INDIVIDUAL ANTIBIOTICS

INDIVIDUAL ANTIBIOTICS

PENICILLINS was 1st antibiotic to be used in man with revolution 3rd the Ht of injection.

Classification :•Penicillase sensitive penicillin

Penicillin GPenicillin V

•Penicillin resistant penicillin

•Methicillin

•Oxacillin

•Cloxacillin

•Nafcillin

•Broad spectrum penicillin

•Ampicillin

•Amoxicillin

•Bacampicillin

•Carbenicillin

•B lactamase inhibitors

•Clavulanic acid

•Salbactum

Source :

* The fungus penicillium notatum and related species produce naturally occurring penicillin.

•Semisynthetic penicillins are produced by chemically altering naturally occuring penicillins. It is done either by combining side chains or by incorporating specific precursors in the mould cultures.

Pharmacokinetics:•It may be administered orally or parenterally but should not be applied topically due to their allergic potential.

•Penetration of this antibiotic is poor in CNS. Bone, synovial, and pericardial fluid.

Drug Trade Names

Dosage form

Dose Indications Contraindications

Adverse effects

Tetracycline Achromycin

Terramycin

Capsule

Injection

Ointment

1-2 gm daily divided into 4 dose

Juvenile periodontitis, Chronic periodontal disease, Refractory periodontitis Desquamative gingivitis

Pregnancy Children below 8 years

Gl disturbance, tooth discoloration, enamel hypoplasia

Clindamycin Clincin

Dalcap

Tablet

Capsule

Injection

150-300 mg 6 hourly

Anaerobic streptococci, Clostridium infections, Refractory periodontitis

Hypersensitivity , infancy

Urticaria, diarrhea, abdominal pain, jaundice, liver abnormalities

Erythromycin Althrocin

Erythrocin

E. Mycin

Tablet 250-500 mg 8 hourly

Refractory periodontitis

Hypersensitivity

Mild epigastric pain, diarrhea, allergic reaction

Metronidazole Flagyl

Metroygyl

Aldezole

Tablet

Suspension

Injection

200-400 mg tds

200 mg/5 ml

Ulcerative gingivitis, periodontitis, ANUG

Neurological disease, blood dyscrasias, pregnancy

Anorexia, nausea, metallic taste, glossitis

Quinolone

Ciprofloxacin

Ciplox

Cipin

Tablet

Injection

250-500 mg 12 hourly

Osteomyelitis ANUG, joint infection, recurrent periodontitis

Hypersensitivity, children and elderly

Diarrhea, vomiting, abdominal pain, arthritis, restlessness

Penicillin

Amoxicillin

Ampicillin

Kaypen Ampilin,

Amox

Capsule, Syrup

250 mg-1 gm tds 125 mg/ml

Refractory periodontitis

Sensitivity Pregnancy

Skin rash, Urticaria, GIT upset, diarrhea

Cephalosporin

Cefotaxime

Cefaclor

Ceixime

Alcephin biotax

Capsule

Injection

Syrup

2-6 gm daily in 2-3 divided dose 4 gm initially followed by 2 gm IV

Inhibits growth of gram-ve anaerobes, Osteomyelitis

Hypersensitivity, Renal Failure

GIT upset Allergic reaction Increased SGPT candidiasis

Chlorhexidine

Hexidine

Rexidin

Suspension

0.2% w/v

100 ml

Oral hygiene becterial infection

Allergy to chlorhexidine

Burning sensation, candidiasis sensation, bad taste sensation staining of teeth

Antimicrobial Drugs :•In crosses the placental barrier and its metabolized in liver

• Excreted by tubular secretion and glomerular filtration.

Mechanism of Action :•It acts interfering with synthesis of bacterial cell wall.

• It is inactive against dormant organisms.;

• It inhibits the enzyme transpeptidases so that crosslinking( which maintains the close knit structure of the cell wall) dose not take place.

Antibacterial Spectrum :•Cocci-streptococci are highly sensitive. Pneumococci, Neisseria gonorrhoeae are also sensitive to penicillin.

• Bacilli-Corynebacterium dihitheriae, Clostridium tetani, Treponema Pallidum are sensitive to penicillin. Actinomyces israelii is only moderately sensitive.

• Gram negative bacilli-Mycobacterium tuberculosis. H. influenzae are sensitive to penicillin.

