What is a contraindication for administering Magnesium in emergency care?

• A. High blood pressure
• B. History of renal failure
• C. Asthma
• D. Normal kidney function

Answer: (B)

Renal clearance is the key factor determining whether magnesium can be given safely. Magnesium is eliminated primarily by the kidneys, so in renal failure its levels can accumulate and cause dangerous effects such as hypotension, bradycardia, respiratory depression, and loss of reflexes. That makes a history of renal failure a clear contraindication to magnesium administration in emergency care.

Other considerations: high blood pressure by itself is not a contraindication, as magnesium is used in certain hypertensive emergencies and related conditions. Asthma is not a contraindication either; magnesium sulfate can be used as a bronchodilator in acute severe asthma in some cases. Normal kidney function is compatible with magnesium use since clearance is adequate.