Lecture 6 Drug Toxicity

LECTURE 6 DRUG TOXICITY • 5 main ones to know! -> tests nurse safety! -> remember, they don’t test units 1. LITHIUM • for the mania in bi-polar • therapeutic level = 0.6 - 1.2 • toxic level = > 2 • What about between 1.2 - 2???! -> no books agree on what is going on in between ! those levels (grey area)! -> boards would not give you any values in the grey ! area (because item writers for the NCLEX need to ! test on what the books agree and books agree that ! over 2 is toxic) 2. DIGOXIN (LANOXIN) • used to basically treat 2 things:! a) A-fib ! -> remember the ABCD’s of treating atrial arrythmias! b) congestive heart failure • therapeutic level = 1 - 2 • toxic level = > 2! *** NOTE: both have 2! -> so if the question uses the ! value of 2, call it toxic (safer to call something ! toxic when it may not be than to say that it’s ! therapeutic when it might not be) • take the apical heart rate before giving Dig 3. AMINOPHYLLINE • airway antispasmodic! - technically not a bronchodilator -> it doesn’t ! stimulate beta-2 agonist cells to bronchodilate! - it just relaxes a muscle spasm! -> in spasms = airway is narrow! -> when you relax a spasm, airways widen (which ! is why it looks like a bronchodilator)! * ex. epinephrine is a bronchodilator • ex. sometimes PT’s come in w/ an acute asthamatic attack & the bronchodilators aren’t working -> because they are in an acute, lock-down spasm & the spasm is in the way of the bronchodilator! = give them aminophylline first to relieve the spasm! = then you can give the bronchodilator after and it ! will work • therapeutic level = 10 - 20 • toxic level = > 20 4. DILANTIN (PHENYTOIN) • anticonvulsant; treat seizures • therapeutic level = 10 - 20 • toxic level = > 20 5. BILIRUBIN • waste product from the breakdown of RBC’s • Hint: Boards will only test bili’s in newborns! - normal adult bili = 1-2 (low)! - newborns have higher levels from breaking down ! RBC’s from mom = 5 + • therapeutic level -> elevated level = 10 - 20! - ex. if newborn has 9.9 it’s high but still “normal” • bilirubin toxicity = > 20! - right around 14-15 is when MD’s start thinking about ! hospitalization because once you’re at 15, you’re ! halfway to toxic (don’t want it to get to 18 or 19, too ! close to toxic) • pathologic jaundice = bili high & infant yellow at birth! - come out yellow • physiologic jaundice = bili is normal at birth but over the next 2-3 days it goes high ! - becomes yellow • HINT:! - for the two “L” drugs = 2 (pick the lower number)! - the other one’s = 20 (pick the higher #) Kernicterus & Opisthotonos: • kernicterus = bilirubin in the brain when it crosses the BBB (condition) -> is in the brain, in the CSF, in the meninges! - different from jaundice = yellow color from too much ! bilirubin in the skin! - usually occurs when you reach levels of 20! - bili in the brain causes aseptic meningitis & aseptic ! encephalitis; can be lethal • opisthotonos = position the baby assumes when they have bilirubin in the brain! = severe hyperextension due to the irritation of the ! meninges w/ the bilirubin! -> newborns have high flexibility so when they ! hyperextend they’re heels will touch their ears & ! they will be rigid! -> if you see a kid w/ levels of 15 extending the ! neck they need follow-up immediately (medical ! emergency) • ex. In what position do you place an opisthotonic child? = on their side ABDOMINAL DUMPING SYNDROME vs. HIATAL HERNIA • both gastric emptying issues & are kind of opposites! -> memorize one & you have the other ! Hiatal Hernia: • regurgitation of acid into the esophagus because the upper part of your stomach herniates upward through the diaphragm! - your stomach should stay in the abdominal cavity • w/ this, you have a 2-chamber stomach (like having ! 