Final Exam Flashcards
Levothyroxine (Synthroid, Levoxyl)
Given for the treatment of hypothyroidism -Synthetic T4; Identical to naturally occurring thyroid hormone
-Converted to T3
Pharmacokinetics
- Given PO & well absorbed in empty stomach (30-60 min. prior to breakfast) EMPTY STOMACH needed*
- IV form available
- Highly protein bound
- Once per day dosing
- Takes about 1 month to reach plateau
-Since thyroid hormone occurs naturally in the body, almost anyone can take levothyroxine.
ο Pregnancy Category A (SAFE in pregnancy). The drug does pass in breast milk but is considered safe to use.
Adverse Effects
-Thyrotoxicosis- too much T3 and T4 (thyroid storm)
-Osteoporosis
-Atrial fibrillation
Absorption decreased by:
- Calcium supplements
- Antacids
- ron
- Cholesterol binding agents
- Food – esp. important to avoid infant soy formula, cotton seed meal, walnuts and high fiber foods (decreases absorption)
Drugs that accelerate metabolism of levothyroxine:
- Phenytoin, carbamazepine, rifampin
- Warfarin
- Levothyroxine accelerates the degradation of vit K dependent clotting factors
- There increased effects of warfarin
- Catecholamines
- Thryroid hormones increase the responsiveness to catecholamines…use cautiously
- Epinephrine, dopamine, dobutamine
- Insulin and digoxin
Levothyroxine can increase the requirements for both of these drugs
Nursing Implications:
- Monitor height and development in infants and children
- Teach to take on empty stomach
- Frequent follow up and lab monitoring
- Different brands of levothyroxine may NOT work the same
- Blood work after 6 weeks
Methimazole (Tapazole)
Treatment for Hyperthyroidism
First line drug
MOA:
-Inhibits thyroid hormone synthesis
- Does not destroy existing stores of thyroid hormone
- Can take 3-12 weeks to achieve a euthyroid state
- Safer than PTU
- PO
Applications:
- Graves’ disease
- Adjunct to radiation therapy
- Suppress thyroid synthesis in preparation for thyroidectomy
- Avoid with pregnant women or breast feeding
Adverse Effects:
- Agranulocytosis most serious and dangerous toxicity- more prone to getting sick
- Dramatically reduces granuolcytes (type of WBC) needed to fight infection
Teach patient to Report sore throat, fever immediately!
Propylthiouracil (PTU)
Indicated for hyperthyroidism
MOA: Decreases the synthesis of thyroid hormones
-Can also cause agranulocytosis
Different from Tapazole in that :-Causes severe liver injury
- Requires 2-3 doses per day
- Safer in pregnancy and in breast milk
- Blocks conversion of T4 to T3*
Indicated for:
- Pregnant women in 1st trimester
- breast-feeding women
- Pts with thyroid storm
- Pts intolerant of Tapazole
- Can treat at a higher dose with PTU than tapazole
Beta Blockers and Hypothyroidism
ο Beta Blockers also have a role in treatment of hyperthyroidism. To help decrease the HR while we are waiting for the drug to treat the actual condition to kick in. For some people they stay on it at a low dose
ο Suppress tachycardia and other symptoms of Graves’ disease
ο Benefits derive from beta-adrenergic blockade, not from reducing levels of T3 or T4
- Also my be used in thyrotoxic crisis
- Contraindicated in pts with asthma*
Beta Blockers- OLOL
Propranolol(Inderal)
Nonselectivebetaadrenergicantagonist (Beta1 andbeta2)
o ↓ HR, ↓force of ventricular contraction and slow impulse conduction through the AV node, suppress secretion ofrenin (Beta1)
o Bronchoconstriction (Beta2)
o Inhibits glycogenolysis (Beta2)
♣ Breakdown of glycogen to glucose
♣ Most detrimental to diabetics
o Lipid soluble – easily crosses membranes
o Well absorbed
o Widely distributed
o Hepatic metabolism
o Excreted in the urine
Drug interactions:
-Calcium channel blockers- decreases the calcium from allowing contraction so withbetablockers it decreases the force of the heart as well. So together it will make it even harder for the muscle to contract.Typicallynot prescribed together because can cause HF
-Insulin- more vigilant about screening for hypoglycemia
Metoprolol(Lopressor)
Cardioselective(Beta1 only)- only impactsbeta1receptors.
Pt with emphysema can take this
Therapeutic Uses: o HTN, heartfailure andMI • Hepatic metabolism • Renal excretion • Adverse Effects o Bradycardia, ↓ CO, AV block, rebound tachycardia with abrupt discontinuation
Local Anesthetics
Reversibly block all nerve impulses by disrupting permeability to sodium during action potential.
