This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Patient on Verapamil should not be given beta blocker to prevent: 
Select and explain. 
A. Conduction block, B. Bronchospasm, C. Neurogenic shock, D. Anaphylaxis
A: Conduction block
Answer: A: Conduction block 
Explanation: Adverse effects of CCBs - Nausea, constipation and bradycardia are more common with Verapamil.

 Verapamil can accentuate conduction defect-should be avoided in 2nd & 3rd degree block, in sick sinus syndrome and along with beta-blocker.
 Most common side effects of DHPs are palpitation, flushing, hypotension, headache, ankle edema, drowsiness and nausea.
 Nifedipine can paradoxically increase the frequency of angina in some patients.
 Nifedipine can cause voiding difficulty in elderly (relaxant effect on the bladder) and glucose intolerance (decreases insulin release).