Capstone Pharmacology

Pharmacology can be a tough area to review. There is so much info that it can be difficult to feel confident. While it is not possible to memorize it all, having a strong knowledge base of the classifications goes a long way. The ATI pharm review book is organized by classifications. Medications in the same classification often act in similar ways. So if you don't know much about a medication, but you know what classification the medication belongs to, you will better grasp the action and purpose for the client's needs. Here are some helpful tips to help you remember some of your classifications: Antiemetics An antiemetic is a medication used in the treatment and/or prevention of nausea and vomiting. Remember generic names are our friend because meds in the same classification often have similar generic names but brand names can come and go. Here are some common classes of antiemetics and their generic names – notice the similarities in the generic names: 5-HT3 receptor antagonists (serotonin antagonists) Dolasetron (Anzemet) Granisetron (Kytril, Sancuso) Ondansetron (Zofran) Tropisetron (Navoban) It’s ‘Tron’ to the rescue! Dopamine antagonists Promethazine (Phenergan) Prochlorperazine (Compazine) Metoclopramide (Reglan): Now this one is different in generic name because it can have some different side effects – watch for extra-pyramidal side effects with metoclopramide. Sometimes the generic names are not as helpful and you have to remember what meds fall under certain classes. Antihistamines and cannabinoids are used as antiemetics as well: Antihistamines (H1 histamine receptor antagonists) Diphenhydramine (Benadryl) Dimenhydrinate (Gravol, Dramamine) Meclizine (Bonine, Antivert) Cannabinoids Cannabis - Medical marijuana, in the U.S., it is a Schedule I drug. Dronabinol (Marinol) - a Schedule III drug in the U.S. *Remember most antiemetics can cause sedation so watch out for additive effect if given with narcotic analgesics and protect your client from injury. Proton Pump Inhibitors (PPIs) PPIs decrease stomach acid by inhibiting those gastric proton pumps that make the acid – they stop the acid at the pump! Remember generic names are our friends because meds in the same class often have similar generic names but brand names come and go: Here are some common PPIsOmeprazole (brand names: Prilosec, Zegerid, Omepral, Omez) Lansoprazole (brand names: Prevacid, Zoton, Inhibitol) Dexlansoprazole (brand name: Kapidex, Dexilant) Esomeprazole (brand names: Nexium, Esotrex) Pantoprazole (brand names: Protonix, Somac, Pantozol, Zentro) Think of a pump in your stomach just churning out the acid – ‘Zole’ is the nice guy who shuts off the pump. ‘Zole’ is very friendly (well-tolerated by most clients), but can cause vitamin B12 deficiency if he stays around too long (with long-term use). Erectile Dysfunction Agents Erectile dysfunction (ED) meds act by increasing nitric oxide which opens and relaxes the blood vessels of the penis causing increased blood flow (helping lead to getting and keeping an erection). Here is where the generic name is our friend again – meds in the same class often have similar generic names but brand names will come and go: Here are some common ED medsSildenafil (Viagra) Vardenafil (Levitra) Tadalafil (Cialis) Notice these end in ‘fil’. ‘Fil’ helps the nitric oxide to ‘fil’ the penis. While ‘Fil’ is a great guy (well-tolerated by most clients), he does have a few side effects – headache, flushing, back pain and muscle aches (with Levitra), temporary vision changes, including "blue vision" (with Viagra), and not all men can spend time with ‘Fil’. Men who have heart problems, uncontrolled blood pressure problems, history of stroke, or a health problem that can cause priapism can’t hang out with ‘Fil.’ Antianemics There are many causes of anemia and the antianemic prescribed will be based upon the cause. With iron deficiency anemia, iron supplements are commonly prescribed. Beware though - Iron is ‘heavy’ stuff and shouldn’t be taken ‘lightly’! · Iron can cause teeth staining (liquid form). Teach clients to dilute liquid iron with water or juice, drink with a straw, and rinse mouth after swallowing. · Iron can cause staining of skin and other tissues with IM injections. If IM route must be used, give IM doses deep IM using Z track technique. · Iron also has several drug administration interactions- of antacids or tetracycline’s reduces absorption of iron. Separate use by at least 2 hr. · Vitamin C increases absorption, but also increases incidence of GI complications. Avoid vitamin C intake when taking medication. · Instruct clients to take iron on an empty stomach such as 1 hr before meals to maximize absorption. Stomach acid increases absorption. However, iron can cause GI distress (nausea, constipation, heartburn). If intolerable, iron can be administered with food to increase compliance with therapy but this does reduce absorption. · Instruct clients to space doses at approximately equal intervals throughout day to most efficiently increase red blood cell production. · Inform clients to anticipate a harmless dark green or black color of stool. · Instruct clients to increase water and fiber intake (unless contraindicated), and to maintain an exercise program to counter the constipation effects. · Encourage concurrent intake of appropriate quantities of foods high in iron (liver, egg yolks, muscle meats, yeast). Statins HMG-CoA Reductase Inhibitors also known as ‘statins’ are some of the most prescribed medications in this country. Statins are used to treat primary hypercholesterolemia, for prevention of coronary events (primary and secondary), for protection against MI and stroke for clients with diabetes, and to help increase HDL levels in clients with primary hypercholesterolemia. Remember, LDL is the ‘bad’ cholesterol, and HDL is the ‘good’ cholesterol (HDL helps keep the ’bad’ cholesterol from building up in artery walls). You want your LOW (LDL) LOW and your HIGH (HDL) HIGH. Statins are another example that generic names are our friends – check out these common ‘statins’Atorvastatin (Lipitor) Simvastatin (Zocor) Lovastatin (Mevacor) Pravastatin (Pravachol) Rosuvastatin (Crestor) Fluvastatin (Lescol) While statins are a wonderful addition to our pharmaceutical arsenal, they are not without risk. When you think ‘statins’ think that we need to protect the liver and muscles stat: There is a risk of hepatotoxicity. It is important to obtain a baseline liver function and to monitor liver function tests after12 weeks and then every 6 months and to avoid alcohol. There is also a risk of myopathy and peripheral neuropathy. Clients should be told to report muscle weakness and/or aches, pain, tingling, and tenderness. CK levels will be monitored periodically during treatment as well. Anticoagulants Anticoagulants prevent the formation of blood clots by interfering with the clotting cascade, thereby preventing coagulation. The use of this class of medications is contraindicated with active bleeding, such as with bleeding disorders, ulcers, or hemorrhagic brain injuries. HEPARIN and COUMADIN are the two main anticoagulant medications. See the acrostics below for helpful hints and important facts about these drugs. HEPARIN H eparin sodium prevents thrombin from converting fibrinogen to fibrin. It is administered IV or SQ. E noxaparin (Lovenox) is a low-molecular weight heparin. It has the same action as heparin, but has a longer half-life. It is administered via subcutaneous injection. P rotamine sulfate is the antidote for heparin. A dminister heparin when there is the likelihood of clot formation, such as with myocardial infarction or deep-vein thrombosis. R isk for bleeding is the major side effect that clients should be educated about. Clients should be educated to monitor for bleeding, including bleeding gums, bruises, hematuria, and petechiae. I nstruct clients to avoid corticosteroid use, salicylates, NSAIDs, green leafy vegetables, and foods high in Vitamin K. N ormal activated partial thromboplastin time (aPTT) is 20 to 36 seconds, but to maintain a therapeutic level of anticoagulation while on heparin, the aPTT should be 1.5 to 2 times the normal value (60 to 80 seconds). COUMADIN C oumadin (generic name Warfarin sodium) interferes with coagulation factors by antagonizing vitamin K. O ral administration is typically used. Clients may need continued heparin infusion via IV until therapeutic effect of Coumadin is experienced (may take 3-5 days). U se is contraindicated in clients with low platelet counts or uncontrolled bleeding. M ephyton (trade name vitamin K) is the antidote for Coumadin. A dvise clients to avoid foods that are high in vitamin K, and avoid the use of acetaminophen, glucocorticoids, and aspirin. Clients should wear a medical alert bracelet indicating warfarin use. D oses are typically