💊 Lecture 3 & 6
Drug Toxicities & Electrolytes
Lithium, Lanoxin, Dilantin, Aminophylline, Bilirubin. K+, Ca, Mg, Na rules.
Drug Levels
⭐
Pattern: 1s & 10s = Lithium & Lanoxin | 2s & 20s = Aminophylline, Dilantin, Bilirubin
| Drug | Therapeutic | TOXIC | Use |
|---|---|---|---|
| Lithium | 0.6–1.2 | >2.0 | Bipolar (mania only) |
| Lanoxin/Digoxin | 1–2 | >2 | A-Fib, CHF |
| Aminophylline | 10–20 | >20 | Airway bronchodilator |
| Dilantin | 10–20 | >20 | Seizures |
| Bilirubin (NB) | 0.2–1.2 (adults) | >20 (NB) | Hospitalize NB at 14–15 |
🧠
Kernicterus = Bilirubin >20 enters brain → FATAL. Opisthotonos (hyperextension) → place baby on SIDE
📌
Jaundice: Born yellow = Pathological (bad!) | Yellow at 2–3 days = Physiological (normal)
Aminoglycosides
💪 "A Mean Old Mycin" = Aminoglycosides
For serious, resistant, life-threatening gram-negative infections
Gentamycin, Vancomycin, Clindamycin, Streptomycin, Tobramycin
NOT aminoglycosides: Azithro/Clarithro/Erythromycin — they have "THRO" → THROW off the list!
NOT aminoglycosides: Azithro/Clarithro/Erythromycin — they have "THRO" → THROW off the list!
👂
Ototoxicity → Monitor HEARING (#1), balance, tinnitus (CN8)
🫘
Nephrotoxicity → Monitor CREATININE (24-hour > serum creatinine)
⏰ TAP — Trough, Administer, Peak
Trough = 30 min BEFORE next dose
Peak IV = 15–30 min AFTER bag empty | Peak IM = 30–60 min
Peak IV = 15–30 min AFTER bag empty | Peak IM = 30–60 min
Electrolytes
🧂 3 Electrolyte Rules
1. Kalemias: SAME as prefix (EXCEPT HR and UO — go opposite)
2. Calcemias: OPPOSITE of prefix
3. Magnesemias: OPPOSITE of prefix
Sodium: HypER = DEhydration | HypO = Overload
2. Calcemias: OPPOSITE of prefix
3. Magnesemias: OPPOSITE of prefix
Sodium: HypER = DEhydration | HypO = Overload
| Electrolyte | Hypo- S/Sx | Hyper- S/Sx |
|---|---|---|
| Potassium | Floppy, bradypnea, constipated, TACHYCARDIA, POLYURIA | Irritable, diarrhea, spastic, BRADYCARDIA, OLIGURIA |
| Calcium | Agitation, seizures, spasm, Chvostek, Trousseau (things go UP) | Bradycardia, lethargy, constipation (things go DOWN) |
| Magnesium | Things go UP (seizures) | Things go DOWN (lethargic) |
⚠️
Earliest sign of ANY electrolyte imbalance: Paresthesia (numbness & tingling)
Universal sign: Muscle weakness (paresis)
Universal sign: Muscle weakness (paresis)
🚨
Never push K+ IV! Max 40 mEq/L. Lower K+ fast: D5W + Regular Insulin → then Kayexalate (K Exits Late)
📖 Notes for Dummies
🧠 Think of it this way…
Drug levels are like a car's fuel gauge — too little = won't work, too much = breaks the engine. Electrolytes are like the fluid balance in your body — tip them too far in either direction and the body malfunctions.
💊
Just 2 patterns for drug levels:
Low numbers (1s & 2s): Lithium & Lanoxin
High numbers (10s & 20s): Aminophylline, Dilantin, Bilirubin
Low numbers (1s & 2s): Lithium & Lanoxin
High numbers (10s & 20s): Aminophylline, Dilantin, Bilirubin
👶
Bilirubin in newborns — simple story:
When red blood cells break down, they make bilirubin (yellow waste). Newborns' livers can't clear it fast. Too much turns skin yellow (jaundice). If it reaches the brain (kernicterus) — it can be fatal!
When red blood cells break down, they make bilirubin (yellow waste). Newborns' livers can't clear it fast. Too much turns skin yellow (jaundice). If it reaches the brain (kernicterus) — it can be fatal!
🧂
Electrolytes — 3 rules:
1. Potassium follows its prefix — EXCEPT HR and urine output flip opposite
2. Calcium does the OPPOSITE of its prefix
3. Magnesium also does the OPPOSITE
1. Potassium follows its prefix — EXCEPT HR and urine output flip opposite
2. Calcium does the OPPOSITE of its prefix
3. Magnesium also does the OPPOSITE
🫀
Potassium is the most dangerous electrolyte!
Too much K+ can STOP the heart. Too little makes it beat irregularly. NEVER push K+ IV — it could instantly stop the heart!
Too much K+ can STOP the heart. Too little makes it beat irregularly. NEVER push K+ IV — it could instantly stop the heart!
📝 Memory shortcuts:
🍌 Low K+ (hypokalemia) = floppy, slow bowels, FAST heart, peeing a lot
High K+ (hyperkalemia) = stiff, fast bowels, SLOW heart — CAN STOP YOUR HEART
🥛 Low calcium = TWITCHY, spasms, seizures — things go HAYWIRE
💧 Low sodium = TOO MUCH water | High sodium = TOO DRY
🍌 Low K+ (hypokalemia) = floppy, slow bowels, FAST heart, peeing a lot
High K+ (hyperkalemia) = stiff, fast bowels, SLOW heart — CAN STOP YOUR HEART
🥛 Low calcium = TWITCHY, spasms, seizures — things go HAYWIRE
💧 Low sodium = TOO MUCH water | High sodium = TOO DRY