Z-Pak Side Effects
Generic name: azithromycin
Medically reviewed by Drugs.com. Last updated on Apr 10, 2023.
Note: This document contains side effect information about azithromycin. Some dosage forms listed on this page may not apply to the brand name Z-Pak.
Applies to azithromycin: oral powder for suspension, oral powder for suspension extended release, oral tablet. Other dosage forms:
Serious side effects of Z-Pak
Along with its needed effects, azithromycin (the active ingredient contained in Z-Pak) 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:
- loose stools
- Blistering, crusting, irritation, itching, or reddening of the skin
- cracked, dry, or scaly skin
- 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 or tightness
- cough increased
- cough producing mucus
- dark urine
- difficult or labored breathing
- difficult or painful urination
- dryness or soreness of the throat
- fast, irregular, pounding, or racing heartbeat or pulse
- general feeling of discomfort or illness
- 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
- sores, ulcers, or white spots on the lips or in the mouth
- stomach pain, continuing
- stomach pain, fullness, or discomfort
- stuffy nose
- swelling of the face, ankles, hands, feet, or lower legs
- tender, swollen glands in the neck
- 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
- Bleeding gums
- blood in the urine or stools
- blurred vision
- change in hearing
- clay-colored stools
- continuing ringing or buzzing or other unexplained noise in the ears
- decreased urine output
- diarrhea, watery and severe, which may also be bloody
- dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
- greatly decreased frequency of urination or amount of urine
- increased thirst
- loss of hearing
- lower back or side pain
- muscle twitching
- no blood pressure or pulse
- 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
- stomach cramps or tenderness
- stopping of heart
- unusual weight loss
Other side effects of Z-Pak
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:
- Acid or sour stomach
- aggressive or angry
- bad, unusual, or unpleasant (after) taste
- 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
- dry mouth
- excess air or gas in the stomach or intestines
- feeling of constant movement of self or surroundings
- full feeling
- increase in body movements
- itching of the vagina or genital area
- lack or loss of strength
- mental depression
- pain during sexual intercourse
- quick to react or overreact emotionally
- rapidly changing moods
- rash with flat lesions or small raised lesions on the skin
- redness of the skin
- sensation of spinning
- 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
For Healthcare Professionals
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 were diarrhea/loose stools, nausea, abdominal pain, and vomiting.[Ref]
Uncommon (0.1% to 1%): Palpitations, chest pain
Postmarketing reports: Torsades de pointes, arrhythmia (including ventricular tachycardia), ECG QT prolonged, hypotension, cardiovascular death
Common (1% to 10%): Rash, pruritus
Uncommon (0.1% to 1%): Angioedema, photosensitivity reaction, Stevens-Johnson syndrome, urticaria, dermatitis, dry skin, hyperhidrosis/sweating
Rare (0.01% to 0.1%): Acute generalized exanthematous pustulosis, drug reaction with eosinophilia and systemic symptoms (DRESS)
Frequency not reported: Eczema, fungal dermatitis, vesiculobullous rash
Postmarketing reports: Toxic epidermal necrolysis, erythema multiforme, serious skin reactions
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%), vomiting (up to 13%), flatulence (up to 10.7%), abdominal discomfort
Common (1% to 10%): Dyspepsia, stomatitis
Frequency not reported: Clostridioides difficile-associated diarrhea, melena, infantile hypertrophic pyloric stenosis, mucositis, enteritis
Postmarketing reports: Pyloric stenosis, pseudomembranous colitis, pancreatitis, tongue discoloration
Common (1% to 10%): Vaginitis/vaginal infection
Uncommon (0.1% to 1%): Dysuria, metrorrhagia, testicular disorder
Very common (10% or more): Decreased neutrophils (up to 29%)
Common (1% to 10%): Decreased lymphocyte count, decreased hematocrit, decreased hemoglobin, increased eosinophil count, increased platelet count, increased lymphocytes, increased basophils, increased monocytes, increased neutrophils
Uncommon (0.1% to 1%): Leukopenia, neutropenia, eosinophilia
Frequency not reported: Decreased white cell count, decreased platelet count, anemia
Hepatic failure has rarely resulted in death.
