What Medicines Cause Blood in Urine?

Several medicines can cause your urine to change color, or cause blood in your urine (hematuria). Certain antibiotics, NSAIDs, and other medicines cause blood in the urine.

Noticing blood in your urine or that your urine is pink, red, or brown may be scary, but it's not always a sign of kidney disease or something serious.

Several medicines can cause your urine to change color, or cause blood in your urine (hematuria). Blood in your urine can also be a sign of diseases like cancer and bleeding disorders. However, you should never take this symptom lightly as it can be a sign of something that can cause other health complications.

Your urine may have a red, pink, or brown color at times. Your urine may be a different color from blood, but other things may cause it, too.

Some things that can cause your urine to have a pink, red, or brown color include: 

• Artificial food colors
• Berries
• Beets
• Drugs that give a red color to your urine without any blood, like chloroquine, rifampicin, and furazolidone

Regular things like strenuous exercise or sexual activity can sometimes cause blood in your urine. Serious diseases like cancer and bleeding disorders may also show themselves first as hematuria.

To check if there is blood in your urine, your doctor may ask to test your urine. With actual hematuria, a microscopic examination may show red blood cells. Dipstick tests are commonly used to test for blood in the urine. These strips are dipped in urine, and the reagents in them react with the hemoglobin of blood to show a distinct color.

While your urine can look pink, red, or brown from food or have blood from a condition, blood in your urine can also be because of medicines rather than a disease.

Medicines can cause blood to appear in the urine in three ways: 

• Damage to the kidneys (conditions like interstitial nephritis and papillary necrosis)
• Bleeding from the urinary bladder (a condition called hemorrhagic cystitis)
• Bleeding because of stone formation

Drugs can either cause inflammation in the kidneys (interstitial nephritis) or damage to structures called renal papilla (papillary necrosis). Both these situations cause blood to appear in your urine.

Some drugs that can cause such damage include:

• Captopril
• Cephalosporins 
• Chlorothiazide 
• Ciprofloxacin
• Furosemide
• Non-Steroidal Anti Inflammatory Drugs (NSAIDs)
• Olsalazine 
• Omeprazole
• Penicillins 
• Rifampin 
• Trimethoprim-sulfamethoxazole (Septra) 

Stone formation in the kidneys, ureters, or urinary bladder (urolithiasis) can cause blood to appear in your urine. Only about 2% of renal system stones are caused by drugs, making this a rare cause.

Drugs that can cause blood in your urine by stone formation include: 

• Carbonic anhydrase inhibitors like acetazolamide
• Dichlorphenamide
• Indinavir and atazanavir
• Mirtazapine
• Ritonavir
• Triamterene

The blood in your urine is usually in minute amounts (microscopic hematuria), and you may not notice any color change. Your doctor may order a urine test because of other symptoms caused by the stones, like pain in your flank, nausea, and vomiting. You may also have a fever.

The laboratory would report if there is blood in your urine after microscopic examination.

If discolored urine or blood in your urine is caused by hematuria, your treatment would depend on how the medicine caused it. Your doctor may order you to stop taking your medication. It's important to note what medication caused hematuria so you can share that with doctors in the future, as you may want to avoid taking them.

Interstitial nephritis is an inflammation in the kidneys. Stopping the medicine causing it may reverse the inflammation. Your doctor may prescribe corticosteroids to cure the inflammation. Sometimes, stronger drugs like cyclophosphamide are needed.

Hemorrhagic cystitis needs a stoppage of the offending drug. Since many of these drugs are used for treating serious diseases, your doctor may prescribe an alternative medication. 

Your doctor may give you large amounts of liquids by mouth or IV infusion and drugs to make more urine. This process, called forced diuresis, reduces the exposure of your bladder to the drug causing bleeding. 

Stones in your urinary system often pass in the urine. This is very likely if the stone is less than 6 millimeters in size. Larger stones may have to be broken up by shock waves or removed by endoscopes or regular surgery. The drug that caused the stones may also be stopped or replaced with a different medication.

Seeing blood in your urine is not an automatic diagnosis of kidney disease. Several medicines for other conditions can cause this scary symptom. If you ever see blood in your urine, meet your doctor and tell them your other symptoms, as well as all the medicines you are taking.