Generic Medicine Info
Indications and Dosage
Supplement in systemic therapy for treatment of susceptible infections
Adult: 500 mg daily.
Child: <10 yr Half of adult routine dosage.

Supplement in systemic therapy for treatment of susceptible infections
Adult: 500 mg daily.
Child: <10 yr Half of adult routine dosage.

Supplement in systemic therapy for treatment of susceptible infections
Adult: 500 mg daily.
Child: <10 yr Half of adult routine dosage.

Adult: 2 g 6 hrly.
Child: 150 mg/kg daily in divided doses.

Intrapartum prophylaxis against group B Streptoccocal infection in neonates
Adult: Initially, 2 g via IV inj followed by 1 g 4 hrly until delivery.

Biliary tract infections, Bronchitis, Endocarditis, Gastroenteritis, Listeriosis, Otitis media, Perinatal streptococcal infections, Peritonitis
Adult: 0.25-1 g 6 hrly.
Child: <10 yr Half of adult routine dosage.

Paratyphoid fever, Typhoid fever
Adult: 1-2 g 6 hrly for 2 wk in acute infections, and 4-12 wk in carriers.

Uncomplicated gonorrhoea
Adult: 2 g w/ 1 g of probenecid as single dose, recommended to be repeated in female patients.

Urinary tract infections
Adult: 500 mg 8 hrly.

Susceptible infections
Adult: 500 mg 6 hrly, via IM or slow IV inj over 3-5 min or by infusion.
Child: <10 yr Half of adult routine dosage.

Adult: 150-200 mg/kg daily. Initiate w/ IV admin for at least 3 days, then continue w/ IM inj 3-4 hrly. Continue treatment for at least 48-72 hr after the patient has become asymptomatic or when there is evidence of bacterial eradication. Recommended treatment duration for infections caused by group-A β-haemolytic streptococci: At least 10-days, to prevent occurrence of acute rheumatic fever or acute glomerulonephritis.
Child: Same as adult dose.
Renal Impairment
Patients undergoing haemodialysis should receive an additional dose after the session.
CrCl Dosage
<10 Dose reduction or increase in dose interval.
Should be taken on an empty stomach. Take 1 hr before or 2 hr after meals.
Add 1.5 mL water for inj to 500 mg vial contents.
Dissolve 500 mg in 10 mL water for inj. May be added to infusion fluids or injected, suitably diluted into the drip tube.
Dissolve 500 mg in up to 5 mL of water for inj or sterile procaine HCl 0.5% soln.
Dissolve 500 mg in up to 10 mL water for inj.
Dissolve 500 mg in 5-10 mL water for inj.
Incompatible w/ dextrose 5% in water, dextrose 5% in saline soln, dextrose 10% in water, fat emulsion 10%, hetastarch 6%, lactated Ringer's soln. Y-site: Amphotericin B cholesteryl sulfate complex, caspofungin, ciprofloxacin, epinephrine, fenoldopam, fluconazole, hydralazine, midazolam, nicardipine, ondansetron, sargramostim, verapamil, vinorelbine. Syringe: Erythromycin lactobionate, gentamicin, hydromorphone, kanamycin, lincomycin, metoclopramide.
Hypersensitivity to ampicillin and other penicillins.
Special Precautions
Patient w/ history of β-lactam allergy. Renal impairment. Pregnancy and lactation.
Adverse Reactions
Nausea, vomiting, diarrhoea, erythematous maculo-papular rashes, sore mouth, black/hairy tongue, rash, erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis, angioedema, fever, joint pains, serum sickness-like symptoms, haemolytic anaemia, thrombocytopenia, leucopenia, neutropenia, coagulation disorders, prolonged bleeding time and prothrombin time, CNS toxicity (e.g. convulsions); paraesthesia, nephropathy, interstitial nephritis, hepatitis, cholestatic jaundice, moderate and transient increase in transaminases.
Potentially Fatal: Anaphylaxis, Clostridium difficile-associated diarrhoea (CDAD).
IM/IV/Parenteral/PO: B
Monitoring Parameters
Monitor renal, hepatic, and haematologic function periodically; observe signs and symptoms of anaphylaxis during 1st dose.
Symptoms: Nausea, vomiting and diarrhoea. Management: Symptomatic and supportive treatment. May be removed from the circulation by haemodialysis.
Drug Interactions
May reduce the efficacy of OC. May alter INR while on warfarin and phenindione. May reduce the efficacy of oral typhoid vaccines. May reduce the excretion of methotrexate. Reduced excretion w/ probenecid and sulfinpyrazone, resulting to increased risk of toxicity. Allopurinol increases ampicillin-induced skin reactions. Reduced absorption w/ chloroquine. Bacteriostatic antibacterials (e.g. erythromycin, chloramphenicol, tetracycline) may interfere w/ the bactericidal action of ampicillin.
Food Interaction
Food decreases rate and extent of absorption.
Lab Interference
May interfere w/ diagnostic tests for urinary glucose using copper sulfate, direct antiglobulin (Coombs' test), tests for urinary or serum proteins and tests using bacteria (e.g. Guthrie test for phenylketonuria using Bacillus subtilis).
Description: Ampicillin inhibits bacterial cell wall synthesis by binding to 1 or more of the penicillin-binding proteins (PBPs) which in turn inhibit the final transpeptidation step of peptidoglycan synthesis in bacterial cell walls. Bacteria eventually lyse due to ongoing activity of cell wall autolytic enzymes (autolysins and murein hydrolases) while cell wall assembly is arrested.
Absorption: Moderately well absorbed from the GI tract (50%). Food may reduce rate and extent of absorption. Time to peak plasma concentration: Approx 1-2 hr.
Distribution: Widely distributed. Crosses the placenta and enters breast milk (small amounts). Plasma protein binding: Approx 20%.
Metabolism: Metabolised to some extent to penicilloic acid.
Excretion: Via urine as unchanged drug (oral: approx 20-40%; parenteral: approx 60-80%) w/in 6 hr and faeces (small amounts). Plasma half-life: Approx 1-1.5 hr.
Chemical Structure

Chemical Structure Image

Source: National Center for Biotechnology Information. PubChem Database. Ampicillin, CID=6249, (accessed on Jan. 20, 2020)

Store between 20-25°C. Reconstituted oral susp: Store between 2-8°C (discard after 14 days).
MIMS Class
Ampicillin 500 mg Capsules (Kent Pharmaceuticals Ltd). eMC. Accessed 02/07/2014.

Ampicillin 500 mg Vials for Injection (Essential Generics). eMC. Accessed 02/07/2014.

Ampicillin Injection, Powder, for Solution (APP Pharmaceuticals, LLC). DailyMed. Source: U.S. National Library of Medicine. Accessed 02/07/2014.

Ampicillin Suspension (Dava Pharmaceuticals). DailyMed. Source: U.S. National Library of Medicine. Accessed 02/07/2014.

Anon. Ampicillin. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. Accessed 03/07/2014.

Buckingham R (ed). Ampicillin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. Accessed 02/07/2014.

Disclaimer: This information is independently developed by MIMS based on Ampicillin from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2022 MIMS. All rights reserved. Powered by
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