Beta Lactam Antibiotics
Beta lactam antibiotics are composed of 5 different groups of antiboitics.
The antibacterial activity of beta lactam antibiotics ranges from narrow spectrum
to wide spectrum.
The first to be discovered and most widely used of all the antibiotics. Sir Alexander
Fleming first noted the action of the penicillium mould on Staphylococcus aureus
in 1928 and 1940 Florey and Chain isolated the active substance and produced a life-saving
Mode of action
- Cell walls are composed of peptidoglycan and to form it, sugars and peptides need
to be linked together by an enzyme called transpeptidase.
- Penicillin blocks the action of this enzyme so that when bacteria divide to make
new cells, the walls do not form correctly. They break and the bacterial cell is
- However, most S. aureus now produce penicillinase, so further modification of the
basic penicillin structure has produced antibiotics that can withstand penicillinase
and remain effective, e.g. methicillin.
- They penetrate into body tissues and fluids, except for the cerebrospinal fluid.
- They are excreted in high concentrations in the urine.
I] Penicillin G and Congeners
Benzothiazine Penicillin G
Procaine Penicillin G
Procaine + Benzothiazine Penicillin G
II] Beta Lactamase Resistant Penicillins
III] Extended-Spectrum Penicillins
IV] Extended-Spectrum Penicillins Plus Beta lactamase inhibitors
Amoxicillin + Clavulnate
Ampicillin + Sublactam
Piperacillin + Tazobactam
Ticarcillin + Clavulnate
Indications of use
- Streptococcal endocarditis
- Enterococcal endocarditis
- Staphylococcal endocarditis
- Benzylpenicillin (+low dose gentamicin).
- Amoxicillin (+low dose gentamicin).
- Flucloxacillin (+ gentamicin ).
- Sod. penicillin G injection: Benzyl Pen 0.5 , 1mU inj.
Available as dry powder in vial to be dissolved in sterile water.
- Procaine penicillin G injections : Procaine PenicillinG
0.5-1 MU dry powder in vial
0.5-1 MU I.M. 12-24 hrly as aqueous soln.
- Benzathine penicillin G Penidure La, Longacillin, Pencom, 0.6, 1.2, 2.4 MU
as dry powder in vial.
0.6- 2.4 MU I.M. every 2-4 weeks as aqueous suspension.
- Fortified procaine penicillin G injection: fortified PP inj. 3+1 lac U vial.
Contains 3lac unit procaine penicillin + 1lac unit Sod. penicillin G.
Hypersensitivity: Allergic reactions to any β-lactam antibiotic may occur in up
to 10% of patients receiving that agent. Anaphylaxis will occur in approximately
0.01% of patients.
- Serious reactions that can occur are:
- Diarrhaea that is watery or bloody.
- Fever, chills, body aches, flu symptoms.
- Easy bruising or bleeding, unusual
- Urinating less than usual or not at all.
- Severe skin rash,
itching, or peeling.
- Agitation, confusion, unusual thoughts or behaviour.
- Seizure (black-out or convulsions).
- Less serious reactions that are more likely to occur, such as:
- Nausea, vomiting, stomach pain.
- Vaginal itching or discharge.
- Swollen, black, or "hairy" tongue.
- Thrush (white patches inside your mouth or throat).
Local Irritancy and Direct Toxicity
- Pain at injection site, nausea on oral ingestion and thrombophlebitis on injected
vein are related expressions of irritancy.
- Toxicity of the brain may be manifested
as mental confusion, muscular twitchings, convulsions and coma, when large doses
>20MU are injected bleeding is also noticed.
Penicillinase Resistant Penicillins
Generic Name: Cloxacillin
Brand Name: Klox 0.25, 0.5 g cap,125 mg/3g dry syr, 0.25. 0.5g inj.
Bioclox, Clocilin 0.25, 0.5 g cap; 0,25, 0.5 g/vial inj.
- Gastrointestinal: Nausea, diarrhea, abdominal pain.
- Fever, seizure with extremely high doses and/ renal failure, rash (maculopapular
to exfoliative), vomiting, pseudomembranous colitis, vaginitis, eosinophilia, leukopenia,
neutropenia, thrombocytopenia, agranulocytosis, anemia, hemolytic anemia, prolonged
PT, hepatotoxicity, transient elevated LFTs, hematuria, interstitial nephritis,
increased BUN/creatinine, serum sickness-like reactions, hypersensitivity.
Extended-Spectrum Penicillins Beta lactamase inhibitors
Generic Name: Ampicillin
Brand Name: Ampilin, Roscillin, Biocilin 250, 500 mg cap; 125, 250mg/5ml dry cypr;
100mg/ml peadiatric drops.
- Urinary tract infection: ampicillin is the drug of choice.
- Respiratory tract
infection: including bronchitis, sinusitis, otitis media.
- It is the first line of treatment in Meningitis, Gonorrhoea.
and mixed infections.
- Sub-acute bacterial endocarditis.
- Bacillary dysentry and cholecystitis.
