Medications for anesthesia, neurological conditions, and psychiatric conditions Flashcards
Anesthetics, Sedative-Hypnotics and analytics, Affective Disorders and Psychiatric Disorders, Anti-epileptics, Drugs for PD, Drugs for MS
Distinguish difference between general and local anesthetics
General is fully body with a patient unconscious whereas local is injected into one area and the patient is still awake
What is induction stage I of general anesthesia
Analgesia:
- pt loses somatic sensation but is still conscious and aware of what is happening
What is induction stage II of general anesthesia
Excitement (delirium):
- pt unconscious but agitated/restless
- want to move quickly thru this to stage III
List different types of general anesthesia and adjuvant medications used during anesthesia
- Pre-op Meds for relax and reduce post op N/V
- Neuromuscular blockers (nondepol and depolarizing)
List some IV anesthetics
- Barbiturates
- Benzodiazepines
- Opioid Analgesics
- ketamine
[- propofol - etomidate
- dexmedetomidine]
How do barbiturates work
CNS depressant to decrease anxiety and facilitate induction of anesthesia used in IV anesthetics
How do benzodiazepines work
CNS depressant to decrease anxiety and tension and provide sedation and amnesia used in IV anesthetics
How do opioid analgesics work
They provide analgesia, antianxiety and sedative effects used in IV anesthetics
How does ketamine work
It produces a dissociative anesthesia that does not cause respiratory or cardiac issues but can cause hallucinations and other rxns during recovery used in IV anesthetics
What is dexmedetomidine
It is a newer IV anesthetic used mostly for ST ICU to stimulate certain alpha receptors in the brain
What is the pharmacokinetics of general anesthetics
- IV metabolized in liver and eliminated in kidneys
- inhaled: metabolized and eliminated in the lungs
What is a concern w/anesthetic if a person has liver or lung disease
It will take longer for it to be eliminated causing longer periods of confusion, disorientation and lethargy
Age concerns w/pharmacokinetics of general anesthesia
- older adults need smaller doses
- difficult w/children since their organs are immature and they have small body masses
What is the mechanism of action of general anesthesia
- Increases inhibition in the CNS by exciting GABA and glycine
- Decreases excitation by acting on K+, ACh, NMDA and opioids
In general, how do anesthetics exert their effects?
By binding to receptors in the CNS
What are the types of pre-operative meds given w/general anesthesia
- sedatives
- anti N/V
- decrease bronchial secretions
- dec gastric acidity (help w/N/V)
- post-op pain (opioids and steroids)
What are neuromuscular blockers
Adjuvants to general anesthesia that increase skeletal mm paralysis to allow for safe surgery
What are the side effects of neuromuscular blockers
tachycardia, increased histamine release, hyperkalemia, residual mm pain and weakness, anaphylaxis
Nondepolarizing blockers vs depolarizing blockers (neruomuscular)
Nondepol last longer by acting as competitive antagonists of post synaptic recetor ro prevent ACh from binding whereas depol is more short term since it acts like ACh and binds and stimulates receptor to depol it so it cant contract
What are the rehab concerns of general anesthesia
- lingering effects (woozy, confused) esp in older adults
- bronchial secretions in lungs
- LT effects on mem and cognition in older adults and those w/cognitive disorders
What is the goal of local anesthesia
To block afferent NT along the periph nerve
What are some advantages of local anesthesia
- rapid recovery
- lack of residual effects
- does not interfere w/CV, pulm, or renal function
- beneficial for childbirth
What are some disadvantages of local anesthetics
- takes longer to achieve effects and there is a risk that analgesia will be incomplete or insufficient
What are the two main categories of local anesthetics
esters and amides
What drug is often co-administered w/local anesthetics and why
A vasoconstrictor so that the anesthetic does not travel out of the target tissue
What is the pharmacokinetics of local anesthetics
- metabolized in liver and blood stream
- excreted in the kidneys
what are the clinical uses of anesthesia (list)
topical transdermal infiltration anesthesia peripheral nerve block central nerve block sympathetic block
What is topical anesthetic
A local anesthetic applied directly to the skin surface, mucous membrane or cornea to allow for symptomatic relief of minor irritations and injury and can reduce pain before minor surgical procedures
What is transdermal anesthetic
A local anesthetic applied to the surface of the skin via patches that can be enhanced w/ionto or phonophoresis to treat tendons, bursae or soft tissue
What is infiltration anesthetic
