The most common adverse reaction in this and other studies were oedema, dizziness, bradycardia, hypotension, nausea, diarrhea and blurred vision. There may occasionally be dizziness, headaches and tiredness. These symptoms are usually mild and occur particularly at the beginning of the treatment. There may also be a considerably slowed pulse rate, gastrointestinal upset (nausea, abdominal pain, diarrhea, constipations and in isolated cases, vomiting) or flu-like symptoms. As a result of a possible increase in airway resistance, breathing problems can occur in patients with a tendency towards bronchial constriction (bronchospastic reactions).
Occasionally, particularly after taking the 1st dose of carvedilol, also when changing position from lying down to standing up, there can be an excessive drop in blood pressure (postural hypotension), with symptoms eg, dizziness, going black before the eyes or in rare cases, fainting (syncope). In rare occasions, there may be angina pectoris or conduction disturbances from the atrium to the ventricle of the heart. Rarely, there can be an exacerbation of symptoms in patients suffering from intermittent claudication or vascular spasms in fingers or toes (Raynauds' phenomenon).
Cold hands and feet have only been observed in isolated cases.
It is also possible for latent diabetes to become manifest, for already existing diabetes to become aggravated or for blood sugar counter-regulation to be inhibited. The signs of low blood sugar (eg, a rapid heart rate) may be masked.
There have been reports of isolated cases of allergic skin reactions (eg, rashes and itching), depressed moods, sleep disturbances, disturbances of vision, eye irritation, disturbances of sensation (paraesthesia), pain in the limbs, potency disturbances, intensification of existing heart failure, increases in certain liver values in the blood (serum transaminases) and reduced platelets and white blood corpuscles (thrombopenia, leucopenia). Users of contact lenses should be aware of the possibility of reduced lacrimation.