science

5-HT3 Inhibitors

💊 5-HT3 Inhibitors (ex: ondansetron) ⁠

🤢🤮 Nausea and vomiting are two of the most common presenting complaints ⁠

5-HT3 inhibitors (such as ondansetron) are one of the top 200 drugs prescribed and are used for the prevention of:⁠
🌟 chemotherapy-induced nausea and vomiting⁠
🌟 radiation-induced nausea and vomiting⁠
🌟 postoperative nausea and vomiting⁠
🌟 off-label for nausea and vomiting associated with pregnancy

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Vancomycin ⁠

💊 Vancomycin belongs to a class of antibiotics called glycopeptides. Drugs in this class are composed of a cyclic peptide bound by two sugar molecules (glycogen), hence the name glycopeptides! ⁠

🌟 MOA: binds to D-alanyl-D-alanine on the outer surface of cell membranes preventing cross-linking. This interferes with cell wall synthesis and results in bacterial cell death. ⁠

🧠 Another way to think of it: cell walls are like LEGO pieces linking together. The more that are linked, the stronger the structure is. Vancomycin prevents this cross-linking leading to an unstable structure. ⁠

🌟 Vancomycin = think mainly gram-positive coverage including MRSA! (gram-negatives do NOT have a thick cell wall and lack the D-ala-D-ala sequence, making vancomycin useless against them)⁠

🌟 NOTE: Recently, the term “red man syndrome (RMS)” has been replaced and is now recognized as “vancomycin flushing syndrome” or “vancomycin infusion reaction”. 

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Anion Gap Acidosis -

Mind the Gap- HAGMA

Anion Gap Acidosis -
⭐️ High anion gap metabolic acidosis (HAGMA) occurs when the body produces too much acid, or when the kidneys are not removing enough acid from the body.⁠
💊 Several drugs and toxins have been implicated as direct or indirect causes of HAGMA. The three most common ones to consider are methanol, ethylene glycol and salicylates.⁠
🌬️ Symptoms are generally non-specific, with dyspnea being common secondary to stimulation of the central respiratory center. Screening for toxic ingestions, including over-ingestion of aspirin and acetaminophen, is important. ⁠
🌟 Additionally, screening for features suggestive of diabetes (e.g., polyuria, polydipsia, polyphagia) or renal failure (e.g., nocturia, pruritus, anorexia) is essential.⁠
🌟 Primary treatment of high anion gap metabolic acidosis requires correction of the underlying cause

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Antiretrovirals

Antiretrovirals

Antiretrovirals

⭐ This is a great way to remember the names of antiretrovirals ⭐ Antiretroviral medications are used to treat HIV by blocking different stages of the virus’s life cycle (e.g., blocking entry into the host’s CD4 lymphocyte, inhibiting viral DNA from replicating, etc.)⁠ ⁠😖 However, learning the names of antiretroviral medications is horribly difficult. There are lots of drugs, with a dizzying array of names, abbreviations, and combination tablets.⁠ Hopefully, this will help you not to completely BLANK on which drug belongs to which type of antiretroviral! 🤓

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IV Fluids Review

💦 ⁠ IV fluids – What the tonic? ✏️The human body is composed of 60% water 💦 ⁠ -Two-thirds of it is available INTRAcellularly (space INside cells)⁠ -One-third of it is stored EXTRAcellularly (EXTERNAL space in blood vessels and around cells)⁠ ⁠ ⭐ There are different types of fluids with varying chemical compositions of salt and electrolytes that are designed to bring fluid into cells or keep fluid within the bloodstream.⁠ ⁠ 🔑 Key Tips:⁠ -Water flows where sodium (or particles) goes!⁠ -Solutions want to have the same ratio or balance of solvents (water) to solute (particles such as salt)⁠ -Water will flow from an area of low particles to an area of high particles⁠ -Semi-permeable membranes allow water to pass through but not particles⁠ ⁠ ⭐ First, think of the starting point as the space within blood vessels (or intravascular space) since IV fluids are infused directly into the bloodstream 🩸⁠ ⁠ ⭐ ISOtonic fluids: “ISOlated in the vasculature”⁠ -Equal amounts of water and particles so there is no movement between the compartments⁠ -Water from IV fluids stay ISOlated in the vasculature – used in situations where there is fluid loss and replacement is needed (ex: hemorrhage, diarrhea, vomiting)⁠ -Examples include: 0.9% sodium chloride (normal saline), dextrose 5% in water (D5W), lactated ringer (LR)⁠ ⁠ ⭐ HypOtonic fluids: “Out of the vasculature”⁠ -Low amounts of particles compared to water⁠ -Water flows OUT of the vascular into the cells⁠ -Used in situations where we have intracellular dehydration (ex: DKA, HHS)⁠ -Examples include: 0.45% sodium chloride (1/2 normal saline), 2.5% dextrose in water ⁠ ⁠ ⭐ HypErtonic fluids: “Enter the vasculature”⁠ -High amounts of particles compared to water ⁠ -Water ENTERS the highly concentrated vasculature from cells⁠ -Used in situations where there are swollen cells (ex: cerebral edema) or hyponatremia⁠ -Examples include: 3% sodium chloride (hypertonic saline), dextrose 10% in water (D10W) ⁠

