Losartan Side Effects
Some side effects of losartan may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.
For the Consumer
Applies to losartan: oral tablet
Get emergency medical help if you have any of these signs of an allergic reaction while taking losartan: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
In rare cases, losartan can cause a condition that results in the breakdown of skeletal muscle tissue, leading to kidney failure. Call your doctor right away if you have unexplained muscle pain, tenderness, or weakness especially if you also have fever, unusual tiredness, and dark colored urine.
Call your doctor at once if you have:
a feeling that you might pass out;
pain or burning when you urinate;
pale skin, feeling light-headed or short of breath, rapid heart rate, trouble concentrating;
wheezing, chest pain;
drowsiness, confusion, mood changes, increased thirst, loss of appetite, nausea and vomiting;
swelling, weight gain, feeling short of breath, urinating less than usual or not at all; or
high potassium (slow heart rate, weak pulse, muscle weakness, tingly feeling).
Common side effects may include:
cold or flu symptoms such as stuffy nose, sneezing, sore throat, fever;
pain in your legs or back;
stomach pain, diarrhea;
tired feeling; or
sleep problems (insomnia).
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.
For Healthcare Professionals
Applies to losartan: oral tablet
Losartan is generally well tolerated. The overall incidence of adverse experiences reported with losartan appears to be similar to placebo. Discontinuation of therapy due to adverse drug events has been reported in 2.3% of patients receiving losartan and 3.7% of patients receiving placebo.
General side effects reported postmarketing have included malaise.
Nervous system side effects have included headache (up to 14%), asthenia, fatigue, or dizziness (14%), and insomnia in 1% of patients. Single cases of reversible ageusia and migraine headache have been reported. Dysgeusia has been reported in postmarketing experience.
A single case of migraine headache has been associated with the use of losartan in a 50-year-old woman with hypertension and no history of migraine headaches or motion sickness. Her migraine headache resolved upon substitution with enalapril and recurred upon rechallenge with losartan.
Cardiovascular side effects have included dizziness in 3.5% (compared with 2.1% on placebo) and rare reports of first-dose orthostatic hypotension. It has also been reported that losartan generated signals for cardiac failure, pulmonary edema and peripheral ischemia. Fingernail clubbing has also been associated with the use of losartan. In addition, angioneurotic edema has been reported.
A 52-year-old man with a history of focal segmental glomerulosclerosis, hypertension, proteinuria, and an allergy to radiographic contrast material, who was taking bisoprolol-HCTZ and terazosin (captopril had been discontinued due to cough), developed a "scratchy throat", facial flushing, and swelling of the lips and right face within 30 minutes after a single 50 mg dose of losartan. There were no signs or symptoms of pulmonary edema. The patient recovered after diphenhydramine therapy.
Respiratory side effects have included cough; however, in contrast to the ACE inhibitors, the incidence of cough associated with losartan (3.4%) is similar to placebo (3.3%). One comparative study has shown that losartan reduces cough in patients who have a history of cough associated with ACE inhibitors. However, cases of cough, including rechallenges, have been associated with losartan use in postmarketing research. Upper respiratory tract infection has been reported in 7.9% of treated patients, compared with 6.9% with placebo. Nasal congestion has been reported in 1% to 2% of patients. Laboratory preparation of losartan (after pulverizing tablets) by pharmacists has resulted in bronchospasm.
Angiotensin II receptor blockade, unlike ACE inhibition, has no impact on the processing of peptides such as bradykinin and substance P, two peptides able to induce cough.
Intradermal and spirometry testing of the pharmacists who experienced bronchospasm during preparation of losartan (double-blinded, placebo-controlled, crossover study) revealed reproducible symptoms associated with decreased FEV1 measurements. Because of the small sample size, the spirometry results did not reach statistical significance.
Gastrointestinal complaints have been reported in less than 3% of patients, and have included loose bowel movements, dyspepsia, epigastric discomfort, and nausea. Dysgeusia, ageusia, and oral ulcers have been rarely reported. Acute pancreatitis has been reported.
A 49-year-old hypertensive woman was switched from enalapril to losartan because of fatigue. One week after starting losartan, the patient reported a persistent metallic taste, a tickling cough, and intestinal symptoms. Symptoms disappeared after discontinuation of losartan.
