While you may need your caffeine fix on most occasions, avoid coffee or any other drink with it before your next interview. Your adrenaline doesn't need that jolt, and it will likely harm it instead, says Desha Peacock, director of career development at Marlboro College.
Peacock offered that advice in a Huffington post article:
Avoid drinking caffeine before an interview to help prevent the 'sweaty palm syndrome'. Caffeine is anxiety inducing and can make you seem too chatty. Lay off the coffee before you head in for an interview.
The advice seems in line with what caffeine does to your brain. Save the coffee for afterwards.
9 Tips to Stay Calm During an Interview [The Huffington Post]