Bacterial Resistance :•The staphylococci that are present in a large number in hospital environment become resistant by producing penicilliase which inactivates penicillin by breaking the β-lactam ring.

• Some resistant bacteria become tolerant and not penicillin destroying.

Adverse Reaction :

Toxicity

* The margin of safety is very high when penicillin is administered.

With massive intravenous doses, direct central nervous system irritation can result in convulsions.

Large doses of penicillin G have been associated with renal damage manifested as fever, eosinophilia, rashes, albuminuria and rise in blood ura nitrogen.

Hemolytic anemia and bone marrow depression have also been induced by penicillin.

The Irritation caused by injection of penicillin can produce sterile abscesses, if given intramuscularly or thrombophlebitis, if given intravenously.

Anaphylactic reaction

• An acute allergic reaction occurs within ½ hour after the administration penicillin.

• It is characterized by smooth muscle contraction. Capillary dilation and urticaria caused by release of histamine and bradykinin..

• If treatment does not begin, immediately death can result.

•Rash- this type of reaction accounts for 80 to 90 percent of allergic reactions to penicillin.

• Delayed serum sickness-serum sickness is manifested as fever, skin rash and eosinophilia or severely as arthitis, purpura, lymphadenopathy.splenomegaly and edema. It usually takes 6 days to develop and can occur during treatment or up to 2 weeks after treatment has ceased.

• Oral lesion-delayed reaction includes severe stomatitis, furred tongue, black tongue, acute glossitis and cheilosis.

Penicillin G (Benzyl Penicillin)

It is active in low concentrations against all forms of gram +ve cocci and bacilli while in high concentrations it acts against gram –ve bacilli. It is available in various forms.

•Aqueous penicillin G* It is given intravenously for obtaining high serum concentration

and when large amount is needed. * The Half-life is 30 minutes. * Dose – 5 to 20 million units/per day intravenously often

continuously or at intervals of 2 to 4 hours.

•Procaine Penicillin G

•Low serum concentration gives good results

• Due to the presence of procaine the onset is slower, but prolonged.

•Used in meningits, syphilis and endocarditis.

•Dose-6 to 12 lac units intramuscularly every 12 to 24 hourly. In endocarditis 1.2 million units every 6 hourly is given.

Benzathine Penicillin G * It is used only when blood level is acceptable in patients with

rheumatic heart disease under-going long-term prophylaxis of bacterial endocarditis. * It is released over a period of a week after administration.

* Dose- 0.6 to 2.4 MU intramuscularly every 2 to 4 weeks as aqueous suspension.

Penicillin V•It differs from penicillin G only in that it is acid stable.•It can be given orally and produces higher blood level than penicillin G.• It is most commonly used in treatment and prevention of dental Infection. It can be given in pharyngitis, sinusitis, otitis media and prophylaxis of rheumatic fever.• Dose

• Adult – 250-500 mg 6 hourly•Infants – 60 mg 6 hourly.•Children – 125 to 250 mg 6 hourly.

Penicillinase Resistant Penicillin :

•They are resistant to degradation by staphylococcal penicillinase.

• They have a very narrow spectrum of action and primarily used for treatment

of Staphylococcus aureus infections such as soft tissue infection.

• Side effects are gastrointestinal disturbances, bone marrow depression. And

abnormal renal and hepatic function.

• Patients allergic to penicillin are also allergic to this group of drug.

• In serious infections methivillin and oxacillin are given IV 0.25 to 1 gm/4 hourly.

• In soft tissue infections cloxacillin is given orally 250 to 500 mg 6 hourly.

Broad Spectrum Penicillin

They are most resistant and they inhibit the cell wall synthesis. These are

used against large spectrum of bacteria.

Ampicillin and amoxicillin produce higher and prolonged blood levels.

Ampicillin

It is active against all organism sensitive to penicillin G in addition, many

gram-negative bacilli.

Oral absorption is incomplete but adequate. Food interferes with the

absorption.

Plasma half-life is 1 hour.

Adverse effects- diarrhea is frequent after oral administration. It

produces high incidence of rashes.

Dose – 0.5 to 2 g oral /i,m/iv depending on severity infection, every 6

hours.

Bacampicillin• It is an ester of ampicillin which is nearly completely absorbed from the

gastrointestinal tract.Thus. Higher plasma levels are attained.