taken once daily. I NR and PT are monitored for clients who are taking Coumadin. Depending on intent of therapy, PT should be 1.5 to 2 times control and INR should be 2-3. Target INR is 3 to 4.5 for clients with a mechanical heart valve. N o Coumadin for pregnant women! Oral anticoagulants fall into Pregnancy Risk Category X. Heparin may be safely used in pregnancy. Antiplatelets PRIORITY POINT: Recall that this class of medications increases a client’s risk for bleeding because of their prevention of platelet aggregation. Nursing interventions and client education focus on the client’s increased risk for bleeding. Names to Know: · Aspirin (Ecotrin) · Clopidogrel (Plavix) · Pentoxifylline (Trental) How they work: Antiplatelets prevent platelets from clumping together by inhibiting enzymes and factors that normally cause arterial clotting. What they are used for: These medications are used to prevent myocardial infarction and stroke. Low dose therapy (81 mg) is effective for prevention of strokes and MI. How are they given: These medications are most commonly taken orally. They may also be administered IV. Nursing Interventions: WATCH FOR BLEEDING. · These medications should be taken with food. · These medications should be used cautiously in clients with peptic ulcer disease and in clients with severe renal/hepatic disorders. What do clients who are taking these medications need to know? · Observe for signs of weakness, dizziness, and headache and report them if they occur. These may be signs of hemorrhagic stroke. · Bleeding time should be assessed carefully. Coffee ground emesis or bloody, tarry stools should be reported. Watch for bruising, petechiae, and bleeding gums. What interactions may occur? · Avoid concurrent use of medications that enhance bleeding, including NSAIDs, heparin,and warfarin. · Corticosteroids should be avoided as they may increase aspirin effects. · Concurrent use of aspirin may reduce hypertensive action of beta blockers. Thrombolytic Agents In order to truly appreciate this drug tip, you need to familiarize yourself with the Ghostbusters. If you haven’t heard the theme song, cue it up before reading further. We promise it will be worth it. PRIORITY POINT: If the Ghostbusters had a medication class of choice, this would be it! Thrombolytic Agents are CLOT BUSTERS. They work QUICKLY to restore circulation. As such, they increase a client’s risk for bleeding. Who you gonna call? Streptokinase (Streptase). Call right away! These medications must be administered within 4 to 6 hours of onset of symptoms. If there’s something strange in your neighborhood: Thrombolytic agents dissolve clots that have already been formed. These medications convert plasminogen to plasmin, which destroy fibrinogen and other clotting factors. What’s the goal? Restoration of circulation, as evidenced by relief of chest pain, and reduction of initial ST segment injury pattern as shown on ECG. What’s the risk? Increased bleeding. These medications should only be given while the client is closely monitored. Baseline platelet and blood counts (including aPTT, PT, and INR) should be carefully assessed. Venipunctures and SQ and IM injections should be limited. After the clot has left the building: Administer beta blockers to decrease myocardial oxygen consumption and reduce the incidence and severity of reperfusion arrhythmias. Herb/Botanical Therapy Herbal supplements are widely used and have much less precise dosages than more regulated medications. Clients may not mention herbal supplements as a part of their medication history, so it is important to ask clients specifically if they are taking any supplements in addition to prescription or over-the-counter medications. Here are a few common herbal therapies: Echinacea: · Used to treat the common cold. · With chronic use, echinacea can decrease positive effects of medications for TB, HIV, or cancer. Ginger root: · Used to decrease nausea of morning sickness, motion sickness, and nausea induced by surgery. · May also decrease the pain and stiffness of rheumatoid arthritis. · These medications suppress platelet aggregation. · Should be used cautiously in pregnancy. Ginkgo biloba: · Promotes vasodilation and may be used to increase recall ability and mental processes. · Used commonly with dementia and Alzheimer’s Disease. · May also be used for erectile dysfunction in clients who take SSRIs and experience impotence as a side