A local anesthetic where the drug is injected directly into the select tissue and diffuses to sensory nerve endings w/in that tissue –> good for suturing lacerations
What is peripheral nerve block anesthetic
a local anesthetic injected close to the nerve trunk of a peripheral nerve so that transmission is interrupted-> can sometimes be a continuous nerve block where they insert a catheter near the nerve
What is central nerve block anesthetic
A local anesthetic that is injected w/in the spaces surrounding the SC or win the SC but there is a higher risk of Neurotoxicity
What is sympathetic blockade anesthetic
a local anesthetic that selectively interrupts sympathetic efferent DC w/the goal to disrupt outgoing sympathetic signals
What is sympathetic blockade anesthetic useful for
complex regional pain syndrome (CRPS)
What is the mechanism of action of local anesthetics
Disrupt the Na+ channels along the periph nerve so that the message cannot be transferred down further
What are the systemic effects of local anesthesia
CNS toxicity (ringing in ears, agitation, dec sensation) or cardiac toxicity (bradycardia, fatigue, dizziness)
What are the rehab concerns of local anesthetics
- keep a lookout for transdermal patches as you don’t want to heat it (will infuse too fast)
- if continuous nerve block will lack sensation and possible motor control
What are sedative hypnotics
Drugs that promote sleep, esp in acute or ST situations
What are the two categories of sedative hypnotics
Benzodiazepines and non-benzodiazepines
List some other uses of sedative-hypnotics
- anti-anxiety
- sedation and amnesia
- seizure treatment
- control of withdrawal
- mm relax
What are affective disorders
characterized by marked disturbances in a person’s mood - very common in society
What are two types of affective disorders
Depression
Bipolar Disorder
What is depression
General dysphoric mood and lack of interest in previously pleasurable activities that can lead to recurrent thoughts of death and suicide
How can depression be classified
- type
- duration
- intensity of symptoms
What are the 3 factors that contribute to depression
Environmental, biochemical, and genetic
What is the pathophysiology of depression
Disturbance in amine neurotransmitters (serotonin, norepinephrine, and DA)
What are the amine NTs
- serotonin
- norepinephrine
- dopamine
List the two theories of how the pathology of depression occurs
Receptor sensitivity theory
neurogenesis theory
What is the receptor sensitivity theory
- Depression causes a supersensitivity to amine NT
- Antidepressants enhance the stimulation of pre and postsynaptic receptors
- Receptor sensitivity decreases to a more balanced level (takes about 2-3 weeks)
What is the neurogenesis theory
- When people are depressed, they grow less neurons and receptors
- Drugs promote regrowth so there is increased influences of the amines
List some anti-depressant drugs
- SSRI (selective serotonin reuptake inhibitors)
- SNRI (serotonin-norepinephrine reuptake inhibitors)
- tricyclics
- MAOI
What are Selective Serotonin Reuptake Inhibitors (SSRIs)
Antidepressant that block enzyme responsible for the re-uptake of serotonin back into the presynaptic terminal so that more remain in the synaptic cleft –> people are happier
What is the most common antidepressant
SSRI
What are Serotonin-norepinephrine reuptake inhibitors (SNRI)
Antidepressant that decreases serotonin and norepinephrine reuptake without effecting dopamine synapses
- also treat pain conditions (fibromyalgia, chronic, etc)
What are the adverse effects of SSRI and SNRI
- GI: N/V, diarrhea, constipation
- serotonin syndrome
What is serotonin syndrome
a serious and potentially fatal condition of elevated serotonin that causes sweating, agitation, restless, shivering, tachycardia, and neuromuscular excitability that can lead to coma and death
What are tricyclics
Antidepressants that block the reuptake of amine NTs into the presynaptic terminal nonselectively (leading to more interactants with other drugs)
Who are tricyclics used for
Those who have failed w/other antidepressant treatments
What are some of the adverse events from tricyclics
- sedation
- arrhythmias and OH
- increase in seizure
- anticholinergic prop (block ACh to cause confusion and delirium)
Which antidepressant has the highest potential for fatal OD
Tricyclics because of the risk of cardiac arrhtymias
What is Monoamine oxidase
An enzyme in the CNS that breaks down NT in the synapses
What are monoamine oxidase inhibitors (MAOI)
Antidepressants that inhibit MAO allowing more NTs to remain in the amine synaptic cleft, which can lead to changes in receptor sensitivity - BUT have a lot of interactions with food and other drugs
What are some of the adverse events of MAOI
- They produce CNS excitation (restlessness, irritability)
- increase BP including hypertensive crisis
