the art of antibiotics

1. ANTIBIOTICS
• Antibiotics, also called antibacterial.
• They are a type of antimicrobial drug used in
the treatment and prevention of bacterial
infections.
• They may either kill or inhibit the growth of
bacteria.

2. TYPES OF ANTIBIOTICS
• Broad spectrum antibiotics: The term broad-spectrum
antibiotic refers to an antibiotic that acts against a wide
range of disease-causing bacteria.Examples are
ampicillin, Aminoglycosides (except for streptomycin) ,
Amoxicillin, Amoxicillin/clavulanic acid (Augmentin) ,
Carbapenems (e.g. imipenem) .
• Narrow spectrum antibiotics: a narrow-spectrum
antibiotic, which is effective against specific families of
bacteria. Azithromycin,Clarithromycin,Clindamycin,
Vancomycin.

3. CLASSIFICATIONS OF ANTIBIOTICS
Penicillins.
Cephalosporins .
Macrolides .
Fluoroquinolones
.
Sulfonamides.
Tetracyclines .
Aminoglycosides
.

4. PENICILLIN
• Sir Alexander Fleming discovered penicillin in
1928.
• It is obtained from culture media of mold,
fungi known as Penicillium notatum.
• The benzyl penicillin, procaine penicillin,
phenoxymethyl penicillin are commonly used
penicillins.
• It has been used as antibiotic

5. CLASSIFICATION OF PENICILLINS
Natural
penicillins
Semisynthetic
penicillins
Synthetic
penicillins
Broad
spectrum
Penicillin

6. NATURAL PENICILLINS
• The natural penicillins are obtained from
fungi Penicillium notatum and Penicillium
chrysogenum.
• The most common natural penicillin is Benzyl
penicillin –G.
• It is administered in the form of injections.
• Other example is procaine penicillin.

7. SEMISYNTHETIC PENICILLINS
• Semi synthetic penicillin is not destroyed by
stomach acidic content.
• The natural penicillins are got destroyed by
acidic secretions of the stomach.
• Example is Phenoxy methyl penicillin,
phenoxy ethyl penicillin, phenoxy propyl
penicillin.

8. SYNTHETIC PENICILLINS
• Penicillinase enzyme ( located in bacteria)
destroys the natural penicillins and semi
synthetic penicillins.
• So Synthetic penicillins are not destroyed by
penicillinase enzyme.
• Examples of synthetic penicillins are
Cloxacillin sodium, Oxacillin sodium,
Methicillin sodium.

9. BROAD SPECTRUM PENICILLIN
• Synthetic penicillins are effective only for
gram positive microorganisms.
• Therefore broad spectrum penicillin were
used.
• They are effective against both gram positive
and gram negative bacteria.
• Examples are Ampicillin, Hetacillin,
Carbencillin.

10. MECHANISM OF ACTION OF
PENICILLINS
• The penicillins are bactericidal antibiotics.
• They kill the bacteria by preventing their cell
wall formation.
• It is not so effective when the bacteria are
multiplying.

11. INDICATIONS OF PENICILLINS
• Crystalline penicillin is administered I/M , 4
hourly in severe infections and for mild
infections, dose can be reduced.
• Meningococcal meningitis infections.
• Actinomyosis and streptococcus sore throat.
• STD like syphilis and gonorrhoea.

12. SIDE EFFECTS OF PENICILLINS
• The high dose penicillins are nephrotoxic.
• The most common side effect is hypersensitivity.
The mild reaction may lead to urticarial, drug
fever.
• The most severe reaction is anaphylactic shock.
• Abscess may occur at the site of penicillin
injection due to irritation of the drug.
• Ampicillin may cause drug diarrhoea due to
continuous oral administration.

13. SPECIAL PRECAUTIONS
• Intradermal test or scratch test may be
performed first before the administration of
penicillins.

14. BENZYL PENICILLIN-G
Benzyl penicillin-G also known as crystalline penicillin-G,
penicillin-G.
It is obtained by growing strains of Penicillium notatum .
It is a natural penicillin antibiotic.
It is a white, crystalline, powder soluble in water, in
dextrose solution.