Common (1% to 10%): Increased AST, increased ALT, increased GGT, increased blood bilirubin
Uncommon (0.1% to 1%): Hepatitis, abnormal liver function tests
Rare (0.01% to 0.1%): Abnormal hepatic function, cholestatic jaundice
Frequency not reported: Liver enzyme abnormalities, increased transaminase levels, jaundice
Postmarketing reports: Hepatic failure, fulminant hepatitis, hepatic necrosis
Uncommon (0.1% to 1%): Hypersensitivity
Severe (rarely fatal) anaphylactic reaction has been reported.
Common (1% to 10%): IV site pain, injection site inflammation (with IV administration), IV site disorders (infection/inflammation/edema/pain reactions), local inflammation, infusion site reaction
Frequency not reported: Local inflammation at infusion site
Common (1% to 10%): Decreased blood bicarbonate, anorexia, decreased blood glucose, increased blood glucose
Uncommon (0.1% to 1%): Increased bicarbonate
Postmarketing reports: Dehydration
Common (1% to 10%): Arthralgia, increased creatine phosphokinase
Uncommon (0.1% to 1%): Osteoarthritis, myalgia, back pain, neck pain
Common (1% to 10%): Headache, dizziness, paresthesia, dysgeusia
Uncommon (0.1% to 1%): Somnolence, hypesthesia, tinnitus, vertigo
Frequency not reported: Hyperkinesia
Postmarketing reports: Syncope, convulsion, psychomotor hyperactivity, anosmia, ageusia, parosmia, myasthenia gravis, hyperactivity
Common (1% to 10%): Visual impairment, abnormal vision
Frequency not reported: Conjunctivitis, blurred vision
Very common (10% or more): Increased blood alkaline phosphatase (up to 20%)
Common (1% to 10%): Deafness, fatigue, increased potassium, increased lactate dehydrogenase, reversible hearing impairment
Uncommon (0.1% to 1%): Candidiasis/moniliasis, ear disorder, asthenia, malaise, chest pain, edema, hearing impaired, abnormal blood potassium, fungal infection, bacterial infection, hot flush, face edema, pyrexia/fever, pain, peripheral edema, increased chloride, abnormal sodium, postprocedural complications
Frequency not reported: Increased phosphate, decreased sodium, decreased potassium
Postmarketing reports: Hearing disturbances (including hearing loss, deafness, tinnitus)
Uncommon (0.1% to 1%): Nervousness, insomnia
Rare (0.01% to 0.1%): Agitation, depersonalization
Frequency not reported: Delirium, hallucination
Postmarketing reports: Aggression/aggressive reaction, anxiety
Common (1% to 10%): Increased blood urea/BUN, increased blood creatinine
Uncommon (0.1% to 1%): Renal pain
Frequency not reported: Nephritis, renal function abnormality
Postmarketing reports: Acute renal failure, interstitial nephritis
Common (1% to 10%): Dyspnea
Uncommon (0.1% to 1%): Pneumonia, pharyngitis, rhinitis, respiratory disorder, epistaxis
Frequency not reported: Bronchospasm, cough, pleural effusion
Frequently asked questions
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More about Z-Pak (azithromycin)
- Check interactions
- Compare alternatives
- Reviews (30)
- Dosage information
- During pregnancy
- Drug class: macrolides
Related treatment guides
1. Product Information. Zithromax IV (azithromycin). Pfizer U.S. Pharmaceuticals Group. 2022.
2. Product Information. Zithromax (azithromycin). Pfizer U.S. Pharmaceuticals Group. 2021.
3. Product Information. Zithromax (aziTHROMYCIN). Pfizer Australia Pty Ltd. 2022.
4. Product Information. Zithromax IV (aziTHROMYCIN). Pfizer Australia Pty Ltd. 2019.
5. Product Information. AziTHROMYCIN (Mylan) (aziTHROMYCIN). Alphapharm Pty Ltd. 2022.
6. Product Information. Zedbac (azithromycin). Aspire Pharma Ltd. 2022.
7. Product Information. Zithromax (azithromycin). Pfizer Ltd. 2022.
8. Product Information. Azithromycin (azithromycin). Sandoz Ltd. 2022.
9. Product Information. Azithromycin (azithromycin). Accord-UK Ltd. 2022.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
Some side effects may not be reported. You may report them to the FDA.