Block 3 Drugs Flashcards
parenterally administered anesthetic barbiturate quick action, short duration, long half-life
sodium thiopental activates GABA A receptors
barbiturate side effects
CNS depression (can be good) cardiovascular (vasodilation, venodilation) respiratory depression (must intubate)
parenteral general anesthetic used to induce & maintain anesthesia antiemetic 3.5 hr half life
propoforl GABA A mechanism
propofol side effects
pain on injection (inject w/ lidocaine into larger vein) initial excitation on induction CV: severe BP reduction AND decr myocardial contractility respiratory depression (more than thiopental)
used to induce anesthesia in patients at risk for hypotension
etomidate
etomidate side effects
lots of pain w/ injection, myoclonus nausea & vomiting suppression of adrenocortical response to stress only used w/ patients w/ hemodynamic problems CNS same as thiopental CV FAR less than thiopental Respiratory less than thiopental
produces dissociative anesthesia analgesia, amnesia doesn’t affect respiration, bronchodilator
ketamine NMDA receptor antagonist
ketamine side effects
nystagmus, salivation, lacrimation, spontaneous movement/increased muscle tone increase cerebral blood flow → increased intracranial pressure emergence delirium (less in kids) hypertension
ketamine’s usefulness
patients with bronchospasm kids for short, painful procedures
short-acting benzodiazepine GABA A activator use alone for conscious sedation, short procedures induction agent (less so), decreases anxiety
midazolam
midazolam pharmacokinetics
slower induction time, longer duration than thiopental metabolized to active metabolite
midazolam side effects
resp depression/arrest (esp IV) use w/ caution in patients w/ neuromuscular disease, parkinsons’, bipolar CV similar to thiopental
commonalities of inhalation general anesthetics
low therapeutic indices gaseous or volatile
factors that affect induction with a gaseous anesthetic
anesthetic concentration in inspired air pulmonary ventilation pulmonary blood flow arteriovenous concentration gradient
anesthesia achieved when?
when brain partial pressure is equal to MAC
moderate blood:gas PC, not quick recovery excreted unchanged into expired air uses: inhaled induces and especially maintains anesthesia, used with NO
isoflurane
isoflurane side effects
respiratory: airway irritant, coughing, decreases tidal vol, increase resp rate, depresses respiration, increases PaCO2 cardio: myocardial depression, decreased BP, arrhythmias, cerebral vessel vasodilation → increased intracranial pressure
volatile and RT; low solubility in blood, rapid induction and recovery; excreted unchanged used in outpatient surgeries, maintenance not induction, causes skeletal relaxation
desflurane
desflurane side effects
CV same as isoflurane resp: worse as irritant, bronchospasm
low blood:gas PC; 5% metabolized to fluoride ion in liver; degraded to compound A by absorbants inpatient and outpatient; induce and maintain; kids and adults; not resp irritant
sevoflurane
sevoflurane side effects
similar to isoflurane, not as much respiratory depression
rapid equilibration; used to enhance induction; weak anesthetic, don’t get MAC sedation, analgesia; use with others to reduce dose
nitrous oxide when emerging, use 100% O2
nitrous oxide side effects
CI w/ pneumothorax; negative inotrope (decr HR); sympathomimetic (helps increase HR); minimal resp effects besides O2 dilution; abuse liability
injection of local anesthetic around individual nerves/nerve plexuses
nerve block anesthesia
local anesthesia mechanism of action
act directly on nerve cells to block ability to conduct impulses bind directly to voltage-dependent sodium channel higher affinity for inactive channel than unopened channel
co-administration of local anesthetic with vasoconstrictors (eg epinephrine)
decrease rate of absorption into circulation, increasing duration of anesthesia less potential for systemic toxicity
order of CNS toxicity for local anesthetics
CNS stimulation first then CNS depression at higher doses death due to respiratory depression
cardiovascular toxicity of local anesthetics
general depression of CV after CNS effects: decreased contractility, decreased BP, decreased rate of conduction (arrhthmias), arteriolar vasodilation cardiac arrest
how are ester local anesthetics inactivated?
by plasma esterases
how are amide local anesthetics metabolized?
by the liver
local anesthetic; blocks pre-synaptic NE uptake potent vasoconstrictor topical anesthesis of upper respiratory tract
cocaine
short acting, synthetic local anesthetic low potency, slow onset, short duration
procaine
long acting, more potent, longer duration ester anesthetic spinal anesthesia, topical and opthalmic preparations
tetracaine
low water solubility so low toxicity applied to wounds and ulcerated surfaces
benzocaine
amide, intermediate duration of action; faster, longer lasting and more extensive anesthesia often used with vasoconstrictors
lidocaine
long acting amide, prolonged anesthesia, more sensory than motor block, more cardiotoxic
bupivicaine
long acting amide, S-enantiomer, less cardiotoxicity, motor sparing epidural and regional anesthesia
ropivacaine
amides
metabolized by liver not associated with allergic reactions
esters
metabolized by plasma cholinesterases rare allergic reactions
neuropsych drugs pt 1
amitriptyline clomipramine fluoxetine sertraline buproprion mirtazapine duloxetine phenelzine chlorpromazine clozapine thioridazine fluphenazine haloperidol olanzapine risperidone quetiapine aripiprazole
Which drugs are used in the treatment of depressive disorders?