15. MECHANISM OF ACTION
It binds to specific penicillin-binding proteins
(PBPs) located inside the bacterial cell wall.
penicillin G inhibits the third and last stage of
bacterial cell wall synthesis.
They prevent the cell wall formation and
bacteria dies.

16. DOSAGE
• 0.5-5 million units IM or I.V. 6 hourly.

17. INDICATIONS
Septicaemia.
Meningitis.
Pericarditis.
Endocarditis.
Severe
pneumonia.
Ditherieria.
Gas
gangrene.

18. CONTRAINDICATIONS
• Avoid use of drugs if there is a history of
itching, urticaria, fever and sensitivity.

19. NURSING CARE
• To assess haematuria, oliguria since penicillin is nephrotoxic.
• Blood studies: WBC, RBC, Hb, BT,CT, Liver function test
• Bowel pattern during and after treatment.
• Respiration status, rate, wheezing, chest tightness, pain in the
chest.
• Oral penicillins to be administered empty stomach for best results.
• To evaluate absence of fever, and therapeutic response of the
treatment.
• The nurse has to assess allergic reaction before starting the
treatment.
• Skin eruptions on administration of penicillins and one week after
discontinuing of penicillin therapy.

20. AMPICILLIN
Ampicillin is a semi-synthetic derivative of penicillin .
It functions as an orally active broad-spectrum
antibiotic.
It is stable in acidic medium. It is very well absorbed
when administered orally.
It is white powder and soluble in water

21. MECHANISM OF ACTION
It binds to specific penicillin-binding proteins
(PBPs) located inside the bacterial cell wall.
It inhibits the third and last stage of bacterial
cell wall synthesis.
It prevents the cell wall formation and
bacteria dies.

22. INDICATIONS
• For treatment of infection (Respiratory, GI,
UTI and meningitis) due to E. coli, P. mirabilis,
enterococci, Shigella.

23. DOSAGE
Adults: 250-500 mg, 6 hourly.
Children: 125-250 mg, 6 hourly
Infants: 50 -150 mg

24. SIDE EFFECTS
Urticaria.
Drug
diarrhoea,
Skin rash.
Bone marrow
depression.
Nausea,
vomiting.
depression.

25. DRUG INTERACTION
• Penicillins decrease effectiveness of oral
contraceptives.
• Increase bleeding time.

26. AMOXYCILLIN TRIHYDRATE
• Amoxicillin is semisynthetic penicillin.
• It is effective against gram positive and gram
negative microorganisms.
• It can be administered without meals because
it is stable in gastric acid.
• It is white, crystalline powder.

27. DOSAGE
• Adult: 250 mg to 1 gram , 8 hourly.
• Children: 20 mg per kg body weight , 8 hourly.

28. MECHANISM OF ACTION
• Bactericidal: Inhibits synthesis of cell wall of
sensitive organisms, causing cell death.

29. INDICATIONS
• Infections due to susceptible strains of
Haemophilus influenza, Escherichia coli,
Neisseria gonorrhoea, streptococci, non–
penicillinase-producing staphylococci
• Helicobacter pylori infection in combination
with other agents
• Post exposure prophylaxis against Bacillus
anthraces

30. CONTRAINDICATIONS
• Contraindicated with allergies to penicillins,
cephalosporin, or other allergens.
• Use cautiously with renal disorders, lactation.

31. SIDE EFFECTS

32. DRUG INTERACTIONS
• Amoxicillin decreases effectiveness of oral
contraceptives.

33. CEPHALOSPORINS
• The cephalosporins are a class of β-lactam
antibiotics originally derived from the fungus
Acremonium.
• Cephalosporins are bactericidal (kill bacteria)
and work in a similar way to penicillins.
• They bind and block the action of
peptidoglycan which is a component of cell
wall.

34. CLASSIFICATION OF CEPHALOSPORINS
First
generation
cephalosporins
Second
generation
cephalosporins
Third
generation
cephalosporins
Fourth
generation
cephalosporins

35. FIRST GENERATION CEPHALOSPORINS
• These are useful against staphylococcal
infections.
• Examples are Cephazolin sodium,
Cephradine, Cephalridine, and Cephalothin.

36. SECOND GENERATION CEPHALOSPORINS
• The second generation cephalosporins act
against the staphylococcus and some of the
gram negative bacteria.
• This group includes Cefuroxime, Cefamandole
and Cefoxitin.

