1. Clinical Overview
Calcium Chloride (10% w/v) is a sterile, hypertonic, clear, colorless solution for intravenous administration. It is a critical electrolyte replenisher and a source of calcium ions, which are essential for cardiac function, neuromuscular transmission, blood coagulation, and cellular membrane integrity. In the Indian context, it is a vital drug in emergency medicine, critical care, and perioperative settings, used to manage hypocalcemia, hyperkalemia, hypermagnesemia, and calcium channel blocker toxicity.
| Onset | Duration | Bioavailability |
|---|---|---|
| Immediate upon intravenous administration. | Approximately 2-3 hours, depending on the clinical condition and metabolic demand. | 100% when administered intravenously. |
2. Mechanism of Action
Calcium chloride dissociates in plasma to provide free, ionized calcium (Ca2+). Ionized calcium is a fundamental intracellular messenger and a critical cofactor for numerous enzymatic processes. It increases myocardial contractility (positive inotropic effect), enhances vascular smooth muscle tone, and is essential for the release of neurotransmitters and hormones. In hyperkalemia, it stabilizes the cardiac membrane by increasing the threshold potential, counteracting the depolarizing effect of high extracellular potassium.
3. Indications & Uses
- Symptomatic Hypocalcemia (Tetany, Seizures, Laryngospasm)
- Life-threatening Hyperkalemia (with ECG changes like peaked T-waves, widened QRS)
- Hypermagnesemia (especially due to magnesium sulfate toxicity)
- Calcium Channel Blocker Overdose (as an antidote)
- Cardiopulmonary Resuscitation (in cases of electromechanical dissociation or hyperkalemia/hypocalcemia)
4. Dosage & Administration
Adult Dosage: Hypocalcemia: 5-10 mL (136-272 mg elemental calcium) IV slowly over 5-10 minutes. May repeat as needed based on serum calcium. Hyperkalemia/Hypermagnesemia/CCB Overdose: 5-10 mL IV over 2-5 minutes. Can repeat in 5-10 minutes if ECG changes persist.
Administration: MUST BE ADMINISTERED INTRAVENOUSLY ONLY. Use a large bore IV line, preferably a central venous catheter. For peripheral administration, use a large vein (e.g., antecubital) and ensure perfect needle placement. Infuse SLOWLY: over 5-10 minutes for hypocalcemia, over 2-5 minutes for emergencies. Monitor ECG and blood pressure continuously during infusion. DO NOT IM or SC. Incompatible with many drugs (e.g., ceftriaxone, phosphates, carbonates, sulfates) - flush line before and after.
5. Side Effects
Common side effects may include:
- Sensation of warmth/flushing
- Taste of chalk or calcium (metallic taste)
- Peripheral vasodilation and hypotension (if infused too rapidly)
- Local irritation at injection site
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Digoxin/Digitalis | Synergistic effect on cardiac excitability, leading to severe arrhythmias (including ventricular fibrillation). | Major |
| IV Ceftriaxone | Risk of fatal precipitation of ceftriaxone-calcium salts in lungs and kidneys, especially in neonates. Do not administer within 48 hours. | Major |
| Thiazide Diuretics | Decreased renal calcium excretion, leading to hypercalcemia. | Moderate |
| Calcium Channel Blockers (e.g., Verapamil) | Calcium chloride is used as an antidote for overdose. It may antagonize the therapeutic effects of these drugs. | Major |
| IV Phosphates/Sulfates/Bicarbonates | Physical incompatibility leading to precipitation. Do not mix in same line. | Major |
| Suxamethonium | May potentiate neuromuscular blockade. | Moderate |
| Magnesium Sulfate | Calcium chloride is antidote for magnesium toxicity. Concurrent use may antagonize magnesium's effects. | Major |
| Quinidine | Increased risk of arrhythmias. | Moderate |
7. Patient Counselling
- This is an injectable hospital medication only.
- Inform doctor if you have kidney disease, heart disease, kidney stones, or are on digoxin.
- Report any pain, redness, or swelling at the IV site IMMEDIATELY.
8. Toxicology & Storage
Overdose: Hypercalcemia: lethargy, confusion, coma, polyuria, polydipsia, nausea, vomiting, constipation, pancreatitis, renal calculi, metastatic calcification, shortened QT interval on ECG, bradycardia, cardiac arrest.
Storage: Store at room temperature (15-25°C). Protect from freezing. Keep in original carton to protect from light. Do not use if solution is discolored or contains particulate matter. Single-use vial. Discard any unused portion.