Hyzaar combines a new kind of blood pressure medicine (prescribed alone as Cozaar) with an old-fashioned diuretic, hydrochlorothiazide (HCTZ).

It is prescribed for high blood pressure, especially if neither drug alone has lowered blood pressure adequately.

Hyzaar may be less effective for African-American patients.

Side Effects and Interactions

People on Hyzaar have experienced dizziness, weakness, insomnia, muscle cramps or pains, nasal congestion and sinusitis.

Other side effects reported include faintness, low blood pressure, diarrhea, vomiting, indigestion, chest pain and impotence.

Unusual but serious reactions to hydrochlorothiazide include rashes which require medical attention, allergic reactions (anaphylaxis) that involve difficulty breathing and shock, changes in blood, increased blood sugar, and disturbances in the balance of electrolytes.

Periodic blood tests are necessary to check on levels of potassium, magnesium, and other electrolytes. Report any symptoms to the physician promptly.

Dizziness or faintness may be worsened by alcohol, barbiturates, narcotic pain medicine, or dehydration through excess sweating, diarrhea or vomiting. Be especially careful when sitting or standing up.

Hyzaar is not appropriate during the second or third trimesters of pregnancy. If a woman taking Hyzaar becomes pregnant, she should consult her doctor as soon as possible.

The dose of diabetes medicine may need to be adjusted.

Questran and Colestid may reduce absorption of HCTZ and should be taken at a different time of day.

Muscle relaxants and cortisone-like drugs also have the potential to interact.

Arthritis drugs, including OTC NSAIDs like Advil or Aleve, may interfere with the effectiveness of HCTZ.

Lithium is not considered compatible with this diuretic and may become more toxic.

Hydrochlorothiazide alone can make the skin more sensitive to the sun. Avoiding sun exposure or using sunscreen and protective clothing are sensible precautions for those taking Hyzaar.

Tagamet may increase the level of Hyzaar slightly, while phenobarbital reduces it.

Interactions with other drugs such as erythromycin, Nizoral, or Sporanox have not been documented but are theoretically possible because losartan is metabolized by CYP 450 enzymes in the liver.

Licorice can greatly increase potassium loss due to medicines such as hydrochlorothiazide.

Check with your doctor and pharmacist to make sure Hyzaar is safe in combination with any other drugs or herbs you take.

Special Precautions

Hyzaar is not recommended for people with liver disease. Serious kidney problems may also interfere with the safe use of Hyzaar.

Hydrochlorothiazide can aggravate lupus (SLE). Make sure your physician is aware of your health history.

Taking the Medicine

Hyzaar may be taken when convenient, with or without food.

It is taken once or twice a day, according to the prescription.

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  1. Marion
    I was taking Losartan since 2009 . I had terrible weakness in legs, confusion among other things. Complained to my doctor who refused to listen. My symptoms got progressively worse. I. had pressure on in my eyes, lost my balance on a few occasions and slow digestion and bloating. In 2016 I felt like I was having heart attack. That was last straw. Stop taking meds and decided to go natural herbs. Feeling great as I exercise but at nights have popping and swishing in left ear. Withdrawal symptoms?

    On Lorsartan since 2009 . Had terrible side effects. Muscle weakness, confusion, terrible eye pain, burning on urination, loss of balance, boating and slow digestion and constipation . On 1/13/16 I felt like I was a heart attack and stopped taking pills. Now have popping and swooshing in left ear at night. Withdrawal symptoms ?

  2. Jerry

    Used Losartan HZTZ for 13 days. Yesterday when I bent over to pick up a dog toy I experienced debilitating dizziness. Went to sleep hoping it would stop, it did not. This morning almost fell to the floor putting on cloths. I am a healthy guy who works out and takes no other meds. Beware.

  3. l.e.