37. THIRD GENERATION CEPHALOSPORINS
• These injectable cephalosporins are effective
against gram negative bacteria.
• They have no action against staphylococci.
• The drugs are Cefotaxime, Cefsoludin, Cefdinir,
and Ceftriaxone.

38. CEFTRIAXONE
It is a third generation cephalosporins antibiotic.
It is available in the market under different trade
names like Cefaxone, Cefal etc.
Dosage: Adult 1 to 2 grams IV daily & 50 -75 mg
per kg body weight daily.
Indications: Septicaemia, typhoid, meningitis, UTI,
bone joint infections.

39. Action of mechanism
It inhibits cell-wall synthesis by
binding to 1 or more penicillin-
binding proteins.
It interferes with the synthesis of
peptidoglycan.

40. • Contraindications: Pregnancy and lactation
and hypersensitive to cephalosporins.
• Side effects: Headache, fever, chills, nausea,
vomiting, anorexia, nephrotoxicity.
• Nursing care: assess BUN, Creatinine.
Decreased urine output indicates
nephrotoxicity.

41. FOURTH GENERATION
CEPHALOSPORINS
• The fourth generation cephalosporins acts as
bactericidal.
• These drugs act at plasma binding proteins by
binding and disrupt the bacterial cell wall.
• It includes inj. Cefpirome, Inj Cefepime.

42. AMINO GLYCOSIDES
• Aminoglycosides are a class of antibiotics
used mainly in the treatment of aerobic gram-
negative bacilli infections.
• Though they are also useful against gram
positive bacteria.
• They are composed of amino sugars in
glycoside linkage.

43. • These groups following drugs:
1) Gentamycin.
2) Amikacin
3) Kanamycin
4) Tobramycin
5) Neomycin.
6) Sisomycin
7) Streptomycin

44. AMIKACIN
• It is a semi synthetic aminoglycoside.
• It is effective against gram negative bacilli.
• It is also used for the treatment of multidrug-
resistant tuberculosis.
• Availability: Injection AMEXEL, ZYCIN.
• Dosage: Adults : 15 mg per kg body weight .
In children 15 mg per kg body weight every 8-
12 hours daily.

45. • Actions: It binds ribosome sites thus prevents the protein
synthesis process.
• Indications: infections of respiratory tract, bones, joints,
skin, and soft tissue, CNS (including meningitis), peritonitis
burns, recurrent urinary tract infections (UTIs).
• Contraindications: Hypersensitive to amino glycosides,
lactation , pregnancy.
• Side effects: Skin rash, nephrotoxicity, ototoxicity,
tremors, headache, nausea, vomiting.
• Nursing care: Intake and output ratio of urinalysis daily be
noted. To watch for pulse rate change and hypotension.
Deafness should be noticed by audiometry testing.

46. QUINOLONES
• A quinolone antibiotic is any member of a
large group of broad-spectrum bactericides .
• They have a bicyclic core structure related to
the compound 4-quinolone.
• They are effective against both gram positive
and gram negative bacteria.

47. • Quinolones include following drugs:
1) Ciprofloxacin.
2) Levofloxacin
3) Lomefloxacin
4) Norfloxacin
5) Ofloxacin
6) Sparfloxacin
7) Nalidixic acid

48. CIPROFLOXACIN
• It is a fluroquinolone antimicrobial agent.
• It is effective against gram positive and gram
negative bacteria.
• It has significant post antibiotic effect due to
which it prevents regrowth of bacteria.
• Dose: Uncomplicated UTIs: 100–250 mg PO q
12 hr for 3 days or 500 mg PO daily (ER
tablets) for 3 days.

49. • Action : Ciprofloxacin promotes breakage of
double-stranded DNA in susceptible organisms
and inhibits DNA gyrase, which is essential in
reproduction of bacterial DNA.
• Indications: Uncomplicated UTIs, E. Coli
infection, Otitis externa ,STDs.
• Contraindications: Hypersensitive to
ciprofloxacin, renal impairment, epilepsy,
pregnancy, lactation, post-operative infections,
eye infections.

