A 3-year old female child sleeping in a thatched hut woke up in the middle of the night screaming. Her mother thought the child had a nightmare and tried to pacify her. After sometime she noticed that the child was sweating profusely and the hands becoming cold, child also vomited a couple of times. The mother immediately rushed the child to the emergency services. His pulse was 150/minute and his BP 90/60 mm Hg. The first line of treatment for this condition is-