    Second day on losartan and experienced shortness of breath, dizziness, cold symptoms and severe diarrhea. Not using again. Taking something else

  4. LT

    I took Losartan HCTZ for about 5 years. I have had increasing problems with muscle pain, urine flow problems, terrible sleep problems and starting a few months ago extreme muscle weakness and joint pain. I have also had red/purple splotches on my arms, likely from sun exposure.
    About a week ago I missed a dose and the next day I noticed some relief from the muscle pain in my back. I took my blood pressure and it was tolerable so I skipped the dose. By the following day the knots and muscle pain in my upper back and lower legs was gone. Urine flow and voiding was back to normal and my head felt like it was working again. Joint pain is a bit better and muscles are still weak but it has been only a week so far.
    I left a message with my doctor about what I was doing and gave the daily BP readings that I have thus far. My sleep patterns are not yet improved but the quality of sleep may be better. My energy level has improved dramatically and is somewhat back to normal.
    Another thing is my appetite, possibly related to fatigue. It seemed like I couldn’t control my eating, and I was almost binge eating in the evening, continuing to eat after my evening meal. After a few days with no Losartan, I am able to eat a very moderate amount without binging on snacks. I almost feel like my life has been given back to me.
    I will continue to monitor my BP and keep my doctor notified of the results along with symptomatic improvements.

  5. JC

    Took Hyzaar for 5 years and was then switched to the generic form, which I took for 3 years. Realized the small skin outbreaks I experienced were Became sensitive to the sun. About 4 months ago had a bad allergic reaction (skin outbreak) after sitting in the sun for about 2 hours at a restaurant..
    Have not taken the medicine for over a month. This morning I walked to my office in the hot sun for about 10 minutes. About 4 hours later I had an allergic reaction – chills and chest pain, then broke out in small red pimples over most of my body.
    Does the sun sensitivity ever stop, if you stop taking the medicine?

  6. M.G.

    I have the same complaint. Falling asleep easily, middle of the day.

  7. blg

    sleeping after eating, can’t stay awake after I eat at all……..have to take a nap I am 58 years! Makes me so tired.

  8. benny

    swelling, itching, weight, gain rash on face (red) hate this medicine, muscle cramps, pain between shoulders blades……..I had to many problems to keep taken it…I will try something else ……..Thanks

  9. daw

    Dr. Switched me from Cozaar to generic. First brand mane by Audio Bingo did not lower blood pressure but did not produce any negative reactions. Pharmacy did re-fill with losartan potassium made by Sandoz. I now have dizzy spells and very low pulse (37) and systolic pressure which ranges from 148 to 102. I am also having back pain and some difficulty going to sleep as i seem to ache all over.

  10. Jannine

    This drug has made my bp go higher, but the dr does not believe it. Anyone else have this problem?

  11. Jerry

    I have been taking Lottrel for BP, I started on Losartan three days ago my complexion has improved 60% my gruff voice has also improved but my pulse rate has increased and I felt very nauseated this morning since starting on the Losartan.????????

  12. Niki B.

    I have a question about the drug Hyzaar. I have been on this pill for more than 18 years. I take it for high blood pressure in addition to Coreg and metolozone. Just recently, I was given the generic form of it and I have been experiencing leg swelling and pains and aches in my legs and shoulder blades. I am a diabetic and I take medication for that and high cholesterol.
    I never experienced any side effects from the brand and since I have been on the generic, I am not feeling well at all. Do you think that the change between the brand and generic can be causing my symptoms?

  13. jb

    I have been taking Hyzaar for 2 years. Occasional dizziness is the only side affect I’ve ever noticed. However at times my heart rate seems to speed up if I’ve missed a dose and take it the next night.
    Before this I was taking Covera and when they stopped making that I took Verapimil the main ingredient of Covera. My dosages were increased and when it was not affecting my blood pressure I was prescribed Hyzaar.
    My wife and I have been trying to have children for years. Our first pregnancy(unsuccessful) was right after I started taking Hyzaar. but now in my early 40’s, my sperm count is devastatingly low.
    Could Hyzaar be causing this? I was taking potassium suppliments after my Dr. informed me that Hyzaar can deplete your potasium levels. I stopped taking it recently when I read on another site not to take potassium suppliments witht Hyzaar. I generally eat at least 1 banana a day and have for years anyway. Thanks for any information!

  14. Lynne C.

    I have been feeling an uncontrollable sleepiness that sends me to nap a good two hours during the day and especially right after I’ve eaten. I’m 71 years old and still work so the toughest part of my day is right after lunch. When I get home from work I literally think I’m brain dead. I do exercise but the moment I sit down I’m asleep. Could this be the cause of the Hyzaar (Hydrochlorothiazide-Losartan 12.5) tablets I’ve been taking for many years? I was also on Lipitor (20 yrs) but two years ago I discontinued this medicine and now take alternative vitamins.

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