- Typhoid fever.
Diarrhoea is frequent after oral administration of ampicillin due to alteration
of the gut microbial flora.
It produces rashes, especially in patients with AIDS, BE virus infections or lymphatic
Patients with history of immediate type of hypersensitivity with PnG should not
be given ampicillin.
Generic Name: Amoxicillin
It is a close congener of ampicillin, similar in all aspects except that oral absorption
is better, incidence of diarrhoea is low.
Brand Name: Amoxylin, Novamox, Synamox 250, 500 mg cap, 125mg/5ml dry syr. Amoxil
,Mox 250,500 mg caps; 125 mg/5ml dry syr; 250, 500mg/vial inj.
Generic Name: Carbencillin
Brand Name: Carbelin 1g, 5g per vial inj
The important feature of this penicillin is its activity against Pseudomonas auruginosa
and indole positive Proteus not inhibited by PnG or aminopenicillins.
High doses are known to cause bleeding by interfering with platelet function.
Generic Name: Piperacillin
Brand Name: Piparfen 1g, 2g vials; Pipracil 2g, 4g vials for inj; contains 2mEq
Na+ per g.
It is mainly used in Neutropenic and immuno-compromised patients with serious gm-ve
Generic Name: Clavulanic acid
Mechanism of Action: It inhibits a wide variety of Beta lactamases produced by both
gm+ve and gm-ve bacteria but has no action of its own.
Coamoxiclav is indicated for
- Skin and soft tissue infection, intra abdominal and gynaecological sepsis, urinary,
biliary and respiratory tract infections and gonorrhoea.
Brand Name: Augmentin, Enhancin, Amonate: Amoxicillin 250mg + Clavulanic acid 125mg
tab; 1-2 tab TDS.
Augmentin: Amoxicilin 1g + Clavulanic acid 0.2g vial and 0.5 g + 0.1g vial; inject
1 vial deep I.M. or I.V. 6-8hrly.
Similar to amoxicillin.
Generic Name: Sulbactam
Semisynthetic Beta lactmase inhibitor.
Brand Name:Sulbacin; Ampitum: Ampicillin 1g + sulbactam 0.5g per vial inj.
Betamporal; Sulbacin 375mg tab.
- PPNG gonorrhoea, sulbactam per se inhibits N gonorrhoeae.
- Mixed aerobic and anaerobic infections, intra abdominal and gynaecological sepsis,
urinary, biliary and respiratory tract infections.
These are group of semi-synthetic antibiotics derived from 'cephalosporin -C'. They
are conventionally divided into 4 generations.
Mechanism of Action
All cephalosporins are bactericidal and have action similar to action of penicilin.
They inhibit the bacterial cell wall synthesis by binding to proteins different
from those that penicillins bind.
All cephalosporins exhibit common side effects.
- Pain after I.M. injection occurs with many. This is very severe with cephalothin
.Thrombophlebitis can occur on injection.
- Diarrhoea, due to alteration of gut
- Hypersensitivity caused by cephalosporins is similar to penicillins.
Rashes are more frequent, but anaphylaxis, angioedema, asthma, edema and urtricaria
may also occur.
- Cephalosporins show certain grade of nephrotoxicity. It is the highest with cephaloridine.
In a few cases it may be accentuated with previous renal disease.
- Bleeding occurs with cephalosporin.
- Neutropenia and thrombocytopenia have been reported with ceftazidime.
Generic Name: Cefazolin
Brand Name: Alcizon, Orizolin 0.25, 0.5 g, 1g per vial inj.
Dose- 0.25g 8hrly (mild case).
1g 6hrly (severe case) I.M. or I.V.
- Cefazolin is mainly used to treat bacterial infections of the skin.
- It can also be used to treat moderately severe bacterial infections involving the
lung, bone, joint, stomach, blood, heart valve and urinary tract.
- It is more active against Klebsiella and E.Coli.
- It is preferred cephalosporin in surgical prophylaxis.
Side effects from cefazolin are not common
Brand Name: Cephacilin 250, 500 mg cap, Sporidex, Cephaxin 250, 500 mg cap, 125mg/5ml
Amongst the multitude of possible indications the following should be mentioned
- Meningitis in neonates, children and adults (except pseudomonas infections).
Multiresistant Gram-negative infections, in particular caused by enterobacters.
Gonorrhoea caused by ß-lactamase producing gonococci (single dose of 250 mg I.M.).
Osteomyelitis caused by Staphylococcus aureus.
- Disseminated and persisting forms
of Lyme disease.
- Dose: 0.25-1g 6-8hrly. (children: 25-200mg/kg/day).
- Pain induration and tenderness at injection site area.
- May develop hematological
changes (eosinophilia, thrombocytosis, less frequently leucopenia).
- Diarrhoea,less frequently reported were nausea or vomiting, and dysgeusia. The onset
of pseudomembranous colitis symptoms may occur during or after antibacterial treatment.
Generic Name: Cephadrine
Brand Name: Ceflad 0.25, 0.5. 1g per vial inj.
