Cozaar is the first of a new kind of blood pressure medicine, anangiotensin II blocker.

Cozaar is prescribed for high blood pressure, alone or in combination with other drugs. It appears to be less effective for African-American patients.

Side Effects and Interactions

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

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

Dizziness or faintness may be worse if a person becomes dehydrated through excess sweating, diarrhea or vomiting. Report any symptoms to the physician promptly.

Cozaar is not appropriate during the second or third trimesters of pregnancy. If a woman taking Cozaar becomes pregnant, she should consult her doctor as soon as possible. Nursing women should not take this drug without first discussing potential risks and benefits with their physician.

Tagamet may increase the level of Cozaar slightly, while phenobarbital reduces it. Interactions with other drugs such as erythromycin, Nizoral, or Sporanox have not been documented but are theoretically possible.

Cozaar is metabolized by CYP enzymes in the liver. As doctors gain more experience prescribing this medicine, more interactions may come to light. Check with your doctor and pharmacist to make sure Cozaar is safe in combination with any other drugs you take.

Special Precautions

People with liver disease may have trouble metabolizing Cozaar. The dose should be adjusted accordingly.

Taking the Medicine

Cozaar 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. Krista

    I recently had a bad flare up of raynauds. My doctor placed me on lossartan potassium 50mg once per day to try and open the capillaries in my feet. I have always had excellent blood pressure. After a few days on these Meds I experienced headache, dizziness, “foggy thinking,” fatigue and severe ringing in my ears. I have to get up very slowly or I get faint. I can’t do more then a walk on my treadmill where before I was running 30 min every day.

    Called my dr. He wanted me to stay on these meds. He said he doesn’t know why I’m experiencing these symptoms. After doing some research I figured these were side effects of the losartan. I saw a specialist yesterday. She immediately took me off the lossartan. Hoping to feel better soon. Does anyone know how long it takes for the side effects to go away? I’m tired of not being able to function very well.

    • Deb

      I’m not surprised your dr wants you to stay on losartan! Why are they so hard headed? I’ve been on losartan 100/25 since December 2014. and my body aches everywhere. I can’t do my exercise class because I ache so much. I know it’s the losartan causing this. I’m an active 61 year old grandmother and as of now I feel 91. It doesn’t do the greatest job at regulating my blood pressure either. I also have stomach cramps, diarhrea, dry mouth, anxiety to the point my dentist will not do a procedure because my blood pressure is elevated, I’m extremely fatigued. I have a dr appt, coming up and will be expecting another course of action be side this is horrible way to live

  2. Jean

    I was on Losartan Potassium for over five years. During this time I increasingly had leg, back and hip pain that I (and my doctor) attributed to getting older (I’m 52). I finally decided to stop taking it about two weeks ago. It took about four days for the pains to stop, I started feeling so much better, more energetic and less tired. Now three weeks later, I am pain free and NEVER taking that crap again. What a waste of my time and toll it took on my body. I must’ve taken Motrin every day thinking I needed it for old age pain.

  3. Eileen

    I have always tended to have somewhat low blood pressure but after being diagnosed with Breast cancer my BP increased significantly and my doctor put me on 50mg Losartan. In September I had developed a serious enough cough that it was diagnosed as bronchitis and I was put on 3 courses of prednisone and a couple of different antibiotics. When these did absolutely nothing I was sent to a pulmonologist who did a chest CT scan, pulmonary function test, sinus ct scan and a bronchoscopy with no results. I was diagnosed as having postnasal drip and put on Flonase, Zyrtec saline spray and a cough suppressant.

    By the 2nd week of January I had no improvement. I had developed severe headache probably from coughing so much and experienced gagging and most days vomiting of the excessive mucus my body was producing. I also back in November had started having stress incontinence from the violent coughing. All around pretty miserable.

    I was sent to an ENT doctor who examined by nose and throat and found nothing. He determined that I was experiencing a bad reaction to Losartan. I am tired all the time and now am back on steroids because my larynx is so swollen from coughing. I’ve been told it will take about a week before the symptoms will go away and remain hopeful that this nightmare will finally end.

