Most adverse effects are mild and tend to diminish with continued therapy.
The following less frequent adverse experiences have also been reported in patients receiving clonidine hydrochloride, but in many cases patients were receiving concomitant medication and a causal relationship has not been established. Rare cases of sinus bradycardia and atrioventricular block have been reported, both with and without the use of concomitant digitalis. Other behavioral changes, vivid dreams or nightmares, restlessness, anxiety, visual and auditory hallucinations and delirium have rarely been reported. Dryness of the nasal mucosa was rarely reported. Dryness of eyes, burning of the eyes and blurred vision were reported.