- central and peripheral anticholinergic effects
- interactions w/foods and tyramine
What are other mechanisms for antidepressants
- block serotonin receptors and inhibit serotonin reuptake
- DA and norepinephrine reuptake inhibitor
What are the pharmacokinetics of antidepressants
- administered orally
- cross BBB to exert effects
- metabolized in liver
- eliminated in the kidneys
Can antidepressants treat chronic pain
Yes BUT only Cymbalta is FDA approved to treat it
- tricyclics have been used
- SSRI & SNRI are used in fibromyalgia and neuropathies
What is Bipolar Disorder
An affective disorder characterized by mood swings from one extreme (mania) to the other (depression) - but the exact cause is unknown
What is Lithium (Li+)
A monovalent cation from the alkali metal group of the periodic table that competes w/other cations (Na+, K+, and Ca+) and has neuroprotective effects and limits neuronal damage
What are the pharmacokinetics of lithium
- It is administered orally and readily absorbed in GI tract
- LITHIUM IS NOT METABOLIZED
- whole drug is eliminated by excretion in urine
When is a higher dose of lithium needed in bipolar disorder
In an acute mania
What are some adverse effects of lithium
Lithium toxicity
- Early on mild symptoms, but can progress (in the: CNS, GI, CV, Renal)
What are drugs that treat bipolar disorder
- Lithium
- Anti-seizure meds (stabilize mood and limit manic symptoms)
- Antipsychotic meds (anti-mania)
Which affective disorder medications cause sedation
Tricyclics and lithium
What is the most common side effect of affective disorders
OH
What are the rehab concerns of affective disorders
- other non-pharmacological treatments can be helpful as well
- exercise increases brain derived neurotropic factor - which is good for brain health
- drug therapy can increase depression
What is the main way affective disorder medications exert their effects
By modifying synaptic transmission and neuronal growth and function in the CNS
What is psychosis
A term that describes a more severe form of mental illness that is characterized by marked thought disturbance and an impaired perception of reality
What is the most common type of psychosis
Schizophrenia
What are neuroleptics and why are the important?
Antipsychotic drugs that treat the disorder instead of simply sedating the patient (like before they came out)
What occurs in schizophrenia
- (primarily) Overactivity of DA pathways
- Increased serotonin
- defect in GABA
- decreased sensitivity to ACh
What is the mechanism of action of first generation antipsychotics
Strong dopamine antagonists (D2 receptor)
- BUT can increase incidence of movement disorders and motor side-effects
What is the mechanism of action of second generation antipsychotics
Weak antagonists at the D2 receptor but strong antagonists of serotonin
- w/less side effects than the 1st gen
What are other uses of antipsychotics
- decrease N/V
- control agitation and aggression in Alzheimer’s patients
- combo w/lithium in acute mania for bipolar
What are the pharmacokinetics of antipsychotics
- metabolized in liver
(over t can lead to enzyme induction//less effective) - excreted in kidneys
When are higher doses of antipsychotics given
During acute episodes w/lower maintenance doses
What are some problems and adverse effects of antipsychotics
- extrapyramidal symptoms (PD like)
tardive dyskinesia, akathisia, dyskinesia - nonmotor effects
What is tardive dyskinesia
involuntary and fragmented mvmts, particularly in the mouth, tongue, and jaw that are often irreversible as a side effect of antipsychotic medicatiosn
How does pseudoparkinsonism develop w/antipsychotic use
they block DA receptors in the BG leading to resting tremor, bradykinesia, and rigidity
What is akathisia
Sensations of motor restlessness caused by an inability to sit or lie still that can be improved w/lower doses of antipsychotics
What is neuroleptic malignant syndrome (NMS)
Lack of DA leading to catatonia, stupor, rigidity, tremors, and fever and can lead to death if untreated
What are the metabolic effects of antipsychotics
mostly seen w/atypical antipsychotics
- weight gain
- increased plasma lipids
T or F: Sedation is beneficial in antipsychotic medications
FALSE
What are some anticholinergic effects (seen w/antipsychotics)
- blurred vision
- dry mouth
- constipation
- urinary retention
T or F: OH is more of a long-term concern with anti-psychotics
False - it occurs only in the first few days of taking a medication
What are some rehab concerns of antipsychotics
- be on the alert for new extrapyramidal symptoms and report to MD
What is the primary means of controlling epilepsy and seizures
Drug therapy
What happens in epilepsy
some cerebral neurons are hyperexcitable and discharge spontaneously causing seizures
What are the goals of antiseizure drugs?