  4. Cynthia
    Key West

    Never had a issue with HBP. In 2009 I had a severe cold and treated myself with over the counter cold meds. While at work I suffered a mini stroke (TIA) and was hospitalized with a blood pressure reading of 231/128. I was immediately put on Lopressor. A few years later I was changed to Losartan 50 mg. Since the very start I noticed severe muscle aches, crippling hand and feet spasms. Edema in both ankles and calves. I did not consider it was side effects from this drug until recently when I have taken a keen interest in the logistics of generic drugs. Today I am weaning myself off which I have been forewarned is a major No-No. I want quality in my life. I am 66 years old.

  5. kimberly p.

    been taking diovan for several months now, insurance wont pay for it anymore, so being switched to losartan, I am worried after reading all of these comments.

  6. Lee J.
    Lagrange Georgia

    I was put on Losartan potassium after two of my labs came back with very low potassium but after a month or so I have a tremendous about of muscle spasms/cramps. It’s been over a year now. I tell my doctor but he seems to not be concerned. He claims its my job is causing my muscle problems and very well could be but I have a potassium deficiency seems like that could be the reason my muscles cramp and hurt so much. It’s very interesting that so many people are on Losartan and having major muscle pain.

  7. steve

    Was put on 50mg to start with for secondary hypertension. Felt the side effect immediately (strange feeling in my head, not dizzy or light headed, but more like a fuzzy feeling) and asked for a new medication. I’ve been on lisinopril, amlodipine, labetalol, propranolol, spironolactone (was in combination with a BP med) and they never had side effects (was switched off for other causes).

    Losarton is by far the first medication I have ever taken and if this was my only option I’d rather not take anything.

  8. Stephany

    They gave me Losartan about 4 years ago, side effects were awful. I thought maybe it was just me so I tried it again. Insurance would no longer pay for Cozaar so the Pharmacist suggested I try Losartan again. This time I ended up in the ER with a massive headache, BP was high and the Doctor thought I was having a stroke, fortunately I was not having one, it was from the Pill. Then my Doctor put me on Benicar, I have had no side effects with that. But Insurance does not want to pay for it and again it wants me to take Losartan again and I refused. I guess at this point I am between a rock and a hard place. Any suggestions would be appreciated!

    • JT

      There are wonderful integrative physicians out there that treat alternatively first before they ever consider the pharmaceutical route. Please consider seeing one or a naturopath, DO, who can treat you holistically hopefully without meds. It is well-worth doing.

  9. Bettye C.
    Laguna Niguel CA

    I think I have posted before but in any case new developments. Losartan 100mg since March 2014 and Clonidine 0.1 mg at night. Hypertensive crisis out of the blue that landed me in ER x3 early part of the year. Spiking continued at night, thus the Clonidine which keeps it at bay. However, the blood work at the start of the year gave me an almost normal Cholesterol and Triglycerides. 9 mos later with all the drugs on board, the Cholesterol and Triglycerides increased enough to warrant a call from the Doctor. My diet is sterling and he agrees so. I found online the Framington study that revealed Losartan Potassium ( not the one with thiazides) increases cholesterol and triglycerides. I showed my Dr the paper and he was shocked. He is studying this. I would never grant an allowance to take statins and my Dr knows this and he did not push it. Cholesterol is paramount to develop stress hormones and neurotransmitter health and a million other critical things in our body. To lower it, brings on depression. Big pharma has profited from lowering cholesterol and guess what? it is only a symptom of poor exchange at the cell membrane and not the cause of atherosclerosis.

    My Dr. understands my body and has managed my meds to my satisfaction now and always points a finger in the direction of alternative help with meditation etc anything that can give a peace of mind. That he says, is primary to anyone and more importantly one with High BP and additionally one with menopause and depleted hormones. I have a huge huge sensitivity to drugs and he also carefully watches me. One of the last great family guys who knows his stuff and thinks outside the box as well. We are all individuals that react to disease processes and drugs so differently as is evident even here on this forum.

  10. Jane K.
    United States

    My doctor put me on losarten without much explanation. I already suffered from dry mouth from other medicines. The lower palate of my mouth became so sore with ulcers I could hardly stand it. I was even made to have a biopsy which was negative…I stopped the losarten and it cleared up on it’s own.. ????