-Suppress impulse conduction along axons
- Conduction blocked only in neurons near the site of administration
- Sensations are blocked at different rates: pain first, followed by cold, warmth, touch, and deep pressure
-Not limited to sensory, may affect motor
Onset and duration affected by… Ð Molecular size Ð Lipid solubility Ð Degree of ionization Ð Regional blood flow- makes sure that the anesthetic gets good absorption
Frequently combined with epinephrine:
- Vasoconstrictor decreases local blood flow and delays systemic absorption of the anesthetic
- Decreases toxicity risk: less anesthetic used and slower absorption
Adverse Effects:
-Central Nervous System:
CNS agitation followed by depression
Cardiovascular system:
- Heart cause suppression of excitability
- Vessels causes vasodilation
Allergic reactions
-Varied
Labor and delivery
-Prolong labor by decreasing uterine contractility and maternal expulsion effort; can cause bradycardia and CNS depression in the neonate
Lidocaine
- local anesthetic
- Administered topically and by injection
- Also used as an antidysrhythmic agent
- Duration of action depends on strength
- Addition of epinephrine
- Risk of systemic toxicity
Lidocaine continued
Tetracaine is a topical lidocaine
- Surface anesthesia
- Pain, itching, soreness caused by infections, thermal burns, bruises, abrasions, plant poisonings, insect bites
Used in mucus membranes
-Risk for systemic toxicity
Systemic absorption determined by…
- Amount applied
- Skin condition
- Skin temperature
Administration:
- Smallest amount possible
- Avoid application to large areas
- Avoid application to broken skin
- Avoid strenuous exercise
- Avoid wrapping the site
- Avoid heating the site
Injection
- Resuscitation equipment should be immediately available
- Maintain IV line for rapid treatment of toxicity
- Aspirate to ensure not administering in a vessel
Infiltration Anesthesia
- Injected directly into area of surgery or manipulation
- If combined with epinephrine
- No end artery areas
- No fingers, toes, noses, ears, or penis
Nerve Block
-Achieved by injecting a local anesthetic into or near nerves that supply the surgical field, but at a site distant from the field itself
-Local Anesthetics
Injection
Intravenous Regional Anesthesia
-Used to anesthetize the extremities, but not the entire limb
-Anesthesia is obtained by injection into a distal vein of an arm or leg
-Tourniquet is applied to the limb to prevent anesthetic from entering the systemic –Local Anesthetics
Injection
Epidural
- Achieved by injecting a local anesthetic into the epidural space
- Administration by bolus or by continuous infusion
- Diffusion blocks conduction in nerve roots and in the spinal cord itself
- Significant systemic absorption can occur
If given to pregnant mothers- Monitor for neonatal depression
General Anesthetics
Analgesia and Anesthesia
- Analgesics are drugs that relieve pain without causing loss of consciousness.
- Anesthetics are drugs that produce unconsciousness & insensitivity to painful stimuli
- Produce unconsciousness and lack of responsiveness to all painful stimuli
- Inhalation agents
- Parenteral agents
Balanced Anesthesia
Use of a combination of drugs to accomplish what we cannot achieve with an inhalation anesthetic alone
Compensates for lack of an ideal inhalation anesthetic
Allows for full general anesthesia at lower (safer) doses
General Anesthetics Inhalation Agents Minimal Alveolar Concentration -The amount of anesthetic inspired air must contain to produce anesthesia -Low MAC -High MAC
Inhalation Agents Uptake: -MAC -Pulmonary ventilation -Solubility of anesthetic in blood -Blood flow through the lungs
Distribution:
- Determined by regional blood flow
- Levels rise rapidly in brain, kidney, heart, and liver
Elimination
- Via lungs
- Anesthesia levels in the CNS decline more rapidly than in other tissues
Patients can waken from anesthesia before all anesthetic has left the body
Adverse Effects of General Anesthesia
- Respiratory depression
- Cardiac depression- esp with someone who has cardiac issues
Increased risk with:
- Chronic respiratory problems
- Cardiac problems
- Significant obesity
Malignant hyperthermia
- Fatal reaction, genetic predisposition
- Muscle rigidity, T up to 43 degrees C
Treatment: dantrolene sodium
Aspiration of gastric contents
- Hepatotoxicity
- Toxicity to operating room personnel
- Headache, reduced alertness, spontaneous abortion
- Ensure proper venting of gases
General Anesthetics
Inhalation Agents
Volatile liquids “–fluranes” EX: Isoflurane, enflurane, desflurane, sevoflurane -Rapid induction time -Easy to adjust -Rapid emergent time -Causes hypotension, bradycardia
Gases: Nitrous oxide
- “laughing gas”
- Adjunct in balanced anesthesia
- Can not produce surgical anesthesia alone
- *Powerful analgesic, weak anesthetic
Adjuncts to in halation anesthesia ( pre-anesthesia/post anesthesia medications)
Pre-anesthetic meds: Benzodiazepines
- Reduce anxiety and promote amnesia
- Given to induce anesthesia or for conscious sedation
ex: Midazolam (Versed)
Opioids
-Pain relief, cough suppressant
Preanesthetic Medications
