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Vancomycin ⁠

Leave a Comment / Infectious Diseases / Marlene Hernandez

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! ⁠
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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. ⁠
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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. ⁠
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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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Mind the Gap- HAGMA

Leave a Comment / Miscellaneous / Marlene Hernandez

⭐️ 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.⁠

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💊 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.⁠

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🌬️ 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. ⁠

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🌟 Additionally, screening for features suggestive of diabetes (e.g., polyuria, polydipsia, polyphagia) or renal failure (e.g., nocturia, pruritus, anorexia) is essential.⁠

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🌟 Primary treatment of high anion gap metabolic acidosis requires correction of the underlying cause

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Antiretrovirals

Leave a Comment / Infectious Diseases / Marlene Hernandez

⭐ 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

Leave a Comment / Miscellaneous / Marlene Hernandez

💦 ⁠ 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

Leave a Comment / Critical Care / Marlene Hernandez

Vasopressors and Inotropes⁠

Vasopressors and Inotropes⁠
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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.). ⁠
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👉🏻 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. 🩸⁠
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Examples of vasopressors include:⁠
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⭐ Norepinephrine⁠
⭐ Epinephrine⁠
⭐ Vasopressin⁠
⭐ Phenylephrine⁠
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👉🏻 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. ⁠
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Examples of positive inotropic agents include: ⁠
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⭐ Milrinone⁠
⭐ Dobutamine⁠
⭐ Dopamine⁠
⭐ Isoproterenone⁠
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🧠 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

Leave a Comment / Oncology / Marlene Hernandez

🌟 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

Leave a Comment / Psychiatry / Marlene Hernandez

💊 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

Leave a Comment / Gastroenterology / Memory Pharm

🤓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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Top Antibiotic Coverage Mnemonics

Leave a Comment / Other Learning Resources, Update / Memory Pharm

It is common for learners to struggle with memorizing antibiotic coverage when they are first introduced to the subject. With so many unfamiliar bacteria and antibiotics to know, it can be more than enough to get your head spinning.

In school, you probably learned the spectrum of activity for antibiotics by grouping bacteria into 3 common classifications:

Gram-positive bacteria (e.g., Streptococcus, Staphylococcus, Enterococcus)
Gram-negative bacteria (e.g., E. coli, Klebsiella, Salmonella, Shigella, Pseudomonas)
Atypicals (e.g., Chlamydophilia, Legionella, Mycoplasma)

Additionally, you learned that they are then further subclassified into aerobes, anaerobes, lactose-fermenting, and non-lactose-fermenting. But wait, don’t get cross-eyed just yet! Memorizing the spectrum of activity of antibiotics does not have to be that difficult. In this article, I’ll share some memorization tips on remembering the common bugs and what drugs cover them.

BUGS AND DRUGS

A great tip for remembering antibiotic coverage starts with memorizing the antibiotics that cover the major categories of bacteria including anaerobes and atypicals as well as resistant pathogens such as methicillin-resistant staphylococcus aureus (MRSA) and pseudomonas. From there, you can build upon your knowledge of other less commonly seen bacteria or infections through the application of the material during class, rotations, and clinical practice.

Needless to say, these are a MUST for you to know for exams. Review the mnemonics below and quiz yourself to see how much you remember.

NOTE: Clindamycin, doxycycline, and Bactrim (generic: sulfamethoxazole/trimethoprim) cover community-acquired MRSA infections while vancomycin, ceftaroline, and daptomycin cover hospital-acquired MRSA infections. Other antibiotics not listed include: linezolid, telavancin, dalbavancin, oritavancin, tigecycline (this mnemonic story can get pretty long!)

NOTE: Atypical bacteria do not color with Gram staining (because they lack a cell wall) and remain colorless. They are neither gram-positive nor gram-negative; they are ATYPICAL! 🙂

NOTE: These are the main antibiotics that empirically cover anaerobes. There are other antibiotics that do have some anaerobic coverage but since anaerobes are hard to culture and identify, empiric therapy is often used in practice.

NOTE: Other antibiotics not listed include: cefiderocol, colistin, ceftolozane/tazobactam

TIPS FOR SUCCESS

Keep in mind, memorizing these antibiotic spectra of activity can come in handy for exams but it doesn’t always apply to clinical practice (ex: you wouldn’t recommend daptomycin for MRSA pneumonia since daptomycin gets deactivated by the lung surfactants. You also wouldn’t recommend doxycycline as the first-line option for hospital-associated pneumonia.)
Other things to keep in mind when recommending an antibiotic to the team: potential toxicities, renal and hepatic function, CPK monitoring (esp. with daptomycin), which type of infection the drugs can or cannot be used for (moxifloxacin should not be used for UTIs as it doesn’t concentrate well in the urine making it ineffective), contraindications, drug interactions, and routine antibiotic doses (pneumonia dosing vs. bacteremia dosing)
At the end of the day, the best way to become comfortable with bugs and drugs is to practice, practice, practice. It takes time and effort but eventually, you’ll start to see a pattern with which antibiotic should be used based on patient-specific factors, cultures and sensitivity, and the type of infectious disease.

QUIZ YOURSELF

A) Which of the following antibiotics can be used for a patient with MRSA+ pneumonia?

Daptomycin
Vancomycin
Gentamicin
Azithromycin

B) All of the following antibiotics cover pseudomonas EXCEPT for?

Meropenem
Cefepime
Ertapenem
Piperacillin/tazobactam

C) A patient is in need of anaerobic coverage for a diabetic foot infection, which of the following antibiotics would provide adequate anaerobe coverage?

Levofloxacin
Cefepime
Clindamycin
Tobramycin

D) Which antibiotic would provide coverage for atypical pathogens and streptococcus pneumoniae in a healthy patient diagnosed with community-acquired pneumonia (assuming local resistance is low)?

Metronidazole
Clindamycin
Azithromycin
Amoxicillin

ANSWERS: A. 2, B. 3., C. 3., D. 3.

Hope these were helpful! If you have any additional memorization tips of your own, feel free to share them in the comments below.

If you are interested in learning more, check out our Antibiotics Pharmacology Coloring Book or Top 200 Drugs Made Easy Coloring Book for additional memorization tips!

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Uterine Relaxant Drugs

Leave a Comment / Gynecology / Memory Pharm

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

Leave a Comment / Infectious Diseases, Nephrology / Memory Pharm

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

Leave a Comment / Cardiology / Memory Pharm

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 Properties

Leave a Comment / Miscellaneous / Memory Pharm

📖 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

Leave a Comment / Infectious Diseases / Memory Pharm

⭐ 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