A 69-year-old hypertensive woman was switched to losartan from perindopril due to a tickling cough. A burning feeling on the tongue and a complete loss of taste developed three months after starting losartan. Perindopril was reinstituted and the taste disturbances disappeared within one week.
A 39-year-old hypertensive male was changed from enalapril to losartan because of a persistent cough. After one week, the patient complained of nausea, vomiting, and epigastric pain. Elevated amylase and lipase levels were noted. Five days after losartan was discontinued, laboratory values returned to normal. Gastrointestinal symptoms and elevated pancreatic enzyme values returned when losartan was reinstituted at a lower dosage.
Musculoskeletal side effects have included reports of pain, typically back or leg pain, in approximately 1% of patients, compared with 0% with placebo. In addition, rare reports of rhabdomyolysis have been reported during postmarketing experience in patients receiving angiotensin II receptor blockers.
Renal side effects have rarely included new or worsened renal insufficiency or hyperkalemia associated with decreased renal function. The net effects of losartan and the ACE inhibitors on renal hemodynamics and kidney function are similar. Minor increases in blood urea nitrogen (BUN) or serum creatinine have been reported (less than 0.1%). In addition, acute renal failure associated with losartan therapy has been reported in at least one patient with bilateral renal artery stenosis.
Rare cases of acute renal failure, including acute oliguric renal failure, have been associated with the use of losartan in patients who are susceptible to reduced renal plasma flow (e.g., decreased cardiac output, renal artery stenosis, preexisting renal insufficiency). Losartan causes only minor decreases in plasma aldosterone.
The increase in plasma renin activity associated with losartan is relatively small compared with those increases associated with ACE inhibitors. These blunted increases do not appear to affect the antihypertensive response to the antagonist.
In one study of patients with significant proteinuria and moderate renal insufficiency (average creatinine clearance greater than 60 mL/min), losartan 50 to 100 mg/day was associated with significantly increased renal plasma flow and significantly decreased urinary excretion of total protein, albumin, and immunoglobulin.
The pathogenesis of losartan-induced psychosis, if indeed it exists, is unknown. The author of this case report speculates that losartan may inhibit the enzyme enkephalinase, blocking the breakdown of the naturally-occurring opioid enkephalin. Opioids inhibit the release of substance P from primary sensory neurons. Perhaps, like ACE inhibitors, losartan might decrease plasma dopamine beta-hydroxylase concentrations.
Psychiatric side effects have included a single case of psychosis (reversible and reproducible on rechallenge of the drug) in an elderly woman with no personal or family history of mental illness or illicit drug use.
Metabolic side effects have included uricosuric effects and decreased serum uric acid levels. Animal data have shown that losartan may inhibit uric acid reabsorption in the proximal renal tubule, which can result in uricosuria and a small human trial demonstrated uricosuric effects. Cases of uric acid calculi have not been associated with the use of losartan or other angiotensin II receptor antagonists. Hyperkalemia and hyponatremia have also been reported.
Dermatologic side effects have rarely been reported and include dermatitis, dry skin, ecchymosis, erythema, flushing, pruritus, rash, sweating, and urticaria. Losartan has been implicated in several case reports of de novo development or exacerbation of psoriasis. Erythroderma has been reported in postmarketing experience.
Hypersensitivity reactions have been reported including angioedema with swelling of the larynx and glottis causing airway obstruction and/or swelling of the face, lips, and pharynx, and/or tongue.
A 77-year-old hypertensive male was prescribed 50 mg losartan a day. The patient mistakenly took losartan 50 mg three times a day for six weeks. Laboratory tests showed elevated serum creatinine, BUN, total bilirubin, AST, ALT, and GGT. Normalization of the laboratory values occurred within one month of discontinuing losartan.
Hepatic side effects have included occasional reports of increases in hepatic enzymes and serum bilirubin. Less than 0.1% of patients from large-scale controlled trials discontinued therapy due to increased liver function tests. Hepatitis has been reported rarely.
Hematologic side effects have included reports of small decreases in hemoglobin and hematocrit. In addition, anemia has been reported in renal transplant recipients (not having post-transplant erythrocytosis) treated with losartan. Losartan has also been implicated in a case of immune thrombocytopenia. Thrombocytopenia has been noted in postmarketing experience.
Immunologic side effects have included a case of Henoch-Schonlein purpura with a high titer of x-specific antineutrophil cytoplasmic antibodies (xANCA).
More losartan resources
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