- Alpha 2-adrenergic agonists
- Anticholinergic agents
- Neuromuscular blocking agents
Postanesthetic Medications
- Analgesics
- Antiemetics
- Muscarinic Agonists
Intravenous anesthetics
Propofol (Diprivan)
- Promotes release of GABA
- General CNS depression
- Induction and maintenance of GA
Sedation for mechanically ventilated patients, radiation therapy, diagnostic procedures
- IV administration
- Unconsciousness in less than 60 seconds
- Duration is 3-5 minutes
- Continuous infusion is needed for extended sedation
Adverse Effects
- Respiratory depression/apnea
- Hypotension
- Risk of bacterial infection
- Pain at the site of infusion
High abuse risk
Opioids
MOA:
Opioid Receptors:
Mu and Kappa
Mu- opioids activate these
-Analgesia, respiratory depression, sedation, euphoria, physical dependence, and decreased GI motility
Kappa- opioids activate these
-Analgesia, sedations, and decreased GI motility
Classifications of Opioids
- Pure opioid
- Agonist-antagonist opioid
- Pure opioid antagonist
Morphine
Strong Opioid Analgesic
Schedule II- moderate to high abuse potential
Therapeutic Use:
- Analgesia
- More effective against dull pain, than sharp intermittent
- Post operative pain, cancer pain, labor and delivery pain
- Can be used for MI, dyspnea with heart failure
MOA:
binds to mu receptors
Adverse Effects:
- Respiratory depression
- Constipation
- Orthostatic hypotension
- Urinary retention
- Cough suppression
- Biliary colic- gallbladder attack- right upper quad. Pain. Blocked bile duct of the galbladder
- Emesis
- Elevated intracranial pressure- make sure their blood pressure is normal
- Euphoria/Dysphoria
- Sedation
- Miosis- more pupillary constriction
- Birth defects
- Neurotoxicity
Pharmacokinetics:
Routes of administration-
PO, IV, IM, SUB Q, Epidural, intrathecal- lower dose in the spine
-poor lipid solubility ( does not cross the blood brain barrier easily)
-inactivated by the liver and eliminated through the kidenys
TOlerance:
- With MSO4 tolerance develops to analgesia, euphoria, sedation, and respiratory depression. Tolerance typically only occurs with long term use or giving large loading doses or taking it more frequent then prescribed.
- Tolerance does not develop to constipation or miosis (pinpoint pupils)
- Cross tolerance exists among other opioid agonists- tolerance of different drugs in the same drug class
Physical Dependence:
- Abstinence syndrome when withdrawn
- Intensity of withdrawal parallels the degree of physical dependence
- DO NOT WITHDRAWAL ABRUPTLY
- Strong Opioid Analgesics
Precautions:
- Decreased respiratory reserve
- Labor and delivery
- Head injury- increase their ICP
- Old and young- hold on to drugs for longer. Watch doses.
- Liver impairment- will hold on to drug for longer.
Drug Interactions:
-other CNS depressants, anticholinergic drugs, hypotensive drugs, Mao inhibitors, opioids
Dosage guidelines:
- fixed schedule
- monitor vitals signs, especially respiratory rate
Other Strong opioids
Fentanyl
- Parenteral
- Transdermal (Patch)
- Transmucosal
- Lozenge on a stick AKA Fentanyl pop- looks like candy. Beware of children
- Intranasal
Methadone
Hydromorphone
Meperidine
Moderate to strong Opioids
- Produce less analgesia and respiratory depression
- Produce sedation and euphoria
- Lower abuse potential
Adverse Effects- works on the same receptors
-Similar to MSO4
Examples:
Codeine
- 10% of the codeine dose is converted to MSO4 in the liver
- Some people lack the gene to metabolize codeine so it is ineffective
- Administered oral and parenterally
- Either alone or in combination with non-opioid analgesics (ASA or acetaminophen)
- Combination are effective because they relieve pain by different mechanisms
- Schedule II
- Combination products are Schedule III
- Only administered orally
- Effective cough suppressant
- *Nursing mothers should be alert for signs of infant toxicity such as excessive sleepiness, breathing difficulties, poor feeding—seek medical attention
Oxycodone, Oxycontin
- Oxycontin was reformulated in 2010 due to abuse
- New formulation bears the imprint OP the old formulation bears the imprint OC
- New formulation are harder to crush and if exposed to water or alcohol it turns into a gummy blob—cannot inject
Hydrocodone
-Combined with acetaminophen or ibuprofen
Agonist-antagonist Opioids
Pentazocaine
- Agonist at kappa receptors
- Antagonist at mu receptors
- Limited respiratory depression
Adverse effects similar to MSO4
-Can precipitate withdrawal in persons physically dependent on pure opioids
Buprenorphine
- Schedule III
- Partial agonist at mu receptors
- Antagonist at kappa
- Analgesic effects similar to MSO4
- Causes respiratory depression
- Can precipitate withdrawal in persons physically dependent on pure opioids
- Used in patients with severe chronic pain
- Solution for injection, transdermal patches, sublingual tablets, sublingual film
- Patches and solution for pain
- Sublingual products are used for opioid addiction
Using Opioids
- Pain assessment
- Prior to administration and I hour after and DOCUMENT pain scale
- VS- BP, HR, RR, o2 sat
What do we ask in a pain assessment????