• It does not markedly disturb intestinal ecology and due to incidence of

diarrhea, it is claimed to be lower.

•Dose – 400 to 800 mg bd.

Amoxicillin

* Oral absorption is better and food does not interfere

* Higher and more sustained blood levels are produced

* Dose – 0.25 to 1 g tds orally.

CHEPHALOSPORINS

These come under broad spectrum antibiotics. They are bactericidal

against gram +ve and –ve organisms. They inhibit cell wall synthesis of

bacteria.

Classification

First generation

Parenteral – cefazolin.

Oral –cephalexin, cefadroxil, cephradine

Second Generation

Parenteral – cefuroxime.

Oral –cefaclor, cefuroxime

•Third Generation

•Parenteral – ceftzidime, cefotaxime, ceftizoxime

•Oral - cefixime

•Fourth Generation

•Parenteral- cefpirome

Cefazolin

•Parenteral administration result in higher blood level that persists longer.

• It has a half-life of 2 hour due to slower tubular secretion

• Dose – 0.25 g 8 hourly (mild cases). 1 g 6 hourly(severe cases) IM and IV.

Cephalexin

•It is effective against most gram +ve cocci, baccilli, E. coli and Klebsiella.

• It is an orally effective first generation cephalosporin.

• Dose – 0.5 to 1 6 6 to 8 hourly and in children 25 to 100 mg/kg/day

Cefadroxil

It is close congener of cephalexin, has good tissue penetration and it exerts more sustained action at the site of infection.

Dose-0.5 to 1 g bd.

Cefaclor

It retains significant activity by the oral route.

It is more active against H. influenzae, E. coli.

Dose-125 oto 250 mg daily.

Cefuroxime

It is highly active against ampicillin resistant H. influenzae.

It is well tolerated by the IM route and attains relatively higher CSF level.

Dose-0.75 to 1.5 G IM 8 Hourly.

Cefixime It is an Orally active and is highly active against Enterobacteriaceae. Dose-200 to 400 mg bd.Uses : A. Dental Infection

1. It can be given as alternative to penicillin especially in patients allergic to penicillin

2. 1st and 2nd generation cephalosporin are active orally for orodental infection.3. It can be given for orodental infection mainly caused by klebsiella.4. Cephalexin and cephadroxil are given for prophylaxis of local wound infection following the dental surgery.

B. General Medical Use :1. As alternative of PnG in allergic patients 2. Respiratory, urinary, soft tissue infection caused by gram –ve 3. Septicaemias 4. Surgical Prophylaxis

AMINOGLYCOSIDES

It is a bactericidal drug and acts by inhibiting bacterial protein synthesis. They

have good activity against aerobic bacilli but also are active against anaerobic

bacteria. It can cause ototoxicity, nephrotoxicity and neuromuscular blockade.

Streptomycin

It is active against aerobic gram-negative bacilli.

Initially, it is used with rifampicin and isoniazid in treatment of tuberculosis

and with penicillin in treatment and prophylaxis of endocarditis.

Absorption from the injection site in muscles is rapid. It is excreted

unchanged in urine.

The plasma half-life is 2 to4 hours.

Adverse effects-there are vestibular and auditory disturbances. Pain at the

injection site is common.

dose-0.5 to 1 gm 12 hourly for 7 days in acute infection.

Neomycin It is a wide spectrum aminoglycoside, active against most gram-negative bacilli and some gram-positve cocci.

It is not used systemically, as it is highly toxic to the kidney. Oral and topical application does not cause systemic toxicity.

it is used topically for infected wound, ulcers, burns and external ear infection.

Dose-0.25 to 1 g qid oral and 0.3-0.5 percent topical.

Gentamicin It is useful in treatment of serious gram-ve bacterial infection.

Adverse reaction-nephrotoxicity, ototoxicity.

dose-for an average adult with normal real function 1 to 1.5 mg kg IM or IV 8 hourly should be given.

TETRACYSLINE

Broad-spectrum bacteriostatic antibiotic isolated from soil actinomycetes in 1948.

Action

It inhibits protein synthesis by binding to 30S ribosomes in susceptible organism.

It is effective against variety of gram-ve and gram +ve bacteria. Rickettsial, spirochetes, protozoa, and Mycoplasma.

It is mainly given orally and it is secreted in saliva, concentrated in liver and excreted in bile.

they cross placental barrier.