SSRIs, SNRIs, Atypical drugs, Tricyclic antidepressants, MAOIs
5-HT uptake inhibitors
SSRIs- fluoxetine, sertraline
SSRI side effects
nausea, insomnia, and sexual dysfunction no food rxns, but dangerous “serotonin reaction” (hyperthermia, muscle rigidity, CV collapse) can occur if given with MAOIs
Do SSRIs have fewer or more adverse effects than TCAs and MAOIs?
less, so overdose risk is reduced
Symptoms of SSRI withdrawal
-dizziness, light-headedness, vertigo or feeling faint, shock-like sensation, paresthesia, anxiety, diarrhea, fatigue, gait instability, headache, insomnia, irritability, nausea or vomiting, tremor, visual disturbances -symptoms begin within 1-7 days after stopping an SSRI
SSRI approved uses
Major Depression OCD Panic disorder Social Anxiety Disorder PTSD Generalized Anxiety disorder PMS (now PDD) Hot flashes associated with menopause
effects on drug metabolism, long half-life active metabolite (7 days or more). now available as a sustained release product. used to treat PMS
fluoxetine
used to treat OCD, PTSD, Panic attacks; less effects on metabolism than fluoxetine, shorter half life.
sertraline
block both 5-HT and NE reuptake, side effect profile is more SSRI-like than TCA-like
SNRI drugs
12-18 hr half-life. also approved for neuropathic pain syndromes, fibromyalgia, back pain, and osteoarthritis pain. What is the drug and which patients to do you have to use caution with?
duloxetine -use caution in patients with liver disease
neuropsych drugs pt 1
amitriptyline clompiramine fluoxetine sertraline buproprion mirtazapine duloxetine phenelzine chlorpromazine clozapine thioridazine fluphenazine haloperidol olanzapine risperidone quetiapine aripiprazole
drugs without typical TCA structure of SSRI or SNRI action. May or may not block catecholamine uptake
Atypical antidepressants
weakly blocks NE and dopamine uptake. No weight gain or sexual dysfunction. what is the drug and what is it also approved for?
bupropion -also approved for nicotine withdrawal and seasonal affective disorder
blocks presynaptic alpha2 receptors in the brain. increases appetite
mirtazapine -good for AIDS patients with AIDS wasting syndrome
blocks NE and 5-HT reuptake; first highly effective drugs for the treatment of depression; now used secondarily to SSRIs and other newer compounds
tricyclic antidepressants
pharmacokinetics of TCAs
rapidly absorbed after parenteral or oral administration; relatively high concentrations are found in the brain and heart.
demethylated to active metabolites which are used as drugs themselves; long plasma half-life (8-100 hrs)
amitriptyline
side effects of TCAs
sedation cardiac abnormalities (due to anticholinergic effects and increased NE concentrations–>palpitations, tachycardia, and arrhythmias) overdoses: acute toxicity (symptoms include hyperpyrexia, hyper- or hypotension, seizures, coma, and cardiac conduction defects)
side effects of TCAs
sedation cardiac abnormalities (due to anticholinergic effects and increased NE concentrations–>palpitations, tachycardia, and arrhythmias) overdoses: acute toxicity (symptoms include hyperpyrexia, hyper- or hypotension, seizures, coma, and cardiac conduction
contraindications for TCAs?
recent MIs
TCAs and drug interactions?
TCAs effect absorption and metabolism of other drugs TCAs block guanethidine uptake sympathomimetic drugs; particularly indirect acting agents
therapeutic uses of TCAs
major depressive disorder (3rd choice) enuresis in childhood- imipramine chronic pain (neuropathic pain that opiates do not handle as well)- amitriptyline OCD- clomipramine and SSRIs
non-selective MAOI
phenelzine
produces mood elevation in depressed patients; may progress to hypomania particularly in bipolar disease; corrects sleep disorders in depressed patients; may produce stimulation in normals; antidepressant action takes about 2 weeks
MAOIs
symptoms of actue toxicity of MAOIs
agitation, hallucinations, hyperpyrexia, convulsions, and changes in bp
what do you have to restrict in patients on MAOIs?
dietary intake of tyramine
therapeutic uses of MAOIs
major depression (not first drug of choice, however) narcolepsy
other treatments for depression
electroconvulsive shock therapy (ECT) transcranial magnetic stimulation (TMS) cortical and subcortical electrical stimulation (still experimental)
nonspecific blockers of NE and 5-HT reuptake
amitriptyline
selective serotonin reuptake inhibitors (SSRIs)
fluoxetine, sertraline