Makindo Medical Notes

⚠️ IV Calcium is life-saving in certain emergencies (e.g. severe hyperkalaemia, hypocalcaemia), but must be used with great care. 💡 Danger: IV calcium can provoke arrhythmias if given to patients on digoxin with low potassium. Always ECG monitor. 🔗 Always check the BNF before use: Calcium Chloride | Calcium Gluconate

📖 About

• Used in resuscitation/emergency medicine, often supplied as a Mini-Jet on the arrest trolley.
• Main role: Cardioprotection (e.g. stabilises myocardium in severe hyperkalaemia).

⚙️ Mode of Action

• Raises extracellular calcium → stabilises cardiac myocyte membranes.
• Buys time by reducing risk of arrhythmia until definitive correction (e.g. insulin/dextrose, dialysis).

💉 Formulations

• Calcium chloride: More potent but very irritant → best via central line (risk of tissue necrosis if extravasated).
• Calcium gluconate: Preferred if no central access (safer in peripheral veins).

📌 Indications

• Severe hyperkalaemia (K⁺ > 6.5 mmol/L with ECG changes).
• Severe hypocalcaemia (e.g. tetany, seizures).
• Calcium channel blocker overdose.
• Magnesium toxicity (e.g. excessive Mg infusion).

💊 Doses

• Hyperkalaemia: 10–20 mL calcium gluconate 10% IV. Repeat if ECG abnormalities persist. ✔️ Effect = narrowing of QRS / restoration of more normal ECG.
• Hypocalcaemia: 10 mL calcium gluconate 10% IV diluted in 100 mL 0.9% NaCl or 5% glucose, infused over 10–20 min. ➡️ In emergencies (e.g. tetany) may give neat, slowly, over ≥3 min with ECG monitoring.
• Infusions: Gluconate preferred for prolonged correction (less irritant).

🚫 Contraindications

• Absolute: Digoxin toxicity, Hypercalcaemia.

⚠️ Interactions

• ❌ Do not mix with bicarbonate or phosphate → precipitates.
• ⚡ Digoxin + IV calcium = risk of fatal arrhythmias (especially with hypokalaemia).

❗ Side Effects

• Local: Pain, phlebitis, severe tissue necrosis if extravasated.
• Systemic (rapid IV): Hot flush, hypotension, bradycardia, arrhythmias, cardiac arrest.
• Oral: GI upset (nausea, constipation, diarrhoea). Interferes with absorption of tetracyclines, iron, bisphosphonates → leave 3 hrs gap.

📚 References

• NHS Guidance on Hypocalcaemia