Chapter 31: CNS Stimulants & ADHD Flashcards
CNS stimulants
Increase the activity of central nervous system (CNS) neurons
Enhance neuronal excitation; a few suppress neuronal inhibition
In sufficient doses, all can cause convulsions
Limited clinical applications -Limited to ADHD, narcolepsy, hyperactivity dz
amphetamines chemistry
Dextroamphetamine and levoamphetamine
Amphetamine
Lisdexamfetamine
Methamphetamine
amp MOA
Release norepinephrine
Release dopamine
amp pharm effects
CNS
Cardiovascular system
amp tolerance
With regular use, tolerance develops to elevation of mood, suppression of appetite, and stimulation of the heart and blood vessels
AMP physical dependence and abuse
Physical dependence
Abstinence syndrome with abrupt withdrawal
Abuse
High potential for abuse due to euphoria
amp ADR
CNS stimulation
Weight loss
Cardiovascular effects
Psychosis
amp acute toxicity
Dizziness, confusion, hallucinations, paranoid delusions, palpitations, dysrhythmias, and hypertension
Death is rare
Fatal overdose: Convulsions, coma, and cerebral hemorrhage
amp acute tox tx
Hallucinations: Chlorpromazine
Hypertension: Alpha-adrenergic blocker (e.g., phentolamine); chlorpromazine helps lower blood pressure
Seizures: Diazepam
Acidifying the urine can accelerate amphetamine excretion
amp therapeutic uses
ADHD
Narcolepsy
amp preps
Dextroamphetamine sulfate
Immediate release
Extended release
Amphetamine/dextroamphetamine mixture
Immediate release
Extended release
Lisdexamfetamine [Vyvanse]
Methamphetamine [Desoxyn]
Methylphenidate and Dexmethylphenidate
Nearly identical in structure and pharmacologic actions
Pharmacology of both drugs nearly identical to that of amphetamines
methylphenidate
ADHD and narcolepsy
Trade names
Ritalin, Metadate, Methylin, Concerta, and Daytrana
50:50 mixture of dextro and levo isomers
methylphenidate prep
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)
Dexmethylphenidate [Focalin]
Drug for ADHD
Dextro isomer of methylphenidate
50:50 mixture of dextro and levo isomers
methyl xanthines
Derivatives of xanthine
Caffeine
Few clinical applications
Widespread ingestion for nonmedical purposes
Dietary sources
Chocolate
Soft drinks
Coffee
Typically consumption. Is an 200 mg/day
Adults can have type consumption 400 mg/day
ex of caffeine
Brewed coffee 96 mg
Instant coffe 62 mg
Expression 1 oz 64 mg
Black tea 47 mg
Green tea 28 mg
Cola is 22 mg
Energy drink 8 ox 29 mg
1 oz energy short 215 mg
methylzanthine MOA
Reversible blockade of adenosine receptors
Calcium permeability
Accumulation of cyclic adenosine monophosphate
methylzanthine dosage effects
Low doses
Decrease drowsiness and fatigue
Increase capacity for prolonged intellectual exertion
Increasing doses
Nervousness, insomnia, and tremors
Seizures with very large amounts
methrylxanthine pharm effects
CNS: hyperactivity, irritability
Heart: palpitations
Blood vessels: HTN
Bronchi: SOB
Kidney: increased urination
Reproduction
methylxanthine pharmcakinetics
Readily absorbed from the gastrointestinal tract
Achieve peak plasma levels within 1 hour
Eliminated by hepatic metabolism
methylxanthine therapeutic uses
Neonatal apnea
Promoting wakefulness
Other applications
methylxanthine acute tox
Stimulation of the CNS
Tachycardia
Respiratory stimulation
Sensory phenomena
Modafinil [Provigil, Alertec] uses
Promotes wakefulness
Narcolepsy
Shift-work sleep disorder
Obstructive sleep apnea/hypopnea syndrome
Modafinil [Provigil, Alertec] pharmacokinetics
Rapidly absorbed in the gastrointestinal tract
Elimination by hepatic metabolism
Half-life: About 15 hours
Modafinil [Provigil, Alertec] ADRs
Headache
Nausea
Nervousness
Diarrhea
Rhinitis
Modafinil [Provigil, Alertec] drug interactions
Oral contraceptives
Cyclosporine
adhd in children s/sx
Inattention
Hyperactivity
Impulsivity
Fidgety
Unable to concentrate
Unable to wait his or her turn
Switches excessively from one activity to another
Calls out excessively in class
Present before the age of 7 years
Present for at least 6 months
adhd in children: management overview
Cognitive therapy
Stimulant drugs
adhd in children drug therapy: cns stimulants
Methylphenidate [Ritalin, Concerta, others]
Dexmethylphenidate [Focalin]
Dextroamphetamine
Amphetamine mixture [Adderall]
Pemoline [Cylert]
adhd in children drug therapy: nonstimulants
Atomoxetine
Description and therapeutic effects
Nonstimulant
No potential for abuse
Administered once a day
Atomoxetine MOA
Selective inhibitor of norepinephrine reuptake
Atomoxetine pharmacokinetics
Plasma levels peak within 1 to 3 hours
Metabolized in the liver
Atomoxetine adr
Gastrointestinal reactions
Reduced appetite
Dizziness
Somnolence
Mood swings
Trouble sleeping
Atomoxetine drug interactions
Monoamine oxidase inhibitors (isocarboxazid, phenelzine)
CYP2D6 (paroxetine, fluoxetine, quinidine)
Atomoxetine prep/dose
Children who weigh less than 70 kg
Children who weigh 70 kg or more
adhd in children drug therapy alpha2-adrenergic agonists: Guanfacine
Activates presynaptic alpha2-adrenergic receptors in the brain
Principal side effects: Somnolence, fatigue, and reduced blood pressure
adhd in children Drug therapy alpha2-adrenergic agonists: Clonidine
Alpha2 agonist
Principal side effects: Somnolence, fatigue, and hypotension
adhd in children: Drug therapy antidepressants: Desipramine, imipramine, and bupropion
Tricyclic antidepressants
Desipramine [Norpramin] and imipramine [Tofranil]
Decrease hyperactivity
Little effect on impulsivity and inattention
Second-line drugs
Bupropion [Wellbutrin]
Can reduce behavioral symptoms
Less effective than stimulants
Poses risk of seizure
Second-line drug
adhd in adults
60% of ADHD cases persist into adulthood
Symptoms
Poor concentration
Stress intolerance
Antisocial behavior
Outbursts of anger
Inability to maintain a routine
Drug therapy
Methylphenidate