Note: This document contains side effect information about azithromycin. Some of the dosage forms listed on this page may not apply to the brand name Zithromax.

Common side effects of Zithromax include: diarrhea, loose stools, and nausea. Other side effects include: abdominal pain, and vomiting. See below for a comprehensive list of adverse effects.

Applies to azithromycin: oral powder for suspension, oral powder for suspension extended release, oral tablet

Other dosage forms:

• intravenous powder for solution

Along with its needed effects, azithromycin (the active ingredient contained in Zithromax) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking azithromycin:

More common

• Diarrhea
• loose stools

Less common

• Blistering, crusting, irritation, itching, or reddening of the skin
• cracked, dry, or scaly skin
• fever
• swelling

Rare

• Abdominal or stomach pain
• blistering, peeling, or loosening of the skin
• bloody or cloudy urine
• bloody, black, or tarry stools
• body aches or pain
• burning while urinating
• chest pain
• chills
• congestion
• cough increased
• cough producing mucus
• dark urine
• difficult or labored breathing
• difficult or painful urination
• dizziness
• drowsiness
• dryness or soreness of the throat
• earache
• fainting
• fast, irregular, pounding, or racing heartbeat or pulse
• general feeling of discomfort or illness
• general feeling of tiredness or weakness
• headache
• indigestion
• irregular or slow heart rate
• itching or rash
• joint or muscle pain
• large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
• light-colored stools
• loss of appetite
• muscle aches and pains
• nausea or vomiting
• noisy breathing
• passing of gas
• red skin lesions, often with a purple center
• red, irritated eyes
• redness or swelling in the ear
• runny nose
• shivering
• sneezing
• sores, ulcers, or white spots on the lips or in the mouth
• stomach pain, continuing
• stomach pain, fullness, or discomfort
• stuffy nose
• sweating
• swelling of the face, ankles, hands, feet, or lower legs
• tender, swollen glands in the neck
• tightness in the chest
• trouble with sleeping
• trouble with swallowing
• unpleasant breath odor
• unusual bleeding or bruising
• unusual tiredness or weakness
• upper right abdominal or stomach pain
• voice changes
• vomiting of blood
• yellow eyes or skin

Incidence not known

• Abdominal or stomach cramps or tenderness
• bleeding gums
• bloating
• blood in the urine or stools
• blurred vision
• change in hearing
• clay-colored stools
• coma
• confusion
• constipation
• continuing ringing or buzzing or other unexplained noise in the ears
• decreased urine output
• depression
• diarrhea, watery and severe, which may also be bloody
• dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
• fainting
• greatly decreased frequency of urination or amount of urine
• hives
• hostility
• increased thirst
• irritability
• lethargy
• loss of hearing
• lower back or side pain
• muscle twitching
• pains in the stomach, side, or abdomen, possibly radiating to the back
• pale skin
• pinpoint red spots on the skin
• puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
• rapid weight gain
• seizures
• stupor
• unusual weight loss

Some side effects of azithromycin may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Rare

• Acid or sour stomach
• aggressive or angry
• bad, unusual, or unpleasant (after) taste
• belching
• burning feeling in the chest or stomach
• burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
• change in taste
• changes in the color of the tongue
• crying
• depersonalization
• dry mouth
• dysphoria
• euphoria
• excess air or gas in the stomach or intestines
• feeling of constant movement of self or surroundings
• full feeling
• heartburn
• hyperventilation
• increase in body movements
• itching of the vagina or genital area
• lack or loss of strength
• mental depression
• nervousness
• pain during sexual intercourse
• paranoia
• quick to react or overreact emotionally
• rapidly changing moods
• rash with flat lesions or small raised lesions on the skin
• redness of the skin
• restlessness
• sensation of spinning
• shaking
• sleepiness or unusual drowsiness
• stomach upset
• thick, white vaginal discharge with no odor or with a mild odor
• white patches in the mouth, tongue, or throat

Incidence not known

• Difficulty with moving
• increased sensitivity of the skin to sunlight
• muscle pain or stiffness
• pain in the joints
• redness or other discoloration of the skin
• severe sunburn
• trouble sitting still

Applies to azithromycin: intravenous powder for injection, oral capsule, oral powder for reconstitution, oral powder for reconstitution extended release, oral tablet

The most commonly reported side effects include diarrhea/loose stools, abdominal pain, and nausea.