effect. · May interact with medications that lower the seizure threshold, such as antihistamines, antidepressants, and antipsychotics. · May interfere with coagulation. Valerian: · Increases GABA to prevent insomnia. · Promotes sleep with increased effect over time. There is a risk of dependence. · May cause drowsiness and depression. · Should be used cautiously in clients with mental health disorders. · Avoid use in pregnancy or while breastfeeding. Black cohosh: · Acts on the female reproductive system as an estrogen substitute. · May be used instead of estrogen therapy during menopause. · Increases the effects of antihypertensive medications and may increase effect of estrogen medications. · Increases hypoglycemia in clients who are taking insulin or other medications for diabetes. THE BOTTOM LINE: Clients who are taking herbal supplements should be advised to speak to their provider about possible interactions or adverse reactions that may occur. Insulins Insulins are used to manage diabetes mellitus, a chronic illness that results from an absolute or relative deficiency of insulin. There are various insulins that are available to manage diabetes. For each type of insulin, you will need to know the onset, peak, and duration. NCLEX questions may focus on when clients need to be assessed after insulin administration. Assessment should occur frequently, but especially during the PEAK of insulin action, as this is when hypoglycemia is most likely to occur. Signs and symptoms of abrupt-onset hypoglycemia include tachycardia, palpations, diaphoresis, and shakiness. Gradual onset hypoglycemia may manifest with headache, tremors, or weakness. We’ll CLIMB TO THE PEAK…starting FAST and ending SLOW. FASTEST: Rapid acting insulins:Lispro (Humalog). ONSET: Less than 15 minutes. PEAK: 30 minutes to 1 hour. DURATION: 3 to 4 hours. FAST: Short acting insulins: Regular (Humulin R). ONSET: 30 minutes to 1 hour. PEAK: 2 to 3 hours. DURATION: 5 to 7 hours. SLOW: Intermediate-acting insulins: NPH insulin (Humulin N). ONSET: 1 to 2 hours. PEAK: 4 to 12 hours. DURATION: 18 to 24 hours. SLOWEST: Long-acting insulins: Insulin glargine (Lantus). ONSET: 1 hour PEAK: None DURATION: 10 to 24 hours. Many students look for ways to more easily remember all of the ranges associated with insulin. It is helpful to think generally rather than trying to recall all exact numbers when memorizing this information, and, if you can only remember one thing about each insulin, CLIMB TO THE PEAK. Pick one number from each time frame (onset, peak, duration) to help reduce the values that you’re trying to memorize. Remember that onset, peak, and duration build sequentially as you move from one type of insulin to another, so it may be helpful to remember, for example, that onset times go from 15 minutes, to 30 minutes, to 1 hour (trend: all onsets are less than an hour). Peak times go from 30 minutes, to 2 hours, to 4 hours (trend: even numbers). Finally, duration goes from 3 hours, to 5 hours, to 24 hours. If you always organize your thoughts by O.P.D.(onset, peak, and duration), starting FAST (rapid acting) and ending SLOW (long acting) when studying the different types of insulin, these tips will be helpful. The key is consistency…looking at values in the same order every time. Test taking tips: Dealing with the dreaded ‘Select All That Apply’ question: These are tough. Try to make them true false questions so that you don't miss any correct choices. Read the question, read the first choice - ask yourself is it true or false (is it correct or not). If so check it. Read the question again and the next choice - ask yourself is it true or false. Is that true for all of the choices? Don’t allow the info from one answer choice influence you. Only the info in the stem of the question should be considered when picking your answers. Prioritization Tip: To avoid some common pitfalls when answering priority questions, be aware of the following: Never perform ABC checks blindly without considering whether airway, breathing, or circulation issues are acute versus chronic or stable versus unstable. For example, a client who is quadriplegic and on a ventilator has chronic airway/breathing problems. However, if there is not an acute consideration such as pneumonia, the client should be considered chronic and stable. This client would not be the nurse’s first priority. “Don’t count the days, make the days count.” -Muhammad