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Vasopressors and inotropes

Vasopressors and Inotropes⁠

Vasopressors and inotropes
Vasopressors and Inotropes⁠

Vasopressors and Inotropes⁠

Vasopressors and inotropes OH NO! 🙇🏻‍♀️ These medications are commonly used in the critical care setting in patients with shock (or those with extremely low blood pressure) leading to end-organ damage (acute kidney injury, increased LFTs, etc.). ⁠

👉🏻 Vasopressors are drugs that cause vasoconstriction, therefore increasing mean arterial pressure (MAP). Vaso refers to blood vessels and pressor means to put pressure on or constrict making up the word – VASO-pressor. 🩸⁠

Examples of vasopressors include:⁠

⭐ Norepinephrine⁠
⭐ Epinephrine⁠
⭐ Vasopressin⁠
⭐ Phenylephrine⁠

👉🏻 Inotropes are drugs that affect cardiac contractility (or the force of muscular contractions). They can also be used as chronotropes (drugs that increase heart rate). THINK: Ino = strength; Chrono = time. Some vasopressors may also have effects on contractility and are called inopressors. ⁠

Examples of positive inotropic agents include: ⁠

⭐ Milrinone⁠
⭐ Dobutamine⁠
⭐ Dopamine⁠
⭐ Isoproterenone⁠

🧠 With the many different types of vasopressors and inotropes, it is important to understand how they work to use them effectively. Choosing the wrong agent or using it inappropriately, can harm the patient. ⁠

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IV chemotherapy agents with high emetic risks⁠

🌟 Chemotherapy agents are notorious for causing many side effects such as nausea and vomiting and are classified according to their emetic risk. 🤢🤮⁠ ⁠ 🌟 High-risk agents cause emesis in more than 90% of patients and require pre-treatment with medications such as 5HT3 antagonists (ex: ondansetron), neurokinin-1 receptor antagonists (ex: aprepitant), and dexamethasone. ⁠ ⁠ 🧠 A fun way to learn which IV chemotherapy agents have high emetic risk – think of this story: ⁠ ⁠ ‘The car had motion sickness and threw up, making splat sounds”⁠ ⁠ 🤔 Can you imagine it in your head? This story will help you remember the medications DACARbazine, Mechlorethamine, Streptozotocin, and ciSPLATin. ⁠ ⁠ 🌟 Other IV chemotherapy agents that have high emetic risk at higher doses or in combination with other medications include:⁠ ⁠ -Carboplatin AUC>4⁠ -Carmustine >250 mg/m2⁠ -Cyclophosphamide >1500 mg/m3⁠ -Doxorubicin >60 mg/m2⁠ -Epirubicin >90 mg/m2⁠ -Ifosfamide >2 g/m2/dose⁠ -AC (any combo that contains an anthracycline + cyclophosphamide)

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Antipsychotics

💊 Antipsychotics, also known as neuroleptics, are a class of medications primarily used to manage psychosis in schizophrenia or bipolar disorder, hence the name anti-PSYCHOTICS or anti-PSYCHOSIS (including delusions, hallucinations, paranoia, or disordered thought) 👹⁠ ⁠ They are broken down into two generations which differ by their side effect profiles: ⁠ ⁠ 1️⃣ 1st generation also called typical antipsychotics are associated with significant extrapyramidal side effects (movement disorder). ⁠ 2️⃣ 2nd generation also called atypical antipsychotics have decreased risks of EPS side effects as compared to 1st generation antipsychotics but are associated with significant weight gain and the development of metabolic syndrome.⁠ ⁠ In addition, all of the antipsychotics block the following receptors with varying degrees leading to the common side effects seen: ⁠ ⁠ ⭐ Dopamine: EPS symptoms⁠ ⭐ Alpha: hypotension⁠ ⭐ Muscarinic: anticholinergic side effects ⭐ Histamine: sedation⁠ ⁠ 🧠 MOA: In schizophrenia, dopamine is tied to hallucinations and delusions. Certain areas in the brain that ‘run off’ of dopamine may become overactive leading to symptoms of psychosis. Both generations block dopamine receptors, but second generations tend to act on serotonin receptors as well.

