This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: AIIMS 2019, Subject name: Pharmacology
Most commonly used route of administration of heparin for post-operative thromboprophylaxis is? 
Select and explain. 
A. Subcutaneous, B. Intravenous, C. Inhalational, D. Intramuscular
A: Subcutaneous
Answer: A: Subcutaneous 
Explanation: UFH is injected s.c. every 8- 12 hours, staed before surgery and continued for 7-10 day, or till the patient stas moving about. This regimen has been found to prevent postoperative deep vein thrombosis (post operative thromboprophylaxis) without increasing surgical bleeding. It also does not prolong aPTT or clotting time. However, it should not he used in case of neurosurgery or when spinal anaesthesia is to be given.