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Naproxen Side Effects: What to Know

Last reviewed: March 2026

Overview

Naproxen shares side effects common to all NSAIDs, including stomach problems, cardiovascular risks, and kidney effects. While generally well-tolerated for short-term use, the longer half-life of naproxen means side effects may persist longer once they occur.

Common Side Effects

Gastrointestinal (most common):

  • Stomach upset or pain
  • Heartburn
  • Nausea
  • Constipation or diarrhea
  • Gas and bloating

Nervous system:

  • Headache
  • Dizziness
  • Drowsiness

Other common effects:

  • Fluid retention (mild swelling)
  • Ringing in ears (tinnitus)

Most common side effects improve as your body adjusts or resolve when you stop taking naproxen.

Serious Side Effects

Gastrointestinal Bleeding

Warning signs:

  • Black, tarry stools
  • Blood in vomit (may look like coffee grounds)
  • Severe stomach pain
  • Unexplained fatigue or weakness

Risk factors:

  • Age over 65
  • History of ulcers or GI bleeding
  • Concurrent use of blood thinners
  • Alcohol use
  • High doses or long-term use
  • Corticosteroid use

Important: GI bleeding can occur without warning symptoms.

Cardiovascular Events

Risks:

  • Heart attack
  • Stroke
  • High blood pressure
  • Heart failure worsening

Risk factors:

  • Existing heart disease
  • High blood pressure
  • Diabetes
  • High cholesterol
  • Smoking
  • Longer duration of use
  • Higher doses

Kidney Problems

Warning signs:

  • Decreased urination
  • Swelling in ankles or feet
  • Unusual fatigue
  • Unexplained weight gain

Risk factors:

  • Existing kidney disease
  • Dehydration
  • Older age
  • Use with ACE inhibitors or diuretics

Liver Problems

Warning signs:

  • Yellowing of skin or eyes (jaundice)
  • Dark urine
  • Severe fatigue
  • Upper right abdominal pain
  • Nausea

Severe Allergic Reactions

Symptoms:

  • Difficulty breathing
  • Swelling of face, lips, tongue, throat
  • Hives or severe rash
  • Chest tightness

Seek emergency care immediately if these occur.

Skin Reactions

Rare but serious:

  • Stevens-Johnson syndrome
  • Toxic epidermal necrolysis
  • Blistering or peeling skin
  • Widespread rash with fever

Stop naproxen immediately and seek medical care if severe skin reactions occur.

Side Effects by Body System

Digestive System

  • Stomach pain (3-9%)
  • Heartburn (3-9%)
  • Nausea (3-9%)
  • Constipation (3-9%)
  • Diarrhea (1-3%)
  • Ulcers and bleeding (rare but serious)

Cardiovascular System

  • Elevated blood pressure
  • Edema (fluid retention)
  • Palpitations
  • Heart attack, stroke (rare but serious)

Nervous System

  • Headache (3-9%)
  • Dizziness (3-9%)
  • Drowsiness (3-9%)
  • Difficulty concentrating

Skin

  • Itching
  • Rash
  • Bruising
  • Sweating

Ears

  • Tinnitus (ringing in ears)
  • Hearing changes

Managing Side Effects

Stomach Problems

  • Always take with food or milk
  • Avoid alcohol
  • Consider taking at bedtime with a snack
  • Ask doctor about stomach-protecting medications

Fluid Retention

  • Limit salt intake
  • Elevate legs when sitting
  • Report significant swelling to doctor

Drowsiness/Dizziness

  • Avoid driving until you know how naproxen affects you
  • Rise slowly from sitting or lying positions
  • Avoid alcohol

When to Stop and Seek Help

Stop naproxen and call your doctor if you experience:

  • Black or bloody stools
  • Vomiting blood
  • Severe stomach pain
  • Chest pain or shortness of breath
  • Weakness on one side of body
  • Slurred speech
  • Significant swelling
  • Signs of allergic reaction
  • Unexplained weight gain

Long-Term Use Considerations

With chronic use:

  • Regular monitoring of kidney function may be needed
  • Blood pressure checks important
  • Watch for signs of GI bleeding
  • Use lowest effective dose

Periodic reassessment:

  • Discuss ongoing need with healthcare provider
  • Consider drug holidays if appropriate
  • Monitor for cumulative effects

Increased risk with:

  • Other NSAIDs (don’t combine)
  • Aspirin or blood thinners
  • Corticosteroids
  • SSRIs
  • Alcohol

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