Hi Umpfan- If the blackouts/seizure episodes coincided with your being on Atenelol and at no other time, then the Atenelol might be the problem.
Perhaps by lowering your BP and heart rate TOO much (one of the primary side effects,) the drug, combined with heat and a hard workout did you in.
Side effects and adverse reactions are numerous with this drug:
Bradycardia (abnormally slow heart rate) THIS ALONE MIGHT HAVE CAUSED YOUR BLACKOUTS.
Cold Extremities
Postural Hypotension
Leg Pain
Dizziness
Vertigo
Light-headedness
Tiredness
Fatigue
Lethargy
Drowsiness
Depression
Visual disturbances (!)
Dreaming
Diarrhea
Nausea
Wheeziness
Dyspnea (shortness of breath)
Acute Myocardial Infarction
Heart Failure
Heart Block
Supraventricular Tachycardia
Atrial Fibrillation
Atrial Flutter
Ventricular Tachycardia
Allergic: Fever, combined with aching and sore throat, laryngospasm, and respiratory distress.
Want more?
Talk to your doctor, there are equally effective drugs available and especially the ARBs (angiotensin 2 receptor blockers,) like Benicar, Diovan which a lot of people eventually "discover" after they've suffered through all the side effects of the older drugs like atenelol..
Good luck,
zuzu xxxxx