Can magnesium tablets be given through a Nasogastric (NG) tube?

Magnesium Tablets Through Nasogastric Tubes

Avoid giving magnesium tablets through a Ryles tube (nasogastric tube); instead, use liquid magnesium formulations such as elixirs or suspensions to prevent tube blockage and ensure proper drug delivery. 1

Why Tablets Should Be Avoided

Crushed tablets are particularly problematic for nasogastric tubes and should be avoided whenever possible. The Gut guidelines explicitly warn that crushed tablets, along with hyperosmolar drugs, potassium, iron supplements, and sucralfate, are particularly likely to cause tube blockage. 1 This is a critical safety concern because:

• Feeding tubes block easily, especially when medications are not in appropriate formulations 1
• Tube blockage can compromise both medication delivery and nutritional support 1
• Crushing medicines carries potential risks of drug exposure and inaccuracies in dosing 1

Recommended Approach for Magnesium Administration

Use liquid magnesium formulations exclusively when administering through nasogastric tubes:

• Preferred formulations: Magnesium elixirs or suspensions should be used rather than syrups 1
• Compatibility check: Only administer medications after establishing compatibility with the tube 1
• Pharmacist involvement: Adequate information should be provided to patients and carers with pharmacist involvement when using enteral tubes for drug administration 1

Specific Magnesium Options for NG Tube Administration

For patients requiring magnesium supplementation through an NG tube:

• Oral liquid magnesium preparations are available and appropriate for NG tube administration 2
• Magnesium oxide is the preferred oral supplement (when available in liquid form) as it contains more elemental magnesium than other salts 2
• Organic magnesium salts (aspartate, citrate, lactate) have higher bioavailability than magnesium oxide or hydroxide and may be available in liquid formulations 2, 3
• Typical dosing: 12-24 mmol daily for mild hypomagnesemia, with 12 mmol typically given at night 2

Essential Tube Flushing Protocol

Flush the tube before and after every medication administration to prevent blockage:

• Use fresh tap, cooled boiled, or sterile water 1, 4
• This flushing protocol is mandatory for all medications, not just magnesium 1, 4
• If blockage occurs despite proper flushing, it can often be cleared with warm water or an alkaline solution of pancreatic enzymes 1

When Oral/NG Route Fails

If oral magnesium therapy through the NG tube is inadequate or causes complications:

• IV magnesium sulfate can be used for severe deficiency 2
• Subcutaneous administration with saline is an option for patients requiring supplementation 1-3 times weekly 2, 5
• For cardiac arrhythmias associated with hypomagnesemia, IV magnesium 1-2 g bolus is recommended regardless of measured serum levels 2, 3

Critical Safety Considerations

Common pitfalls to avoid:

• Never shake low-dose ENFit tip syringes to remove drug moat, as this can alter dosing accuracy 1
• Most magnesium salts are poorly absorbed and may worsen diarrhea or stomal output in patients with gastrointestinal disorders 2, 3
• Use appropriate ENFit connectors (ISO 80369-3 standard) to avoid misconnection errors 1
• Magnesium should be used with caution in patients with kidney disease due to renal excretion 6