- Increase the activity of CNS inhibitory neurons
- Decrease the activity of CNS excitatory neurons
- Stabilize Na+/Ca+ channels
- Suppress excitability of neurons that initiate the seizures
What are some first gen antiseizure drugs
- barbiturates
- benzodiazepines
- hydantoins
- iminostilbenes
- succinimides
- valproates
why use second gen antiseizure drugs
Better pharmacokinetic profile w/milder side effects allowing for better LT use
What are some second gen antiseizure drugs
gabapentin
pregabalin
lacosamide
How do anti-seizure meds treat chronic pain
Reduce excitation in pathway responsible for chronic pain –> most effective in neuropathic pain
What are the pharmacokinetics of anti-seizure meds
- CAN cross BBB
- metabolized in liver
- excreted in kidneys
What are some side effects of anti-seizure meds
sedation tolerance ataxia GI confusion dizzy cardiac arrhythmias
How are seizures categorized
according to clinical and electrophysiological manifestation that occur during the seizure
T or F:
Some people can be withdrawn from their antiseizure meds if specific criteria has been met
True - under medical supervision
What is PD
A movement disorder from slow, progressive degeneration of certain DA-secreting neurons in the BG causing resting tremor, bradykinesia, rigidity, and postural instability
Normal vs Parkinsonism: what chemical is more dominant in the brain?
Normal: DA
PD: ACh
List some drugs used in PD
Carbidopa (DOPA decarboxylase inhibitor) Levadopa (Dopamine precursor) DA Receptor agonists MAO inhibitors COMT inhibitors Antimuscarinic Agents (Anticholinergic Agents) Amatadine (symmetrel)
How does Levadopa work
It is a DA precursor that is converted to DA after crossing the BBB that then improves all symptoms of PD
T or F: Ldopa is equally effective over time
False - it becomes less effective due to side effects
What converts Ldopa to dopamine
Dopa decarboxylase
What is carbidopa
A peripheral decarboxylase inhibitor that is given w/Ldopa to prevent early conversion to DA in the periphery
What are the possible Carbidopa-Levidopa ratios?
1:4 or 1:10
What are the adverse effects of Ldopa
- OH
- Psychotic symptoms
- GI problems
- dyskinesias
What is the On-Off phenomenon and why is this important
- OFF = effectiveness of Ldopa decreases –> worsening symptoms
ON = remission of symptoms after taking dose of Ldopa
Dosing schedule to maximize On time
List the fluctuations seen w/taking LDopa
On-Off
End-of-dose akinesia
Freezing gait
What is end-of-dose akinesia and how to we fix it
Drug’s effectiveness wears off prior to next dose.
- give smaller doses more frequently
What do DA receptor agonists do and side effect
Smooth out the On-Off phenomenon, given alone or w/levadopa or antimusc drugs BUT may cause impulse control disorders
What are some DA receptor agonists
bromocriptine (Parlodel)
ropinirole (Requip)
What do MAO-B inhibitors do
As an adjunct to Ldopa, it inhibits MAO-B so that DA is not metabolized in the BG and stays active for a longer time
What do COMT Inhibitors do
As an adjunct to Ldopa-Cdopa to inhibit COMT so that Ldopa is not broken down in the periphery so more can reach the brain
What do antimuscarinic drugs do
They act as antag at cholinergic muscarinic receptors to inhibit excessive ACh influence on cells in the striatum to improve tremor and rigidity (NOT BRADYKINESIA)
What are the side effects of antimuscarinic drugs
PERIPHERAL
- sedation
- urinary retention
- constipation
- confusion
What is amantadine (symmetrel)
An antagonist at glutamate NMDA receptors to create anticholinergic actions that either increases syn/releas of DA or inhibits its reuptake
Which DA drug is also an anti-viral agent
amantadine (Symmetrel)
When should you initiate pharmacotherapy for PD patients?
No clear answer
What are the rehab concerns of drug therapy in PD
- Monitor BP since OH is a common side effect
What is MS
focal areas of demyelination w/reactive gliosis in the white matter (Brain, SC, optic nerves) w/an autoimmune component
What is the presentation of MS
- wewakness, numbness, tingling, spasticity
- unsteadiness, dyscoord
- visual changes
- sphincter disturbances
What do MS meds seek to do?
- reduce frequency of exacerbations
- slow disease progression
- treat acute exacerbations
- symptomatic treatment
What meds reduce frequency of exacerbations in MS
- Interferons (immune enhancers)
- Immunomodulators
- Antineoplatsics/Antimetabolites
What drugs slow disease progression in MS
Monocolonal antibody
Sphingosine 1-phosphate receptor modulator
What drugs are used in an acute exacerbation in MS
Corticosteroids