When travelling with us after a family wedding about 6 hours away my son had a severe medical issue. We were called to his hotel room at midnight and found him shaking badly. He also had a rapid, erratic pulse and was clammy/sweating and felt nauseous (but didn't vomit). He didn't want us to call a doctor because he had a panic attack about 10 years ago with some of the symptoms (but not the shaking) and recovered OK. Thinking it was a panic attack we gave him a Zanax tablet plus a beta blocker tablet that we had with us. This helped after about 5 hours and the next day he was weak but very tired. We are not sure what caused this attack. In the week prior to the wedding he had some late nights partying with friends (alcohol was consumed but no illegal drugs were involved) and the wedding environment was similar. He was therefore very run down after the wedding. He was also very anxious at the wedding finding the stress and formality of the wedding difficult to handle. He had consumed a lot of alcohol and had little sleep the night before the wedding but consumed no alcohol on the day he had the attack. He did take a Zyrtec antihistamine for hayfever about 8 hours prior to the attack. We need to get an idea of what happened in case it happens again.