â¢Migraine headaches -- spots of light, halos, or zigzag patterns are common symptoms prior to the start of the headache. Other potential causes of vision problems include fatigue, overexposure to the outdoors (temporary and reversible blurring of vision), and many medications.
The usual initial dose of atenolol (Tenormin) for adult patients with hypertension is 50 mg taken once a day. The maintenance dose may be adjusted after a couple of weeks.
1 Heart Failure: Recommended starting dose is 12.5 mg or 25 mg doubled every two weeks to the highest dose tolerated or up to 200 mg. (2.3)  Hypertension: Usual initial dosage is 25 to 100 mg once daily. The dosage may be increased at weekly (or longer) intervals until optimum blood pressure reduction is achieved.