narcolepsy
• Trade names
• Ritalin, Metadate, Methylin, Concerta, and Daytrana
• 50:50 mixture of dextro and levo isomers
• Preparations, dosage, and administration
• Immediate release
• Ritalin and Methylin
• Sustained release
• Ritalin SR, Metadate ER, and Quillivant XR
• Once-daily dosing
• Concerta, Metadate CD, Ritalin LA, Daytrana, and Biphentin (Canadian)

Question 3

DEXMETHYLPHENIDATE [FOCALIN]

Answer 3

• DrugforADHD
• Dextroisomerofmethylphenidate
• 50:50mixtureofdextroandlevoisomers

Question 4

METHYLXANTHINES

Answer 4

Derivativesofxanthine • Caffeine
• Few clinical applications
• Widespread ingestion for nonmedical purposes
• Dietary sources
• Chocolate • Soft drinks

• Mechanism of action
• Reversible blockade of adenosine receptors
• Calcium permeability
• Accumulation of cyclic adenosine monophosphate
• Low doses
• Decrease drowsiness and fatigue
• Increase capacity for prolonged intellectual exertion
• Increasing doses
• Nervousness, insomnia, and tremors
• Seizures with very large amounts

Pharmacokinetics
• Readily absorbed from the gastrointestinal tract
• Achieve peak plasma levels within 1 hour
• Eliminated by hepatic metabolism

Question 5

• Modafinil [Provigil, Alertec]

Answer 5

• Therapeutic use
• Promotes wakefulness
• Narcolepsy
• Shift-work sleep disorder
• Obstructive sleep apnea/hypopnea syndrome
• Mechanism of action
• Pharmacokinetics
• Rapidly absorbed in the gastrointestinal tract
• Elimination by hepatic metabolism
• Half-life: About 15 hours

Question 6

Atomoxetine

Answer 6

• Description and therapeutic effects
• Nonstimulant
• No potential for abuse
• Administered once a day

Mechanism of action
• Selective inhibitor of norepinephrine reuptake • Pharmacokinetics
• Plasma levels peak within 1 to 3 hours
• Metabolized in the liver

• Adverse effects
• Gastrointestinal reactions
• Reduced appetite
• Dizziness
• Somnolence
• Mood swings
• Trouble sleeping

Question 7

• Drugtherapyalpha2-adrenergicagonists:Guanfacine

Answer 7

Activates presynaptic alpha2-adrenergic receptors in the brain
• Principal side effects: Somnolence, fatigue, and reduced blood pressure

Question 8

• Drugtherapyalpha2-adrenergicagonists:Clonidine

Answer 8

Alpha2 agonist

• Principal side effects: Somnolence, fatigue, and hypotension