- 0-10 sale
- Dosing
- Individual variation
Dosing schedule:
-Fixed
Specific Pain Treated with Opioids
- Postoperative
- Obstetrical
- Myocardial Infarction
- Head Injury
- Cancer Related Pain
- Chronic Noncancer Pain
Physical Dependence/Abuse/Addiction
- Physical Dependence
- Abstinence syndrome occurs if the dependence producing drug is abruptly withdrawn
Abuse
-Drug use inconsistent with medical or social norms
Addiction
- A disease process characterized by continued use of a psychoactive substance despite physical, psychological, or social harm
- Patient fears about addiction
Patient Controlled Analgesia-
typically morphine or fentanyl
- Self delivery of medication
- There is a ceiling to the amount they can receive even if they keep pressing the button
- Drug and dosages
- Patient and family education
Opioid Antagoinist
Naloxone (Narcan)
- Blocks opioid actions
- Will reverse effects of opioids if patient is receiving opioids
- Analgesia, respiratory depression, sedation, euphoria
- Can precipitate withdrawal in an opioid dependent patient
- d/t lingering effects you may have to push it again even after you revived them the first time
- Routes
- IV, IM, subQ, Nasal
Methylnaltrexone (Relistor)
Used for opioid induced constipation
-Selective mu receptors
Route:
-subQ
Adverse Effects
- Diarrhea
- Abdominal pain
- Flatulance
- Nausea
Non-opioid Centrally acting analgeiscs
Tramadol
- Weak activity at mu receptors
- Spinal inhibition of pain
- Used for mild to moderate pain
Clonidine
- Alpha 2 agonist
- Blocks nerve pathways that transmit pain in the spinal cord
- Used for severe cancer pain not relieved by opioids
Sedative-Hypnotic Drugs
- Drugs that depress central nervous system (CNS) function
- Primarily used to treat anxiety and insomnia
- Antianxiety agents or anxiolytics
- Distinction between antianxiety effects and hypnotic effects is often a matter of dosage
Sedative-hypnotics
Benzodiazepines
- Diazepam (Valium)
- Lorazepam (Ativan)* can give in IV form
- Midazolam (Versed)* Can give in IV form
- Alprazolam (Xanax)
Overview of pharmacologic effects:
- Central nervous system
- Reduce anxiety and promote sleep
- Cardiovascular system
- Oral vs. intravenous
- Respiratory system
- Weak respiratory depressants- be careful when mixing with opioids
Pharmacokinetics
- Absorption and distribution
- Readily cross the blood brain barrier
Metabolism
- Metabolites are pharmacologically active
- Time course of action
- Differ from one another in onset and duration and tendency to accumulate
Therapeutic uses:
- Anxiety
- Insomnia
- Seizure disorders
- Muscle spasm
- Alcohol withdrawal
- Perioperative applications
Adverse effects:
- CNS depression
- Anterograde amnesia- unable to make new memories
- Sleep driving
- Paradoxical effects
- Respiratory depression
- Great Abuse potiential
- Use in pregnancy and lactation
Other adverse effects
-hypotension
Drug interactions:
- other CNS depressants
Tolerance and physical dependence
- Tolerance
- With prolonged use, tolerance develops to some effects but not others
- Physical dependence
- Can cause physical dependence, but the incidence of substantial dependence is low
- Acute toxicity
Oral overdose: Drowsiness, lethargy, and confusion
Intravenous toxicity: Life-threatening reactions, profound hypotension, respiratory arrest, and cardiac arrest
General treatment measures
Oral: Gastric lavage, activated charcoal, saline cathartic, and dialysis
-Acute toxicity
-Antidote (Romazicon)
-Competitive benzodiazepine receptor antagonist
-Reverses the sedative effects of benzodiazepines but may not reverse respiratory depression
-Approved for benzodiazepine overdose and for reversing the effects of benzodiazepines after general anesthesia
-Routes of administration
-Oral
-Parenteral (intramuscular and intravenous)
Management of insomnia
Treatment is highly dependent on the cause
Non-drug therapy 1st -avoiding naps -decrease caffeine -exercise (no later that 7p) -environmet therapy with hypnotic drugs
