Atenolol: Dyspnoea, wheeziness, bradycardia, hypotension, cold extremities, fatigue, dizziness, insomnia, lethargy, confusion, headache, depression, nightmares, nausea, diarrhoea, constipation, impotence, paraesthesia, rash, Raynaud's phenomenon.
Chlorthalidone: Orthostatic hypotension, GI disturbances, jaundice, pancreatitis, vertigo, lethargy, paraesthesia, photosensitivity, rash, muscle cramps, hypokalaemia, hyponatraemia, hyperglycaemia, hyperuricaemia or gout, leucopenia, agranulocytosis, aplastic anaemia, thrombocytopenia.
Potentially Fatal: Atenolol: Heart failure, 2nd or 3rd degree AV block. Chlorthalidone: Hypersensitivity reaction including toxic epidermal necrolysis.