Why drugs administered by i.v rout

I.V. route of drug administration means intravenous injection of the drug. Here, the drug is directly injected into the vein.
The advantages are-
1. It can be employed in unconscious or uncooperative patients
2. It can be employed in cases of vomitting and diarrhoea.(in such cases,if drugs are administered via oral route, they will be excreted out in the vomitus or faeces)
3. Drugs which might irritate the stomach or are not absorbed by oral route can be administered
4. drugs which are destroyed by digestive juices (eg- insulin) or liver enzymes (eg-penicilin G) can be administered (first pass metabolism overcome)
5. Since drug is directly delivered into the circulation, bioavilability is 100%. therefore excellent accuracy of dose.
6.No time is wasted in absorption of drug, therefore rapid onset of action. therefore suitable for emergencies