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Drugs that cause Constipation

🤓Let’s get down to the hard facts: some medications (notoriously opioids and anticholinergics) are associated with constipation. 💊They reduce activity in the nervous system and slow down the transit of food through the digestive system. The intestine walls absorb more fluid resulting in hard stools and constipation. 💧Drinking more fluids, eating more high fiber foods, and getting regular exercise may help relieve constipation. Using over the counter stool softeners and laxatives may also help.    

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Uterine Relaxant Drugs

👶🏻 Preterm labor occurs when labor begins too early. If this happens before the 37th week of gestation, the fetal organs, especially the lungs, might not be fully developed.⁠

💊 In these cases, labor can be suppressed with uterine relaxants that relax the uterine muscle and slow down contractions for up to 48 hours. It gives the fetus a few more days in the uterus as a corticosteroid is given to speed up the development of a preterm infant’s lungs. Steroids help the lungs mature and may promote the production of surfactant, a substance that prevents the collapse of alveoli (small sacs in the lungs where the air is exchanged). ⁠

💊 Uterine relaxants are also called tocolytics (toco = childbirth, lytic = terminate) and include several different types of drugs. ⁠

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Antibiotic Renal Dosing

Antibiotics are commonly used to treat infections. When considering what dose to prescribe to a patient, it is important to evaluate the patient’s renal function as many antibiotics are excreted by the kidney.⁠ ⁠ It is recommended to study the list of antibiotics that do NOT require renal dose adjustments rather than a list of the ones that do (as it can get very long and overwhelming). ⁠

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Diuretic Classes

There are 5 main types of diuretic classes with different mechanisms of action, site of action, and side effect profiles. ⁠ ⁠ 1) Loop diuretics work on the loop of Henle (as the name implies)⁠ 2) Osmotic diuretic work on the glomerulus⁠ 3) Thiazides work on distal convoluted tubule⁠ 4) Carbonic anhydrase work on the proximal tubule⁠ 5) Potassium-sparing diuretics (aldosterone antagonists and sodium channel blockers) work on the distal convoluted tubule⁠ and collecting ducts

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ketamine mnemonic

Ketamine Properties

ketamine mnemonic
📖 Ketamine is a medication primarily used for starting and maintaining anesthesia. It induces dissociative anesthesia, a trance-like state providing pain relief, sedation, and amnesia.⁠ ⁠ ⭐ The distinguishing features of ketamine anesthesia are preserved breathing and airway reflexes, stimulated heart function with increased blood pressure, and moderate bronchodilator.⁠

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Antibiotics that Cover MRSA

Methicillin-resistant Staphylococcus aureus (MRSA) is an infection caused by Staphylococcus (staph) bacteria that has an oxacillin minimum inhibitory concentration (MIC) of greater than or equal to 4 micrograms/mL. ⁠ ⁠ ⭐ MRSA infection is one of the leading causes of hospital-acquired infections and is commonly associated with significant morbidity, mortality, length of stay, and cost burden. ⁠ ⁠ ⭐ MRSA infections can be further divided into hospital-associated (HA-MRSA) infections and community-associated (CA-MRSA) infections. They differ not only in respect to their clinical features and molecular biology but also to their antibiotic susceptibility and treatment⁠

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Antibiotics that cover anaerobes

Anaerobic bacteria are bacteria that do not live or grow when oxygen is present. In humans, these bacteria are most commonly found in the gastrointestinal tract. ⁠ ⁠ 🔺 They play a role in conditions such as appendicitis, diverticulitis, and perforation of the bowel so it is important to make sure we have adequate anaerobic coverage when empirically treating these infections. ⁠ ⁠ 💊 There are several antibiotics that cover anaerobes in addition to other bacteria. ⁠

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