Hydrochlorothiazide / triamterene
"This medicine nearly killed me, and I'm a healthy 33 year old woman who was on it for 4 days.



I was prescribed 50mg of hydochlorothiazide  to take instead of 50 mg atenolol which had been giving me side effects.



By day 4, I was incredibly weak, mentally foggy/confused, and had severe body aches. Also started experiencing chest pains, so I went to the ER, and my EKG showed an abnormal arrhythmia. 



Turns out my potassium had dropped to below 2.5, which can be life threatening. I was given 2 IV bags of potassium, 2 more bags of fluids, and kept overnight. I was fine in the morning (normal EKG and electrolytes) but was told one more day on that med could have been fatal. 



Be careful on this drug."