Bontril is best taken on an empty stomach one hour before meals. Sustained-release or long acting products must be swallowed whole. Crushing or chewing them will destroy the long action and may cause increased side effects. Because Bontril may cause sleeplessness, avoid taking a dose late in the day. Take Bontril as prescribed. Do not take Bontril more often or longer than directed. It is usually taken for 8 to 12 weeks. Use in combination with other appetite suppressant medicine is generally not recommended. Consult your doctor before such use.