Ampicillin + Flucloxacillin

Oral
Severe infections

Parenteral
Severe infections

Should be taken on an empty stomach. Take 30 min-1 hr before meals.

Parenteral:
IM: Add 1.5 mL water for inj to the vial. IV: Dissolve 500 mg in 10 mL water for inj. Administer by slow IV inj.

Incompatible w/ aminoglycosides. IV should not be mixed w/ other proteinaceous fluids (e.g. protein hydrolysates), IV lipid emulsions or w/ blood products.

Hypersensitivity to β-lactam antibiotics (e.g. cephalosporins, penicillins). Patient w/ history of flucloxacillin-associated jaundice/hepatic dysfunction; infectious mononucleosis; acute or chronic leukaemia.

Renal and hepatic impairment. Pregnancy and lactation.

Hypersensitivity reactions (e.g. rash, erythema multiforme, purpura, eosinophilia, angioneurotic oedema, fever, arthralgia, myalgia); GI disturbances, pseudomembranous colitis; hepatitis, cholestatic jaundice, transient elevation of liver enzymes; interstitial nephritis; leucopenia, thrombocytopenia.
Potentially Fatal: Anaphylaxis, Stevens-Johnson syndrome, toxic epidermal necrolysis.

Monitor renal and hepatic function esp during prolonged use.

Symptoms: GI effects (e.g. nausea, vomiting and diarrhoea). Management: Symptomatic and supportive treatment. Ampicillin may be removed via haemodialysis.

May reduce efficacy of oral contraceptives. Increased and prolonged serum levels of both ampicillin and flucloxacillin w/ probenecid. Increased risk of allergic skin reactions w/ allopurinol.

May cause false-positive result in glucose testing.

Description:
Mechanism of Action: Ampicillin exerts bactericidal action on both gm+ve and gm-ve organisms. Its spectrum includes gm+ve organisms e.g. Strep. pneumoniae and other Streptococci, L. monocytogenes and gm-ve bacteria e.g. M. catarrhalis, N. gonorrhoea, N. meningitidis, E. coli, P. mirabilis, Salmonella, Shigella, and H. influenzae. Ampicillin exerts its action by inhibiting the synthesis of bacterial cell wall. Flucloxacillin is bactericidal against penicillinase-producing and non-penicillinase-producing staphylococci. Its activity against streptococci e.g. Strep. pneumoniae and Strep. pyogenes is less than that of benzylpenicillin, but sufficient to be useful when these organisms are present w/ penicillin-resistant staphylococci.
Pharmacokinetics:
Absorption: Both are well absorbed from the GI tract and absorption is reduced by food. Peak plasma concentration: Ampicillin: Approx 1-2 hr; Flucloxacillin: Approx 1 hr.
Distribution: Both cross the placenta and small amounts are distributed into breast milk. Plasma protein binding: Ampicillin: Approx 20%; Flucloxacillin: Approx 95%.
Metabolism: Ampicillin: Metabolised to some extent to penicilloic acid.
Excretion: Ampicillin: Via urine approx 20-40% as unchanged drug (oral), 60-80% (parenteral); via bile and milk (in small amount). Flucloxacillin: Via urine approx 66% (oral), approx 76% (parenteral). Plasma half-life: Ampicillin: Approx 1-1.5 hr; Flucloxacillin: Approx 1 hr.

Store below 25°C. Reconstituted susp: Store at 2-8°C.

Penicillins

Anon. Ampicillin. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 06/09/2013.

Buckingham R (ed). Ampicillin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 06/09/2013.

Buckingham R (ed). Flucloxacillin. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 06/09/2013.

Co-fluampicil Capsules (Crescent Pharma Limited). MHRA. https://products.mhra.gov.uk/. Accessed 06/09/2013.

Co-Fluampicil Oral Suspension 125/125mg/5ml (Crescent Pharma Limited). MHRA. https://products.mhra.gov.uk/. Accessed 06/09/2013.

McEvoy GK, Snow EK, Miller J et al (eds). Ampicillin, Ampicillin Sodium, Ampicillin Trihydrate. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 06/09/2013.