Выбрать правильную форму глагола.

1. Alcohol has / is having a very negative influence on the action of medicines.
2. These drugs have arrested / are arresting bleeding.
3. The urinalysis confirmed / was confirming the presence of albumin.
4. Alcohol usually increases / is increasing the toxicity of barbiturates by more
than 50 %.
5. Who prescribes / is prescribing the way of drug administration to a patient at
the moment?