Dose-250 to 500 mg qid.

Adverse Reactions

GIT disturbances like anorexia, vomiting, diarrhea, gastroenteritis and superinfection.

Hepatic toxicity and renal toxicity can occur.

hypoplasia and brown discoloration of teeth can occur; hence it is not used in 3rd trimester.

tetracycline reduces protein synthesis and has an overall catabolic effect. They induce negative nitrogen balance and can increase blood urea level.

Tetracyclines are the most common antibiotics responsible for superinfection.

Uses :

Orodental Condition :

Tetracyclines are of limited usefulness in treating acute dental infection.

However they are benefit certain forms of periodontal disease.

Tetracycline plays important role in management of chronic periodontitis.

Tetracyclines are highly active against the Actinobacillus sp. That is held

responsible for destruction of gums and bone loss in juvenile periodontitis.

General Medical Uses :

Tetracycline are still the drug of first choice in –

a. Venereal disease

b. A typical pneumonia

c. Cholera

d. Plague

SULFONAMIDES These are bacteriostatic drugs which inhibit bacterial folate synthesis hence folic acid is not formed and number of essential metabolic reactions suffer. It is effective against gram +ve and gram –ve bacteria like streptococcus pyogenes, Actinomyces and H. influenzae. They are distributed throughout the body including the cerebrospinal fluid and it is metabolized in liver and excreted in urine. Adverse reactions

There may be allergic reaction in the form of urticaria, poruritus, fever, polyarteritis nodosa, erythema multiforme and Stevens-Johnson syndrome. Sulfonamides can cause hemolysis. Topical use of sulfonamides in not recommended because of risk of contact sensitization. There may be nausea, vomiting and epigastric pain.

Dose Sulfadiazine-0.5 g qid to 2 g tds. Sulfamoxole-1 g bd on first day then 0.5 gm bd.

ERYTHROMYCIN It is isolated from streptomyces erythreus in 1952.

It is bacteriostatic and interferes with protein synthesis by inhibiting enzyme transferase at the 50S subunit of ribosome.

It is effective against gram +ve and gram –ve bacteria.

It is used as prophylaxis against endocarditis before dental procedures and in patients allergic to penicillin. It is also used in tertanus, diphtheria and syphilis.

It is excreted through urine, faeces and bile.

Adverse reactions- there may be stomatitis, abdominal pain, nausea, vomiting, jaundice, diarrhea, urticaria, and anaphylaxis.

Dose-it is given orally in dose of 250 to 500 mg 8 hourly.

CLINDAMYCIN It is a lincosamide antibiotic. They are bacteriostatic and effective against gram +ve bacteria. It is mainly used against anaerobic bacteria.

Oral absorption of clindamycin is good. It poenetrates most skeletal and soft tissues.

It crosses placental barrier and excreted in urine and bile.

Adverse reactions- there may be pseudomembranous enterocolitis, severe persistent diarrhea. Passage of blood and bloody stool, skin rashes, dizziness, nausea and vomiting.

Dose-150 to 300 mg qid orally and 200 to 600 mg IV 8 hourly

VANCOMYCIN It is a glycopeptide antibiiotic. It is a bactericidal agent which is active against gram +ve cocci and bacilli.

It acts by inhibiting bacterial cell wall synthesis.

It is not absorbed orally. After IV administration, it is widely distributed, penetrates serous cavities, inflamed meninges and is excreted by glomerular filtration.

Adverse reaction- it can cause plasma concentration dependent nerve deafness which may be permanent.

Dose-250 to 500 mg 6 hourly orally and 500 mg 6 hourly or 1 g 12 hourly injected IV.

METRONIDAZOLE Metronidazole in a dose of 200-400 mg TDS (15-30 mg/kg/day) is extensively used to treat orodental infections, because anaerobic bacteria are frequently involved.

After entering the microorganisms by diffusion, its nitro group is reduced to intermediate compounds which cause cytotoxicity, probably by damaging DNA.

It should be avoided during first trimester of pregnancy, blood dyscrasias.

Adverse reactions- there may be nausea, anorexia, epigastric pain, headache, metallic taste, glossitis, stomatitis and hairy tongue. Patient may get peripheral neuropathy and CNS effects.

Dose- 200-400 mg/8 hourly orally, 15 mg/kg body weight 6 hourly IV.