Very common (10% or more): Diarrhea (up to 52.8%), nausea (up to 32.6%), abdominal pain (up to 32.2%), loose stools (up to 19.1%), flatulence (up to 10.7%)

Common (1% to 10%): Vomiting, dyspepsia, stomatitis

Uncommon (0.1% to 1%): Gastroenteritis, oral candidiasis, constipation, dysphagia/oral dysphagia, abdominal distension, dry mouth, eructation, mouth ulceration, salivary hypersecretion

Frequency not reported: Pseudomembranous colitis, pancreatitis, tongue discoloration, melena, enteritis, abnormal stools, gastrointestinal disorder

Postmarketing reports: Pyloric stenosis

Common (1% to 10%): Decreased lymphocyte, hematocrit, hemoglobin, or neutrophil count, increased eosinophil count, increased platelets, hematocrit, lymphocytes, basophils, monocytes, or neutrophils

Uncommon (0.1% to 1%): Leukopenia, neutropenia/mild neutropenia, eosinophilia

Frequency not reported: Thrombocytopenia, anemia/hemolytic anemia, decreased platelets

Common (1% to 10%): Headache, dizziness, paresthesia, dysgeusia

Uncommon (0.1% to 1%): Somnolence, hypesthesia

Frequency not reported: Syncope, convulsion, anosmia, ageusia, parosmia, vertigo, myasthenia gravis, taste perversion, hyperkinesia

Postmarketing reports: Hyperactivity

Common (1% to 10%): Injection site pain, infection, edema, reactions or inflammation

Common (1% to 10%): Deafness, fatigue

Uncommon (0.1% to 1%): Candidiasis, ear disorder, asthenia, malaise, face edema, pyrexia, pain, post procedural complications, hearing disturbances/impairment, tinnitus, laboratory abnormalities, fungal or bacterial infection

Frequency not reported: Psychomotor hyperactivity, mucositis, fever, chills, otitis media

Postmarketing reports: Hearing loss, taste/smell perversion and/or loss

Common (1% to 10%): Rash, pruritus

Uncommon (0.1% to 1%): Photosensitivity reaction, Stevens-Johnson syndrome, urticaria, dermatitis, dry skin, hyperhidrosis, eczema

Very rare (less than 0.01%): Drug reaction of eosinophilia and systemic symptoms (DRESS)

Frequency not reported: toxic epidermal necrolysis, erythema multiforme, fungal dermatitis, sweating, vesiculobullous rash, maculopapular rash

Common (1% to 10%): Decreased blood bicarbonate, anorexia

Uncommon (0.1% to 1%): Abnormal sodium, increased blood alkaline phosphatase, bicarbonate, or chloride

Frequency not reported: Increased lactate dehydrogenase, decreased sodium or potassium

Postmarketing reports: Dehydration

Common (1% to 10%): Dyspnea

Uncommon (0.1% to 1%): Pneumonia, pharyngitis, rhinitis, respiratory disorder, epistaxis

Frequency not reported: Bronchospasm, cough, pleural effusion, asthma, bronchitis

Common (1% to 10%): Arthralgia

Uncommon (0.1% to 1%): Osteoarthritis, myalgia, back pain, neck pain

Frequency not reported: Increased creatine phosphokinase

Common (1% to 10%): Vaginitis/vaginal infection

Uncommon (0.1% to 1%): Dysuria, metrorrhagia, testicular disorder

Common (1% to 10%): Allergic reaction

Uncommon (0.1% to 1%): Angioedema, hypersensitivity

Frequency not reported: Anaphylactic reaction/anaphylaxis

Postmarketing reports: Fatal anaphylaxis

Common (1% to 10%): Visual impairment

Frequency not reported: Conjunctivitis

Uncommon (0.1% to 1%): Hepatitis, increased AST, ALT, GGT, or blood bilirubin

Rare (0.01% to 0.1%): Abnormal liver function tests, cholestatic jaundice

Frequency not reported: Hepatic failure/fatal hepatic failure, fulminant hepatitis, hepatic necrosis

Uncommon (0.1% to 1%): Palpitations, hot flush, edema, chest pain, peripheral edema

Frequency not reported: Torsades de pointes, arrhythmia, ECG QT prolonged, hypotension, ventricular tachycardia

Uncommon (0.1% to 1%): Nervousness, insomnia

Rare (0.01% to 0.1%): Agitation

Frequency not reported: Aggression/aggressive reaction, anxiety, delirium, hallucination, emotional lability, irritability, hostility

Uncommon (0.1% to 1%): Renal pain, increased blood urea nitrogen and creatinine

Frequency not reported: Acute renal failure, interstitial nephritis/nephritis

Frequency not reported: Moniliasis, flu syndrome