50. • Side effects: Vomiting , headache,
restlessness, rash, urticaria, blurred vision,
heart burn , chills.
• Nursing care: Allergy to ciprofloxacin,
Norfloxacin or other quinolones; renal
dysfunction; seizures; lactation , Arrange for
culture and sensitivity tests before beginning
therapy.

51. SULFONAMIDE
• Sulfonamides are the derivatives of Para
amino Benzoic acid (PABA) .
• These are also called as Sulfa drugs.
• Sulfa drugs were the first chemical substances
systematically used to treat and prevent
bacterial infections in humans.
• Now a days their use has been diminshed.

52. MECHANISM OF ACTION
• Para amino benzoic acid (PABA) is required for
growth and development of certain bacteria.
• When these drugs are administered , bacteria
is not able to differentiate between the Para
amino benzoic acid and Para amino benzene
sulfonamides .
• So folic acid synthesis is diminished.
• They act as bacteriostatic.

53. • Indications: UTI , ear infections, 90% effective
against the e.coli.
• Contraindications: Hypersensitivity to
sulfonamide, pregnancy , renal impairment,
skin and soft tissue and infections.
• Side effects: Nausea, vomiting, hepatitis,
glossitis, headache, confusion, anxiety,
bronchial asthma, urticaria, renal failure.

54. NURSING CARE
• Kidney function study : Blood urea, nitrogen,
Creatinine.
• To assess allergic reactions , urticaria, rash ,
dyspnoea.
• To assess intake and output ration.
• To assess sore throat, joint pain , fatigue.
• Culture and sensitivity tests.

55. TETRACYCLINE
• Tetracyclines are a class of antibiotics with
broad-spectrum activity .
• They are primarily bacteriostatic .
• It will not work for viral infections (e.g.,
common cold, flu). It will not work for colds,
flu, or other viral infections.

56. • Action: reversibly binds to the 30S ribosomal
subunit, preventing binding of tRNA to the
mRNA-ribosome complex, and thus interfering
with protein synthesis.
• Indications: Rocky Mountain spotted fever,
typhus fever and the typhus group, Q fever,
rickettsial pox and tick fever caused by
Rickettsiae. Respiratory infections.
Conjuctivitis, urethritis.

57. • Contraindications: Renal insufficiency, children
and allergic to tetracyclines.
• Side effects: nausea, vomiting, diarrhoea, upset
stomach, loss of appetite.
• Nursing care: Allergy to any of the tetracyclines;
hepatic or renal impairment, pregnancy,
lactation. Culture infection before beginning drug
therapy; many resistant strains have been
identified. Do not administer during pregnancy;
drug is toxic to the fetus.

58. MACROLIDES
• Macrolides are antibiotics which structure
contains a large lactone ring.
• It includes the following drugs erythromycin,
Polymxin B, Azithromycin, Clindamycin,
Lincomycin, Spiramycin, vancomycin,
spectinomycin, aztreonam, Roxithromycin.

59. ERTHRYOMYCIN
• Erythromycin is obtained from fungi
Streptomyces erythreus.
• It is a white or yellow crystals or powder ,
bitter in taste. It is less soluble in hot water.
• Erythromycin is available as 125 mg, 250 mg,
500 mg tablets, suspension 125 mg per 5 ml.

60. • Action: It acts on bacteria by inhibiting protein
synthesis by bacterial ribosomes. The bacteria
dies for lack of protein synthesis.
• Dosage: Adults 250 to 500 mg 6 hourly.Children:
25 to 50 mg per kg body weight . In adults for
gonorrhoea 500 mg daily every 6 hourly for 7
days.
• Indications: Acne vulgaris, upper respiratory
infections, acute pneumonia, vaginitis, eczema,
soft tissue infections.

61. • Contraindications: Hypersensitivity to
erythromycin, patient with a history of liver
disease.
• Side effects: Rash, urticaria, pruritis, nausea,
vomiting, hepatotoxicity, heartburn,
abdominal pain, stomatitis, vaginitis.

62. NURSING CARE
• To assess skin eruptions, itching.
• Assess intake and output ratio
• Liver studies(AST, ALT)
• Bowel pattern, before and during treatment.
• Renal studies.
• Culture and sensitivity before treatment.
• Not to take with fruit juice.