CNS Stimulants

Question 1

CNS Stimulant Definition

Answer 1

-any drug that makes the CNS more easily excited

Question 2

General Effects of CNS Stimulants

Answer 2

-Elevated Alertness
-Decreased drowsiness and fatigue (analeptic)
-Increased nervousness, anxiety, and convulsions
(all of these effects become more pronounced with increasing dosages)

Question 3

Basic Methods by Which Stimulants Produce Their Effects (General MOAs)

Answer 3

• Depression (antagonism) of inhibitory transmissions from GABA A receptor
• Enhancement of excitory Neurotransmitter (ACh and DOPA) release
• presynaptic mediation of NT release

Question 4

Therapeutic Uses of CNS Stimulants

Answer 4

-appetite suppression, narcolepsy, ADHD

Question 5

Classes of CNS Stimulants

Answer 5

• Respiratory stimulants
• psychomotor stimulants (sympathomimetics)
• methylxanthines
• nicotine

Question 6

Respiratory Stimulants

Answer 6

doxapram, nikethamide, pentylenetetrazole

• these have a very short duration of action and generally increase the rate and depth of breathing
• SE: CONVULSION

Question 7

Doxapram and nikethamide

Answer 7

• these are true respiratory stimulants
• MOA: blocks GABA A channel. Exact method of increasing tidal volume presumed to be stimulation of chemoreceptors.
• Uses: postanesthetic respiratory depression, combat the respiratory depression of tranquilizer OD, acute hypercapnia as is COPD (FYI this use has been largely replaced by BiPap but could be useful if BiPap contraindicated).
• FYI nikethamide is very rarely used

Question 8

Pentylenetrazole

Answer 8

• classified as a respiratory stimulant but used as a proconvulsant
• Use: to screen latent epileptics and test drugs for antiepileptic properties
• research ongoing for use with Down’s
• SE: seizure

Question 9

Psychomotor Stimulants

Answer 9

ephedrine, amphetamine, methylphenidate, cocaine

• these are sympathomimetics that are chemically similar but have different effects and uses
• increase the concentration of monoamines (primarily dopa, but also NE and serotonin) in the synaptic cleft
• NE and dopa cause the sympathetic effects
• activate the striatum (reward center in brain) which leads to abuse
• Use: weight loss, ADHD, narcolepsy

Question 10

Amphetamine and methamphetamine MOA

Answer 10

• psychomotor stimulant
• MOA: stimulates the release of monoamines by blocking vesicular monoamine transport (this repackages monoamines into vesicles)

Question 11

cocaine and ritalin MOA

Answer 11

• psychomotor stimulant

- MOA: blocks the reuptake of monoamines back into the nerve terminal

Question 12

Anoretics

Answer 12

• amphetamine, phentermine, diethylpropion, d-methamphetamine
• Drugs that are used for obesity
• MOA: Depress appetite by increasing activity in the hypothalamus rather than affecting metabolic rate

Question 13

ADHD drugs

Answer 13

methylphenidate, amphetamine, d-methamphetamine, lisdexamphetamine
-MOA: hypothesized that those with ADHD have higher baseline of psychomotor activity and giving a stimulant somehow reduces this level to normal.

Question 14

lisdexamphetamine

Answer 14

• an ADHD drug

- an amphetamine with a LYSINE group attached which has longer action and less abuse potential

Question 15

Narcolepsy drugs

Answer 15

modafinil,
-used to promote wakefulness with less traditional psychomotor stimulant activities. It is thought that it blocks monoamine reuptake like cocaine without the reward or euphoria
d-amphetamine
-increases alertness

Question 16

Psychomotor stimulants in general

Answer 16

• have good oral absorption
• in addition to therapeutic effects, elevates mood, increases concentration, increases motor and speech activity, diminishes awareness of fatigue, depresses appetite
• OD: hyperreflexia, tremors, convulsion
• fatal hyperthermia

Question 17

Adverse effects of Psychomotor Stimulants

Answer 17

CNS: euphoria, dizziness, tremor, irritability, insomnia, convulsion, hyperthermia, coma
CV: HA, palpitations, arrhythmia, angina
Other: weight loss, psychosis
ADDICTION: High abuse potential with physical and behavioral dependence and tolerance

Question 18

methylxanthines

Answer 18

caffeine, theophylline, and theobromine

• high doses of methylxanthines have teratogenic effects so these should be limited in pregnant pts
• MOA: inhibit phosphodiesterase (limit breakdown) and adenosine (increase release) to raise cAMP levels provide energy and provide bronchodilation

Question 19

caffeine

Answer 19

• the most widely abused drug
• with consistent use caffeine loses its clinical effect and is required just to return to normal energy levels
• withdrawal symptoms HA, fatigue, drowsiness, irritability, nausea, muscle pain
• can lead to mania, panic, and anxiety

Question 20

Physiological Effects of Methylxanthines

Answer 20

CV: increased HR and FOC, arrhythmia, peripheral vasodilation and lower BP short term, risk of cardiac arrest with theophylline
Smooth Muscle: relaxation, bronchodilation, these more pronounced with theophylline
Kidney: Diuresis
Misc: increase prothrombin and factor V

Question 21

Adverse Effects of Methylxanthines

Answer 21

• increased gastric secretions in those with ulcer
• psychic dependence (caffeine)
• allergic reaction (aminophylline)
• NV, diuresis, and dehydration in peds (theophylline)

Question 22

Therapeutic uses of methylxanthines

Answer 22

theophylline: prophyllaxis for chronic asthma and second line treatment for acute asthma
caffeine + ergot alkaloid: migraine

Question 23

General Information About Nicotine

Answer 23

-extremely addictive
-part of the nightshade family and a natural insecticide
CNS: stimulates CNS, increases RR, emesis, tolerance, at large doses convulsion and CNS depression
CV: tachycardia, HBP, miosis, arrhythmia, CV collapse at large doses secondary to CNS depression
-MOA: binds to nicotinic receptors in brain leading to pre and post synaptic release of dopa
-highly active in reward center