  11. dee

    I have been taking losartan for six months. The muscle pain started gradually. I am now in so much pain that I can not walk without crutches. After reading about others reactions to losartan I can relate. Dry mouth vision change no sleep nightmares dizziness and confusion. Went back to the Dr. with complaints, she said I need more exercise and no pain no gain. I am appalled that Dr. would prescribe this med when side effects are so bad. I will end up in a wheelchair or worse if I continue this med. I think there should be a class action suit and then maybe doctors will be more careful with what they prescribe.

    • Bettye C.

      I am grateful that my husband is a holistic chiropractor and advanced nutritional response testing practitioner. Try and find one in your area and be tested. There are ways to help your muscle pain by covering the meds major side effects with products that are natural and then targeting the cause of the pain. There is a way. Have faith.

      We treat so many patients on these awful meds and they do so much better without decreasing them which we do not interfere with. Minerals deficient suddenly can be remedied. There are advanced compounds via decades old true blue supplements. But muscle testing with an advanced practitioner is key. Good luck.

    • Shelley

      I took Losartan for several months and have intense muscle pain. The doctor believes it’s an adverse side effect from the medicine. I have been off the medicine for two weeks now but I’m not seeing much improvement. It’s very painful to walk. Was wondering if your symptoms have improved or if you know if how long the side effects may last, or what if any remedy is there?

    • Sunny
      United Kingdom

      Hi Dee and all on Losartan. I have written previously on the horrible side effects. The lastest one being problems with my vision. About a month ago, while watching telly, I suddenly noticed that I had developed floaters in both eyes and that the left eye was every now and then giving me double visions.

      Iaw an ophthalmologist and he said I had dry eyes, which is so true and at times when I wake up in the mornings, my eyelids are stuck fast to the eye and I have to prise them open which does hurt. I have also been suffering from horrible flushes from head to nape area and sinus problems which give me terrible headaches and my cheekbones actually ache.

      Doctors I have consulted are only interested in changing the meds. By the way I have been on enalapril, then losartan and now cozaar SQ which is 50mg losartan and 5 mg amlodipine. Today, I just stopped taking it. I am going to try another doctor. Anyone has any suggestions ? Would really appreciate. By the way when doc put me on med because BP was at prehypertensive level. I do regret giving in to the doc’s persuasion to start it in the first place

  12. Pat W.

    Bummer! Now I’m worried. I’ve been on Benicar for 3-4 years now, with no problems or side-effects, but my new insurance doesn’t cover it, and just this past Monday my doctor switched me to Losartan 50mg. Pills arrived by mail today, and in searching the web, found this review of Losartan and I’m worried about even starting on this new to me medication.

  13. mary k

    As I read these comments it brings back horrible memories for me as I had a miserable time on these blood pressure medications. I am 82 and was put on these meds two years ago. A horrible two years for me. I found a natural way to be able to get off these meds and now my blood pressure is NORMAL with no pills. It can be done. Find a doctor for integrative medicine. There is one in Encinitas, California. Don’t just keep taking all of that stuff.

  14. mary k

    I would talk to your doctor about getting off the drugs. I was on both for a while and I felt as though I had been poisoned. Go to a naturopath doctor and get some natural help for HBP. Also, check to see if you might have sleep apnea as that causes HBP. It did for me. Now my BP is normal and I feel great and I no longer take any pharmaceuticals.

  15. TSK

    I have been on Losartan Pot 50mg since January. Since then, I really don’t feel like I’m sleeping but just dozing. At night, the muscle cramps in my legs are SO BAD that they are constantly waking me up. Also, have gained 10 pounds (no diet or other changes), I had maintained for over ten years a consistent weight. Has anyone else experienced these problems… I will definitely be looking to go back to Benzapril.

  16. ms

    My doctor has me on 50mg losartan potassium 2X daily. After my a.m. dose at about 6:00 I feel pretty good. However about 1:00p.m. I start getting anxious and get the ringing ear effect. I don’t want to take my p.m. dose until about 7:00 so that it will stay in my system thru the night. I also take 10mg buspar just before going to bed and sleep good. Hopefully these afternoon effects will gradually go away?? I have been on this 1 month.

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