CNS stimulants- COMP Flashcards
What agents are considered to be CNS stimulants?
Drugs that stimulate nervous system (CNS) as their primary action are classified as analeptics or convulsants.
Analeptics can increase excitability by either blocking
inhibition or enhancing excitation.
Doxapram is a
Action of ventilation?
centrally acting analeptic that selectively increases minute ventilation by activating the carotid bodies.
Stimulus produced by 1mg/kg of doxapram is
equivalent to that produced by a PaO2 of 38mm Hg acting on the carotid bodies.
What is responsible for increase in minute ventilation associated with doxapram.
An increase in tidal volume, more than an increase in breathing frequency
Which drugs has a large margin of safety
Doxapram
_______is useful in the treatment of ADHD in children.
Methylphenidate
The best-characterized cellular action of methylxanthines is
antagonism of adenosine
Methylxanthines are metabolized
primarily in the liver.
Premature infants and theophylline
Premature infants metabolize theophylline in part to caffeine, and therefore theophylline can be used to
stimulate respirations in neonates with primary apnea of prematurity.
The prominent effect of caffeine is
CNS stimulation.
Caffeine also causes cerebral vasoconstriction and cause
secretion of gastric fluid.
Postdural puncture headache may respond to
300mg of caffeine.
The primary effects of nicotine is
initial stimulation followed by persistent depression
of autonomic ganglia.
CV nicotine
Nicotine also increases heart rate and SBP and evokes peripheral vasoconstriction.
Ingestion of nicotine
Ingestion of cigarette
ENOUGH nicotine in one cigarette can kill a child
Nicotine GI largely due to _____stimulation
Leading to _____and_____
Largely due to parasympathetic stimulation.
Leading to vomiting and diarrhea.
Increase in salivary and bronchial secretions followed by inhibit
Fatal dose of nicotine in adults
Fatal overdose of nicotine in adults is about 60mg.
A GABA analogue that is often administered for treatment of spasticity, due to diseases or injury to the spinal
cord.
Baclofen
KNow DANDROLENE MOA
Produces skeletal muscle relaxation by a direct action
on excitation-contraction coupling, presumably by
decreasing the amount of calcium released from
sarcoplasmic reticulum.
Dandrolene NM
Neuromuscular transmission and electrical properties
of the skeletal muscle cell membranes are not altered
Unlike neuromuscular blocking agents, Dantrolene
cannot
decrease contractile activity by 80%.
Dantrolene in therapeutic doses has little effect on
cardiac and smooth muscle.
Does Dantrolene impair polysynaptic reflexes like
centrally acting agents?
does not impair polysynaptic reflexes like
centrally acting agents.
Absorption from the GI tract and IV injection provides
sustained
dose related concentration in the plasma.
Dandrolene: The IV preparation can cause
phlebitis due to high pH (9.5).
Extravasation of dantrolene can cause
tissue necrosis.
Less than 1% of dantrolene is excreted
unchanged in urine
Elimination half time of dantrolene is.
5-8 hours
Diuresis can also follow dantrolene use, therefore_______ is recommended.
urinary catheter
Dantrolene is useful in the management of patients with
skeletal muscle spasticity due to upper motor neuron lesions.
The maximum oral dose of Dandrolene is
400mg administered in four divided doses.
Dantrolene induced skeletal muscle weakness
often
negates any significant improvement.
__________is effective in the prevention and
treatment of malignant hyperthermia.
Dantrolene is effective in the prevention and
treatment of malignant hyperthermia.
Prophylaxis in malignant hyperthemia-susceptible
patients can be done with
This regimen results in plasma levels
dantrolene 5mg/kg PO in 3 or 4 divided doses every 6 hours, with the last dose 4 hours preoperatively.
>2.8ug/ml at the time of induction.
Alternatively 2.4mg/kg of dantrolene can be given
over 10-30 minutes as
prophylaxis just prior to induction, and for continued protection, one half the dose is repeated in 6 hours.
Dantrolene ________is repeated until symptoms subside or a __________is reached.
2mg/kg IV; cumulative dose of 10mg/Kg
MH first sign
Masseter rigidity (not responsding to NMB)
Therefore triggering drugs must be avoided even when
dantrolene prophylaxis is used.
Most common side effect is
skeletal muscle weakness that may be sufficient to interfere with adequate ventilation of the lungs or prevent
aspiration.
Class of methylxanthines
Caffeine
Theophylline
Theobromine
Apnea of prematurity treated with
Caffeine
Structurally related to TCA is
Cyclobenzaprine (flexeril)
Should not be given with MAOI
Dandrolene can lead to
Uterine Atony