Generic Name: Cefadroxil
Brand Name: Droxyl 0.5, 1g tab, 250mg/5ml sypr., Cefadrox 0.5 g cap,125mg/5ml sypr,
250 mg kid tab.
Brand Name: Cefogen, Supacef, Furoxil 250 mg and 750mg/vial inj, 0.75- 1.5 g I.M.
Generic Name: Cefuroxime Axetil
Brand Name: Ceftum, Spizef 125, 250, 500 mg cap tab and 125mg/5ml susp.
Generic Name: Cefaclor
Brand Name: Keflor, Vercef, Distaclor 250 mg cap, 125 and 250 mg Distab, 125mg/5mldry
syr, 50mg/mlped drops.
Generic Name: Cefotaxime
Brand Name: Omnatax, Oritaxim, Claforan 0.25, 0.5, 1.0 gm per vial inj.
- Prominent indication in meningitis caused by gram negative bacteria.
- Septiceamia and infection in immuno-compromised patients.
Dose: 1-2gm I.M. or I.V. 6-12 hly.
Generic Name: Ceftizoxime
Brand Name: Cefizox, Epocelin 0.5 -1g per vial inj.
Indication: similar to cefotaxime
Generic Name: Ceftriaxone
Brand Name: Oframax, Monocef , Monotax 0.25, 0.5, 1.0 g per vial inj.
Dose:1-2g I.V. or I.M. per day.
- Bacterial meningitis.
- Multi-resistant typhoid fever.
- Urinary tract
- Abdominal sepsis and septiceamia.
Hypoprothrombinemia and bleeding are specific adverse effects.
Generic Name: Ceftazidime
Brand Name: Fortum, Cefezid, Orzid 0.25, 0.5, 1.0 g per vial inj.
It is specifically used in febrile neutropenic patients with heamatological malignancies.
Neutropenia & thrombocytopenia, rise in plasma transaminases and blood urea
levels may be seen.
Generic Name: Cefaperazone
Brand Name: Magnamycin 0.25g, 1,2g inj ; Cefomycin, Nagaplus 1g inj; 1-2g I.M./I.V.12hrly.
Generic Name: Cefexime
Brand Name: Topcef, Orfix 100, 200 mg tab /cap. Cefspan 100 mg cap, 100mg/5ml syr.
Generic Name: Cefpodoxime proxetil
Brand Name: Cefoprox 100, 200 mg tab ,100mg/5ml dry syr; Cepodem 100, 200 mg tab,
Generic Name: Cefdinir
Brand Name: Sefdin, Adcef 300mg cap, 125mg/5ml susp.
Generic Name: Cefbuten
Brand Name: Procadax 400 mg cap, 90mg/5ml powder for oral susp.
Generic Name: Cefepime
Brand Name: Kefage 0.5, 1.0g inj.
Generic Name: Cefpirome
Brand Name: Cefrom, Ceforth 1g inj.
Carbapenems, Monobactams, Carbacephems
Generic Name: Imipenem
Is an extremely potent and very broad spectrum beta lactam antibiotic whose range
of activities includes gram positive cocci, enterobacteriaceae, Ps. aeuroginosa,
Listeria as well as anaerobes.
- It is commonly used in serious hospital acquired infections especially in cancer,
AIDS and neutropenic infections.
- Imipenem has the intensity to induce seizures in high doses.
Generic Name: Aztreonam
It inhibits gram negative enteric bacilli and H.influenzae at low concentrations
and Pseudomonas at moderate concentration.
- It is commonly used in serious hospital acquired infections originating from urinary,
biliary, gastroitestinal and female genital tract.
Generic Name: Loracarbef
The carbacephems are a new class of beta-lactam antibiotics that are similar in
structure to the cephalosporins. Carbacephems differ from cephalosporins, however,
in the substitution of a sulphur atom in the dihydrothiazine ring with a methylene
group to form a tetrahydropyridine ring. The result of this structural difference
is the carbacephem class.
- Loracarbef is indicated in the treatment of patients with mild to moderate infections
caused by susceptible strains of microorganisms such as S. pneumoniae, H. influenzae
(including b-lactamase-producing strains), M. catarrhalis, S. pyogenes, E.coli or
S. saprophyticus in conditions like lower and upper respiratory tract, pharyngitis,
tonsillitis, acute exacerbation of chronic bronchitis, urinary tract infections.
- All Patients
- Gastrointestinal: The most commonly observed adverse reactions were related to the
gastrointestinal system. The incidence of gastrointestinal adverse reactions increased
in patients treated with higher doses. Individual event rates included diarrhaea
4.1% ;nausea 1.9%; vomiting 1.4%; abdominal pain 1.4% and anorexia.
- Hypersensitivity: Hypersensitivity reactions include, skin rashes, utricaria and
- Central nervous system: Headache, dizziness and somnolence.
Heamatologi and lymphatic systems: Transient thrombocytopenia, leukopenia and eosinophilia.
Cardiovascular system: Vasodilatation.