2 stomachs) -> band around the middle • gastric contents move in the wrong direction at the correct rate! -> rate is not the problem, it’s the direction! -> going the wrong way on a one way street • S & S:! - just plain GERD (gastro-esophageal reflux disease)! -> heartburn & indigestion! *** but just because you have GERD doesn’t ! mean you have hiatal hernia! - hiatal hernia is GERD when you lie down after ! you eat (the GERD only occurs after lying down)! - you cannot have hiatal hernia if your symptoms ! occur before lying down because hiatal hernia is ! dependent on position & meal time • Treatment:! —> goal = want the stomach to empty faster! * because if it’s empty, it won’t reflux! ** see table! Dumping Syndrome: • gastric contents dump too quickly into the duodenum! - usually follows gastric surgery • gastric contents move in the right direction at the wrong rate! -> the rate is the problem -> speeding • S & S:! ** long list of issues so take what you know & ! combine them to equal dumping syndrome! - drunk person -> staggering, slurring, impaired ! judgment, delayed reactions, labile emotions! -> from decreased blood flow to the brain because ! all the blood is going to the gut (because it ! dumped into the duodenum)! - shock -> classic sigs such as hypotension, ! tachycardia, tachypnea, pale, cold & clammy! - acute abdominal distress -> cramping pain, ! doubling over, guarding, borborygmi, diarrhea, ! bloating, distention, tenderness! - so, think drunk + shock + acute abdominal distress • Treatment:! —> goal = want the stomach to empty slower! ** see table • Three things to play around w/ to effect stomach emptying time:! a) change the head of the bed! b) change the water content of the meal! c) change the carbohydrate content of the meal Gastric Emptying Issue Treatments Head of Bed HIATAL HERNIA Water Content - high fluids Carb Content - high carbs ! because they go ! through faster - low protein Protein? - HIGH position ! during & after ! meals (gravity ! helps empty faster) DUMPING SYNDROME - LOW position (lie ! flat and turn to ! side to eat) - low fluids (don’t ! give fluid w/ the ! meals -> an hour ! before or after) - low carbs to help ! stomach empty ! slow - high protein • Hint: Whatever carbs is, protein is the opposite. ELECTROLYTES • to know the S & S of electrolyte disorders, memorize 3 sentences:! a) Kalemia’s (K+ imbalances) do the same as the ! prefix except for heart rate & urine output. (write ! arrows to help)! b) Calcemias (Ca) do the opposite of the prefix.! c) Magnesemias do the opposite of the prefix. • Kalemia’s do the same as the prefix except for heart rate & urine output: ! - look at the prefix: hyperK+ & hypoK+ (high & low)! - symptoms will go HIGH w/ HYPER, LOW w/ HYPO! -> except for the heart rate & urine which goes ! opposite the prefix! S&S Brain HYPER K+ irritability, aggitation, restlessness, agressions, obnoxiousness, decreased inhibitions, loud/boistrous Lungs tachypnea LOW heart rate! Heart - T waves = peaked (tall)! - ST wave = elevated! *** everything else about the ! heart aside from the rate go up Bowel diarrhea, borborygmi Muscle spasticity, increased tone, hyperreflexive LOW urine output Urine HYPO K+ lethargy, obtunded, stupor bradypnea HIGH heart rate (tachycardia) illeus, constipation flaccidity, low reflexes HIGH urine output • ex. Your PT has hyperK+. Select all that apply:! a) dynamic illeus e) U wave (goes down) -> sign of cardiac depression! b) obtunded f) depressed ST wave! c) +1 reflex g) polyuria! d) clonus h) bradycardia • Hint: don’t forget, if you don’t know something don’t pick it (don’t over select) • Calcemias do the opposite of the prefix. ! - hyperCalcemia = body goes low! -> ex. bradycardia, bradypnea, flaccidity, lethargy, constipation! - hypoCalcemia = body goes high! -> ex. agitation, clonus, hyper-reflexive, seizure, tachycardia • Trousseau’s sign = put BP cuff on the arm and watch to see if the hand spasms when it’s pumped up • Chvostek’s sign = tap the cheek -> watch for face spasms (hypocalcemia)! - sign of neuromuscular irritability associated w/ low Ca! -> Hint: in hypoCa it does the opposite of the prefix ! so irritability would have to be hypoCa • Magnesemias do the opposite of the prefix. ! - some review books say that hypomagnesemia is not ! associated w/ hypertension BUT it is • Could it be possible that certain symptoms could be caused by either a K+, Mg, or Ca imbalance? YES (How do you break the tie?)! - in a tie, don’t pick Mg because it’s not a major player • If it is skeletal muscle or nerve, blame it on Ca! -> for everything else blame it on K+! - ex. Your PT has diarrhea. What caused it?! a) hyperK+ -> same as prefix so could be this! b) hypoK+ -> things go down so not this one! c) hypoCa -> opposites of prefix so could be this! d) hypoMg -> opposites of prefix so could be this! ** in a tie, don’t pick Mg; if it’s not skeletal or ! nerve you rule out calcium! ** Hint: when answering these kinds of questions, ! draw arrows! (i.e. diarrhea is an “up” symptom)! —> if the question had asked about tetany use the ! sentences (prefixes), arrows & tie breakers to ! help rule out options & because it’s muscle & ! nerve related, it’s hypoCa • Common mistake in electrolytes:! ex. Your PT has tetany. What caused it? (tetany is the ! body going up)! a) a high K+ -> makes body go up! b) a high Ca -> makes body go down! (opposites) ! c) a low Mg -> makes body go up (but it’s a tie)! —> 90% of students would pick Ca without properly ! looking at the question because the question is ! going the other way (use the sentences & arrows)! ** don’t do the tie breaker first • prefixes -> arrows -> tie breakers Sodiums: • d e hydration! - hypernatremia • o verload! - hyponatremia • dehydration & overload are opposites! -> think of the signs & symptoms of both situations • ex. In addition to a high K+, what other electrolyte imbalance is possible in DKA?! - hyperNatremia! -> because of dehydration • Earliest (first) sign of any electrolyte disorder:! = numbness & tingling -> paresthesia! ** circum-oral paresthesia (numb & tingling lips) is a ! very early sign • UNIVERSAL SIGN of electrolyte imbalance is muscle weakness = ALL of them cause this! = paresis Treating Electrolyte Imbalances: • the only one that really gets tested is K+! -> remember, high K+ is the most dangerous because ! it can stop your heart • Rules:! a) Never push K+ IV! b) Not more than 40 of K+ per L of IV fluid! -> call and clarify if there is an order for more ! (question the order if it’s over 40)! c) Give D5W w/ regular insulin (K enters early)! - fastest way to lower K+! -> this will drive the K+ into the cells out of the ! blood (it’s the K+ in the blood that kills you, not ! the ones in the cells)! -> this doesn’t get rid of the extra K+ but it hides it ! well (doesn’t really solve the problem BUT it ! saves their the PT’s life)! *** buys time to solve the underlying problem ! (but if you don’t fix it the K+ will eventually ! leak back into the blood) - temporary fix! d) Kayexalate (K exits late)! - full of sodium; sits in the gut! - route: oral ingestion or rectal enema! - trades sodiums for K+ so you can poop out K+! -> PT ends up w/ high sodium (hypernatremia)! *** which is then dehydration which is easier to ! treat (trading a life-threatening imbalance w/ ! a non life-threatening one BUT the PT will ! still have an electrolyte imbalance)! -> pro's of kayexalate = get’s rid of excess K+ ! permanently as it leaves the body! -> con’s of kayexalate = takes a long time (HOURS) ! & the PT may not live that long! • best way to get rid of K+ to fix the imbalance by using both D5W w/ reg. insulin + Kayexalate !