Unasyn Side Effects

Generic name: ampicillin / sulbactam

Medically reviewed by Drugs.com. Last updated on Mar 1, 2024.

Note: This document provides detailed information about Unasyn Side Effects associated with ampicillin / sulbactam. Some dosage forms listed on this page may not apply specifically to the brand name Unasyn.

Applies to ampicillin / sulbactam: injection powder for solution.

Common side effects of Unasyn

Some side effects of ampicillin / sulbactam 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:

More common side effects

• bleeding, blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site

Rare side effects

• excess air or gas in the stomach or intestines
• full or bloated feeling
• general feeling of discomfort or illness
• headache
• passing gas
• pressure in the stomach
• redness, swelling, or soreness of the tongue
• swelling of the abdominal or stomach area
• white patches in the mouth or throat or on the tongue
• white patches with diaper rash

Incidence not known

• burning feeling in the chest or stomach
• indigestion
• stomach upset

Serious side effects of Unasyn

Along with its needed effects, ampicillin / sulbactam 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 or nurse immediately if any of the following side effects occur while taking ampicillin / sulbactam:

Less common side effects

• changes in skin color
• diarrhea
• pain, tenderness, or swelling of the foot or leg

Rare side effects

• bloody nose
• burning while urinating
• chest pain, discomfort, or pressure
• chills
• decrease in the frequency of urination
• decrease in urine volume
• difficulty in passing urine (dribbling)
• flushing or redness of the skin
• painful urination
• swelling
• swelling or puffiness of the face
• tightness in the throat
• unusually warm skin

Incidence not known

• abdominal or stomach cramps or tenderness
• black, hairy tongue
• blistering, peeling, or loosening of the skin
• bloating
• cough or hoarseness
• cracks in the skin
• diarrhea, watery and severe, which may also be bloody
• fever
• fever with or without chills
• general feeling of tiredness or weakness
• increased thirst
• itching
• joint or muscle pain
• loss of heat from the body
• lower back or side pain
• nausea or vomiting
• pain
• red, irritated eyes
• red, swollen skin
• scaly skin
• severe stomach pain
• sore throat
• sores, ulcers, or white spots on the lips or in the mouth
• swelling or inflammation of the mouth
• unusual bleeding or bruising
• unusual tiredness or weakness
• unusual weight loss
• vomiting

For healthcare professionals

Applies to ampicillin / sulbactam: injectable powder for injection.

General adverse events

This drug was generally well-tolerated.^[Ref]

Local

• Very common (10% or more): Pain at IM injection site (16%)
• Common (1% to 10%): Pain at IV injection site, thrombophlebitis, phlebitis
• Postmarketing reports: Injections site reaction^[Ref]

Gastrointestinal

• Common (1% to 10%): Diarrhea
• Uncommon (0.1% to 1%): Nausea, vomiting, flatulence, abdominal distension, glossitis
• Frequency not reported: Pancreatitis, enterocolitis, pseudomembranous colitis
• Postmarketing reports: Gastritis, stomatitis, black "hairy" tongue, Clostridium difficile associated diarrhea^[Ref]

Hypersensitivity

• Frequency not reported: Hypersensitivity reactions to ampicillin (including urticarial rash, edema, hypotension, fever, eosinophilia, dyspnea, delayed hypersensitivity maculopapular rash, anaphylaxis, interstitial nephritis, Henoch-Schonlein purpura, focal glomerulonephritis, Stevens-Johnson syndrome)
• Postmarketing reports: Serious and fatal hypersensitivity (anaphylactic) reactions^[Ref]

Dermatologic

• Common (1% to 10%): Rash
• Uncommon (0.1% to 1%): Itching, facial swelling, erythema
• Frequency not reported: Ampicillin-associated bullous pemphigoid, linear IgA dermatosis, pseudoporphyria
• Postmarketing reports: Erythema multiforme, toxic epidermal necrolysis, Stevens-Johnson syndrome, acute generalized exanthematous pustulosis, urticaria, exfoliative dermatitis^[Ref]

Hematologic

• Frequency not reported: Decreased hemoglobin, decreased hematocrit, decreased red blood cells, decreased white blood cells, decreased neutrophils, decreased lymphocytes, decreased platelets, increased lymphocytes, increased monocytes, increased basophils, increased eosinophils, increased platelets, thrombocytopenia, leukopenia, red cell aplasia, anemia, atypical lymphocytosis
• Postmarketing reports: Hemolytic anemia, thrombocytopenic purpura, agranulocytosis, positive direct Coombs test^[Ref]

Hemolytic anemia, thrombocytopenic purpura, and agranulocytosis were generally reversible when therapy was discontinued; may be hypersensitivity events.^[Ref]

Nervous system

• Uncommon (0.1% to 1%): Headache
• Frequency not reported: Seizures, neurotoxic potential, worsening myasthenia gravis symptoms
• Postmarketing reports: Convulsion^[Ref]

Seizures have been reported in very ill patients with high serum levels of ampicillin. High cerebral spinal fluid (CSF) levels of some penicillins are potentially neurotoxic; the CSF levels of ampicillin rise significantly in meningitis.^[Ref]

Hepatic

• Frequency not reported: Increased AST, increased ALT, hepatitis, prolonged cholestasis
• Postmarketing reports: Cholestatic hepatitis, cholestasis, hyperbilirubinemia, jaundice, abnormal hepatic function^[Ref]

Metabolic

• Frequency not reported: Increased alkaline phosphatase, increased lactate dehydrogenase, decreased serum albumin, decreased total protein^[Ref]

Genitourinary

• Uncommon (0.1% to 1%): Urine retention, dysuria
• Frequency not reported: Urinary red blood cells, urinary hyaline casts^[Ref]

Renal

• Frequency not reported: Increased BUN, increased creatinine
• Postmarketing reports: Tubulointerstitial nephritis^[Ref]

Other

• Uncommon (0.1% to 1%): Candidiasis, fatigue, malaise, chest pain, edema, chills, substernal pain, mucosal bleeding^[Ref]

Respiratory

• Uncommon (0.1% to 1%): Throat tightness, epistaxis

Further information

Unasyn side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer