Antibiotics. Introduction Contents 1. Sulfonamides 2. Penicillin's 3. Cephalosporin's 4. Macrolides...
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- Slide 1
- Antibiotics
- Slide 2
- Introduction Contents 1. Sulfonamides 2. Penicillin's 3.
Cephalosporin's 4. Macrolides 5. Quinolones/Fluoroquinolones 6.
Aminoglycosides 7. Tetracycline's 8. Miscellaneous Drugs
- Slide 3
- Continue Antibiotics are drugs of pertaining ability to destroy
or interfere with the development of a living organism. Antibiotics
can be classified into: 1. Bacteriostatic 2. Bactericidal
- Slide 4
- Sulfonamides Sulfonamides are chemically related group of
antibiotics that are all synthetic derivatives of sulfonamide. They
were one of the first group of drugs used as antibiotics and some
of the more commonly prescribed agents.
- Slide 5
- Continue These antibiotics achieve very high concentration in
kidneys through which they are eliminated. There fore they are
primarily used for the treatment of urinary tract infections (UTI).
Sulfonamides are also used in the treatment of rheumatoid
arthritis, in addition they may be combined with other antibiotics
to increase their antibiotic potency.
- Slide 6
- Drugs Sulfadiazine Sulfamethiazole Sulfamethoxazole
Sulfisoxazole Sulfadimidine Sulfametopyrazine
- Slide 7
- Chemistry
- Slide 8
- Sulfapyridine
- Slide 9
- Mechanism of action Sulfonamides donot actually destroy
bacteria but inhibit their growth. They inhibit the growth of
susceptible bacteria by preventing the synthesis of folic acid. The
enzyme dihydrofolic acid DHF, synthase converts para- amino benzoic
acid PABA to DHF, which subsequently converts into tetrahydrofolic
acid THF.
- Slide 10
- Therapeutic Uses Sulfonamides are used for the treatment of: 1.
Urinary tract infections caused by, enterobacter spp, klebsiella
spp, proteus vulgaris, & staphylococcus aureus. 2. Nocardiosis
3. Infected burns and leg ulcers (silver sulfadiazine) 4.
Inflammatory bowel disease (sulfasalazine)
- Slide 11
- Side-effects Headache Convulsion Aplastic anemia Nausea
Vomiting Diarrhea Toxic nephrosis
- Slide 12
- Sulfamethoxazole Sulfamethoxazole is an intermediate acing
sulfonamide antibiotic. Because it is eliminated by means of
kidneys and reaches very high concentrations there, it is commonly
used to treat urinary tract infections caused by susceptible
organisms. It is combined phenazopyridine (analgesic) that affects
the mucosa of UTI.
- Slide 13
- Continue Sulfamethoxazole by it self comes as a 500mg/5ml oral
suspension and 500mg tablet. It is a pregnancy category C.
- Slide 14
- Co-trimaxazole Co-trimaxazole is a combination of
Sulfamethoxazole and Trimethoprim. The optimum synergistic in vitro
effect against most susceptible bacteria is achieved with 5: 1
ratio of Sulfamethoxazole and trimethoprim. Has an half life of 10
hour. Used for UTI caused by susceptible bacteria, pneumocystis
carinii pneumonia. Used for ear infection (otitis media) Used for
bronchitis Used for STD including gonorrhea and syphilis.
- Slide 15
- Continue Available 40mg/5ml oral suspension Available 80mg
trimethoprim & 400mg Sulfamethoxazole= 480mg co-trimaxazole.
Available 180mg trimethoprim & 800mg Sulfamethoxazole = 980mg
co-trimaxazole. Available 16mg/ml trimethoprim & 80mg/ml
Sulfamethoxazole= 96mg/ml injection.
- Slide 16
- Sulfisoxazole Sulfisoxazole is a short acting sulfonamide
antibiotic that is primarily used urinary tract infections. Used
for ear infection (otitis media) in small children. It is a
pregnancy category C agent. Available 500mg tablet & 500mg/5ml
suspension.
- Slide 17
- Penicillin's The penicillin's are very large group of
chemically related antibiotics that are derived from a fungus or
mold, often seen on bread or fruit. The penicillin's may also be
called beta-lactam, a term which refers to their chemical
structure.
- Slide 18
- Continue The penicillin's was first introduced on the market in
the early 1940 and to this day they have remained very effective
and safe antibiotics. They are bactericidal and can kill a wide
variety of gram positive bacteria Half life of penicillin's is 2h
approximately.
- Slide 19
- Classification of drugs The penicillin's can be divided into:
1. Natural penicillin's 2. Penicillinase resistant penicillins 3.
The amino-penicillins 4. The extended spectrum penicillin's
- Slide 20
- Mechanism of action Penicillin's involves several steps that
together result in the inhibition of bacterial cell wall synthesis.
They block penicillin binding proteins (PBP), by inhibiting
peptidoglycan in the cell wall bacteria.
- Slide 21
- Side-effects Anemia Lethargy Bone-marrow depression
Hallucination Nausea Vomiting Sore throat Abdominal pain
- Slide 22
- Natural Penicillin's Natural penicillin's are: 1. Pen G 2. Pen
V 3. Pen M 4. Pen N 5. Pen X 6. Pen F
- Slide 23
- Penicillin G
- Slide 24
- Penicillin V
- Slide 25
- Penicillin G Penicillin G consists of: 1. Benzathine 2.
Potassium 3. Sodium 4. Procaine
- Slide 26
- Penicillin G Benzathine Given IM injection Long acting drug
Expected to work over the course for several days.
- Slide 27
- Penicillin G K + & Na Commonly administered IV for the
treatment of life threatening illnesses such as: 1. Septicemia 2.
Meningitis 3. Pericarditis 4. Severe pneumonia
- Slide 28
- Aminopenicillins There are three aminopenicillins: 1.
Amoxicillin 2. Ampicillin 3. Bacampicillin Because of the presence
of a free amino group on the penicillin's nucleus, the
aminopenicillins have enhanced activity against gram negative
bacteria.
- Slide 29
- Continue Amoxicillin is an analogue of ampicillin and
becampicillin is a prodrug of ampicillin. The aminopenicillins are
contraindicated: 1. Hypersensitivity They are rated in a pregnancy
category B drugs.
- Slide 30
- Amoxicillin
- Slide 31
- Ampicillin
- Slide 32
- Ampicillin is the prototypical amino penicillin, that has amino
group. It is available in three different forms: 1. Anhydrous 2.
Trihydrate 3. Sodium Anhydrous and trihydrate Ampicillin are
administered orally.
- Slide 33
- Continue Ampicillin sodium is given parenterally. Available
250mg, 500mg capsules, 250mg/5ml suspension, 125, 250, 500, 1000,
2000, 10,000mg vial for injection. Adult dosage is PO: 250mg- 500mg
Qid, IM/IV: 250mg- 500mg Qid.
- Slide 34
- Penicillinase Resistant Penicillin's These congeners have side
chains that protect the beta-lactam ring from attack by
staphylococcal penicillinase. However this also partially protects
the bacteria from the beta lactam ring. Their only indication is
infectious caused by penicillinase producing staphylococci, for
which they are the drugs of choice except in areas where
methicillin resistant staph aureus (MRSA) has become
prevalent.
- Slide 35
- Methicillin It is highly penicillinase resistant but not acid
resistant, must injected. it is also an inducer of penicillinase
production. The MRSA have altered PBPs which donot bind
penicillins. The drug of choice for these organisms is
vancomycin/linezolid, but ciprofloxacin can also be used.
Haematuria, albuminuria, and nephritis are the side effects of
methicillin.
- Slide 36
- Cloxacillin It has an isoxazolyl side chain and is highly
penicillinase as well as acid resistant. It is more active than
methicillin against penicillinase producing staph. Cloxacillin is
incompatibly but dependably absorbed from oral route, especially if
taken in empty stomach. Plasma half life is about 1 hour.
Elimination occurs primarily by kidney, also partly by liver. It is
available 0.25g, 0.5g cap and injections.
- Slide 37
- PROCAINE PENICILLIN ALLERGIC REACTION ID/CC: A 21 year old male
comes to the health clinic because of the development of fever,
marked itching all over his body, generalized rash with joint
swelling and difficulty breathing. HPI: he just returned from a
trip abroad, where he had developed a purulent urethral discharge
and went to a local doctor who gave him two pills of procaine
penicillin. PE: mild hypotension, mild cyanosis and difficulty
breathing. Imaging: CXR is normal
- Slide 38
- Continue Treatment: Subcutaneous epinephrine, oxygen,
hydrocortisone, antihistamines. Maintain airway and provide
assisted ventilation if necessary. Severe reactions may result in
laryngeal obstruction, hypotension and death.
- Slide 39
- Continue Discussion: Penicillins are antimicrobial drugs that
block cell wall synthesis by inhibiting peptidoglycan cross
linking; they are bactericidal for gram positive cocci and rods,
gram negative cocci. Most adverse reactions to penicillin are
allergic reactions that result when one of it is metabolites acts
as hapten. Anaphlytic reaction involves antigen reacting with IgE
on presensitized mast cells and basophils, it is usually severe and
immediate.
- Slide 40
- METHICILLIN RESISTANCE STAPHYLOCOCCUS AUREUS (MRSA) ID/CC: A 25
year old male presents with spiking fevers, malaise, left sided
chest pain and cough. HPI: His symptoms started two weeks ago and
have progressively worsened despite a full course of oral
antibiotics. He also reports a history of prior IV drug abuse.
PE:VS: Fever (39 centigrade), tachycardia (HR 105), tachypnea. PE:
amphoric, breath sounds heard over left lower lobe; S1 & S2
normally heard without murmurs, gallops or rubs. Labs: induced
sputum cultures grew methicillin resistant staphylococcus aureu.
Imaging: XR, chest: 2 by 3cm cavity in left lower lobe of lung with
air fluid level. CT, chest: confirmed a left lower lobe lung
abscess.
- Slide 41
- Continue Treatment: Intravenous Vancomycin therapy, add
aminoglycoside for synergistic bactericidal effect. Discussion:
Antibiotic resistant is continuing to increase in both the hospital
and the community. Major resistant nosocomial organisms include
s.aureus, klebsiella, and pseudomonas. MRSA is becoming widespread
in a number of communities and is more commonly seen in IV drug
abusers, patients with recent hospitalizations.
- Slide 42
- Cephalosporin's The cephalosporin's are semi-synthetic
antibiotic derivatives of cephaloporin C. These chemically altered
derivatives of this fungus are broadly referred to as
cephalosporin's and they are structurally and pharmacologically
related to the penicillin's. Cephalosporin's have a broad spectrum
of bacteria.
- Slide 43
- Continue The safety profiles, contraindications and pregnancy
ratings of cephalosporin's are very similar to those of
penicillin's. Because of cephalosporin's are chemically very
similar to penicillin's, a person who has had an allergic reaction
to penicillin's have also allergic reaction in cephalosporin's,
this is referred to as cross sensitivity.
- Slide 44
- Continue Cephalosporin's of all generations are very safe
agents that are categorized as pregnancy category B agents. They
are contraindicated: 1. Hypersensitivity 2. Younger than 1 month
old
- Slide 45
- Classification of Drugs Cephalosporin's can be classified into:
1. First generation 2. Second generation 3. Third generation 4.
Fourth generation
- Slide 46
- First Generation Drugs 1. Cefazolin sodium 2. Cephalothin 3.
Cephalexin 4. Cephradine 5. Cephapirin
- Slide 47
- Continue First generation are usually active against gram
positive bacteria and have limited activity against gram negative
bacteria. They are available both parenteral and oral.
- Slide 48
- Cefazolin sodium First generation of cephalosporin Excellent
coverage against gram positive and poor coverage of gram negative.
Only available in parenteral formulation that comes 500- 1000mg
vials for IM or IV injection. Adult dosage is IM/IV: 250mg-1g
q8h-q12h.
- Slide 49
- Second Generation Drugs 1. Cefamandole 2. Cefoxitin 3.
Cefuroxime 4. Cefonicid 5. Ceforanide 6. Cefmetazole 7. Cefaclor 8.
Cefprozil
- Slide 50
- Continue The second generation cephalosporin's have similar
coverage against gram positive organisms but enhanced gram negative
bacteria. They include both parenteral and oral formulations. The
second generation cephalosporin's are also excellent prophylactic
antibiotics.
- Slide 51
- Continue The qualities that make them excellent prophylactic
agents are: 1. Safety profile 2. Broad range of organisms they can
kill 3. Relatively low cost
- Slide 52
- Cefoxitin It is a parenteral second generation cephalosporin.
Cefoxitin has been used extensively as a prophylactic antibiotic in
patients undergoing such surgical procedures especially in
abdominal and colorectal operations. It is rated pregnancy category
B. Available only in parenteral formulations 1,2, 10g vials for
injection
- Slide 53
- Third Generation Drugs 1. Cefoperazone 2. Cefotaxime 3.
Ceftizoxime 4. Ceftriaxone 5. Ceftazidime 6. Cefixime
- Slide 54
- Continue Third generation cephalosporin's are the most potent
in fighting gram negative bacteria.
- Slide 55
- Ceftriaxone Ceftriaxone is a parenterally administered third
generation cephalosporin that differs from the other agents in that
it has a very long half life that allows it to be given once a day.
It can be given both intravenously and intramuscularly. It can
easily pass meningitis and BBB, making it an excellent agent for
the treatment of CNS infection.
- Slide 56
- Continue Available 250, 500mg, 1, 2, 10 gram vials. Adult
dosage is: IM/IV 1-4 g/day as a single dose or divided doses.
- Slide 57
- Tetracycline's The tetracycline's are small chemically related
group of five antibiotics, three of which are naturally occurring
and two of which are semi-synthetic. They are derivatives of
streptomyces organisms. Tetracycline's can only inhibit the growth
of bacteria, they cannot kill bacteria, therefore they are
considered bacteriostatic.
- Slide 58
- Chemistry of Tetracycline
- Slide 59
- Continue The three naturally occurring tetracycline's are: 1.
Tetracycline 2. Demeclocycline 3. Oxytetracycline The two
semi-synthetic tetracycline's are: 1. Doxycycline 2.
Minocycline
- Slide 60
- Mechanism of action Tetracycline's work by inhibiting protein
synthesis 30S in susceptible bacteria.
- Slide 61
- Therapeutic uses Chlamydia Syphilis Lyme Rickettisiae Protozoa
Acne Cholera Shigellosis Mycoplasma pneumonia
- Slide 62
- Side-effects Discoloration of teeth Tooth enamel hypoplasia
Retard fetal skeletal development Photosensitivity Alteration of
the intestinal flora Diarrhea Gastric upset Reduced bacterial
vitamin K synthesis
- Slide 63
- Doxycycline Doxycycline is a semi synthetic tetracycline
antibiotic. Doxycycline comes in the following three different salt
forms: 1. Calcium 2. Hyclate 3. Monohydrate
- Slide 64
- Continue It is useful in the treatment of rickettsial
infections, gonorrhea and many gram negative infections. It comes
orally as a 25 and 50mg/5ml oral suspension, 50, 100mg capsules and
100, 200mg per ml injections. It is rated in a pregnancy category D
drug.
- Slide 65
- TETRACYCLINE RASH ID/CC: A 19 year old red haired female visits
her dermatologist at a local clinic because of a rash that appeared
after she spent the sunny weekend hiking without sun block
protection. HPI: Two months ago, her dermatologist put her on the
low dose tetracycline to prevent acne. PE: Normal Labs: Mild
proteinuria
- Slide 66
- Continue Treatment: Sun protection, both mechanical and
pharmacological, while taking tetracycline. Discussion:
Tetracyclines are bacteriostatic antibiotics that bind to 30s
ribosomal subunit, blocking synthesis of protein. If they are taken
with alkaline foods such as milk and antacids, GI absorption is
decreased. Tetracyclines are used therapeutically and
prophylactically for chylamdial infections, lyme disease, acne and
cholera.
- Slide 67
- Aminogylcosides Aminoglycosides are group of natural and
semi-synthetic antibiotics that destroy bacteria, rather than
inhibit their growth, so they are bactericidal. They are derived
from streptomyces organisms. They are not given orally because of
their poor oral absorption.
- Slide 68
- Continue They can kill both gram positive and gram negative
bacteria but are customarily used to kill gram negative such as,
pseudomonas, E. coli and klebsiella. The aminogylcosides work in a
way that is similar to that of tetracycline's in that they also
bind to ribosomes and thereby prevent protein synthesis in
bacteria.
- Slide 69
- Continue The aminogylcosides have been shown to cross the
placenta and cause fetal harm when administered to pregnant women.
The pregnancies categories of the various aminogylcosides are as
follows: 1. Gentamycin, neomycin: pregnancy category C 2.
Tobramycin,Amikicin,kanamycin:pregnancy D 3. Streptomycin:
pregnancy category B
- Slide 70
- Drugs Gentamycin Tobramycin Amikacin Kanamycin Neomycin
Streptomycin
- Slide 71
- Mechanism of action Aminoglycosides kill bacteria by binding
and disrupting protein synthesis in bacteria specifically they do
this by binding to both 30s and 50s ribosomal subunit.
- Slide 72
- Side-effects Renal failure Hearing loss (Ototoxicity) Nausea
Vomiting Proteinuria Increase serum creatinine level
- Slide 73
- Gentamycin Gentamycin is a naturally occurring aminoglycoside
that is obtained from cultures of micromonospora purpurae. It is
one of the Aminoglycosides most commonly used in clinical practice
today. It is classified pregnancy category C. Available 10, 40mg/ml
injection IM/IV, 10, 60, 80 mg per ml intravenous infusion.
- Slide 74
- Continue Available 3% solution or ointment for ophthalmic.
Comes also 0.1% ointment for topical application on: 1. Superficial
skin infection 2. Burns 3. Skin ulcers
- Slide 75
- GENTAMICIN SIDE EFFECTS ID/CC: A 34 year old women presents
with her family practitioner complaining of hearing loss, vertigo
and inability to walk properly due to lack of balance. HPI: she
took IV Gentamicin for 10 days PE: Well hydrated, oriented and
cooperative Imaging: normal
- Slide 76
- Continue Treatment: Discontinuation of the drug, supportive
therapy. Discussion: Gentamicin is an aminoglycoside and thus
shares the Ototoxicity and Nephrotoxicty of streptomycin,
kanamycin, Amikacin, and tobramycin. Ototoxicity is mainly cochlear
and marked by ataxia and vertigo. Nephrotoxicity is minimized if
care is taken to hydrate the patient and keep serum levels
therapeutic.
- Slide 77
- Quinolones The quinoline antibiotics are very potent broad
spectrum antibiotics. They are bactericidal The first of these
agents to come available were: 1. Cinoxacin 2. Nalidixic acid
- Slide 78
- Continue The newer quinoline antibiotics include: 1.
Norfloxacin 2. Ciprofloxacin 3. Enoxacin 4. Ofloxacin 5.
Lomefloxacin 6. Perfloxacin
- Slide 79
- Continue A fluorine atom was added on to the basic quinolone
structure to create these newer agents and increased their
anti-bacterial activity. Because of chemical, these agents are
sometimes called fluoroquinolones.
- Slide 80
- Continue The fluoroquinolones are active against a wide variety
of gram negative and selected gram positive bacteria.
Fluoroquinolones are primarily excreted by the kidneys, which
contain a high percentage of unchanged drug, this makes them good
for treating of UTI.
- Slide 81
- Continue Their use in children is not currently recommended
because they have been shown to suppress growth in laboratory
animals.
- Slide 82
- Mechanism of action Quinolone antibiotics destroy bacteria by
altering DNA and they accomplish this by interfering with DNA
gyrase, enzyme necessary for the synthesis of bacterial DNA, if
bacteria cannot produce DNA they die.
- Slide 83
- Side-effects Dizziness Insomnia Fatigue Nausea Rash Fever
Blurred vision
- Slide 84
- Ciprofloxacin Ciprofloxacin was one of the first potent
fluoroquinolones to come available. First marketed in an oral form
and advantage of convenience of oral preparation plus excellent
bioavailability. Effective against to kill gram negative bacteria.
Orally comes 250, 500, 750mg tablet, parenterally comes 200, 400mg.
The common dosage is 250mg-750mg Tid, Bid.
- Slide 85
- FLUOROQUINOLONE SIDE EFFECTS ID/CC: A 21 year old college
baseball player restarted his training 3 days ago, running 1600
meters a day in preparation for the upcoming state tournament,
yesterday he hit a home run and started off to first base when he
suddenly fell to the ground and couldnt work due to acute pain.
HPI: He had spent 4 weeks in the hospital recovering from
perforated appendicitis where he received IV ciprofloxacin for 2
weeks due to surgical wound infection with pseudomonas aeruoginosa
that was resistant to all other antibiotics.
- Slide 86
- Continue PE: Surgical wound completely healed with no evidence
of infection or postincisional hernia; penrose drain orifice within
normal limits; inability to plantarflex left foot; Achilles tendon
completely severed. Labs: CBC: no leukocytosis; no anemia. SMA-7
normal. UA: normal. Imaging: CXR/KUB: within normal limits. Micro
Pathology: Achilles tendon shows inflammatory neutrophilic
infiltrate with areas of heamorrhage and necrosis.
- Slide 87
- Continue Treatment: Surgical repair. Discussion:
Fluoroquinolones such as ciprofloxacin and Norfloxacin are
bactericidal antibiotics that are active against gram negative
rods, including pseudomonas; they are also active against Neisseria
and some gram positive organisms. They act by binding DNA gyrase.
Side-effects include damage to cartilage, tendonitis, and tendon
rupture; they also produce gastric upset and nausea and may cause
super infection.
- Slide 88
- Macrolides The Macrolides are a large group of antibiotics that
first came available in the early 1950s with the introduction of
erythromycin. Macrolides have a macrocyclic lactone. Macrolides are
considered bacteriostatic but in high concentration may be
bactericidal in some susceptible bacteria. Macrolides are POM
drugs. Macrolides are rated pregnancy category C.
- Slide 89
- Drugs Azithromycin Clarithromycin Erythromycin Troleandomycin
Roxithromycin
- Slide 90
- Erythromycin
- Slide 91
- Clarithromycin
- Slide 92
- Azithromycin
- Slide 93
- Mechanism of action They bind 50s ribosomal subunit inside the
cells of bacteria and by doing so prevent the production of the
bacterial protein needed for bacteria to grow, with the result that
bacteria eventually will die.
- Slide 94
- Antibacterial spectrum It is narrow, includes mostly gram
positive and a few gram negative bacteria. It is highly active in
the following bacteria's: 1. str. pyogenes 2. Str. Pneumoniae 3. N.
gonorrhoeae 4. Clostridia 5. C. dipthteriae
- Slide 95
- Uses 1. As an alternative to penicillin: streptococcal
pharyngitis, tonsillitis, community acquired respiratory infections
caused by pneumococci and H. influenzae, however many bacteria
resistant to penicillin are also resistant to erythromycin. 2.
Diphtheria: erythromycin 250mg Qid, acute stage as well as for
carriers 7 day treatment, antitoxin is the primary treatment.
- Slide 96
- Continue 3. Tetanus: erythromycin 500mg is given Qid for 10
days to eradicate clostridium tetani. 4. Syphilis and gonorrhea 5.
Atypical pneumonia caused by mycoplasma pneumoniae 6. Whooping
cough: 1 to 2 week course of erythromycin is the most effective
treatment for eradicating Pertussis from upper respiratory
tract.
- Slide 97
- Continue 7. Chlamydia trachomatis infection of urogenital
tract: erythromycin 500mg QID for 7. 8. Penicillin resistant
staphylococcal infections 9. Helicobacter pylori infection:
Clarithromycin 500mg in combination in Omeprazole 20mg, and
amoxicillin 1g each administered twice a day for 10 to 14 days, is
effective for the treatment of peptic ulcer disease. 10.
Mycobacterial infection: Azithromycin or Clarithromycin are
recommended for the first line of prophylaxis and treatment of
pulmonary disease. E.g AIDS.
- Slide 98
- Side-effects Headache Dizziness Palpitation Heart burn Nausea
Anorexia Vomiting Rash Hearing loss
- Slide 99
- Drug-Drug Interactions Clarithromycin and erythromycin inhibit
CYP3A4. erythromycin potentiates the effects of Carbamazepine,
corticosteroids, digoxin, Theophylline, Warfarin.
- Slide 100
- Erythromycin Most frequently prescribed macrolide antibiotic.
It comes in several different salt and dosage forms that were
developed to circumvent some of the drawbacks it has chemically.
The absorption of oral erythromycin is enhanced if it is taken on
an empty stomach, but because of the high incidence of stomach
irritation, many of the agents are taken after meal or snack.
- Slide 101
- Continue Dosage range is: 1. children: 30-100mg/kg/day divided
dose 2. Adult: 500mg as single dose or Bid
- Slide 102
- Miscellaneous Drugs Vancomycin Clindamycin Metronidazole
Chloramphenicol
- Slide 103
- Vancomycin It is a natural bactericidal antibiotic structurally
unrelated to any other commercially available antibiotics. It is a
glycopeptide antibiotic discovered in 1956. It destroys bacteria by
binding to the bacterial cell wall producing immediate inhibition
of cell wall synthesis and death. It is the antibiotic of choice
for the treatment of MRSA.
- Slide 104
- Vancomycin
- Slide 105
- Continue The parenteral form is indicated for the treatment of
bone and joint infections and bacterial blood stream infections
caused by staphylococcus spp. Classified pregnancy category B.
Caution use: 1. Renal dysfunction 2. Hearing loss 3. Elderly
patients
- Slide 106
- Continue Contraindicated for hypersensitivity Available 125,
250mg capsules and 500mg, 1g for intravenous infusions. Adult
dosage is 0.5-2g per day in Tid for 7-10 days.
- Slide 107
- Mechanism of action Vancomycin inhibits the cell wall synthesis
by binding with high affinity, D-alanyl D-alanine. Vancomycin is a
bactericidal.
- Slide 108
- Toxicity Systemic toxicity of Vancomycin is high. It can cause
plasma concentration dependant nerve deafness which may be
permanent. Kidney damage is also dose related. Skin allergy and
fall of blood pressure during IV injection. Rapid IV injection has
caused chills, fever and intense flushing-Red man syndrome (an
adverse anaphlytical reaction to Vancomycin therapy causing
pruritis, flushing of the head and the upper part of the body, the
condition is caused by the release of histamine).
- Slide 109
- Uses MRSA Bacterial meningitis combination therapy with
Ceftriaxone or Cefotaxime. Used for dialysis patients Those
undergoing chemotherapy for cancer patients. Penicillin allergic
patients
- Slide 110
- Chloramphenicol Chloramphenicol was initially obtained from
streptomyces venezuelae in 1947. It was soon synthesized chemically
and the commercial product now is all synthetic. It has a
nitrobenzene substitution, which is probably responsible for the
antibacterial activity and it is intensely bitter taste.
- Slide 111
- Chloramphenicol
- Slide 112
- Mechanism of action Chloramphenicol inhibits bacterial protein
synthesis by interfering with transfer of the elongating peptide.
It specifically attaches 50S ribosome.
- Slide 113
- Pharmacokinetics Chloramphenicol is rapidly and completely
absorbed after oral ingestion. Chloramphenicol is primarily
conjugated with glucuronic acid in the liver and little is excreted
unchanged in urine. Plasma half life of chloramphenicol is 3-5
hours in adults. It is increased only marginally in renal
failure.
- Slide 114
- Therapeutic Uses Enteric fever- Typhoid Pyogenic meningitis:
Chloramphenicol 50-75mg/kg per day may be used after the third
generation of cephalosporin's. Anaerobic infections: Wound
infections, pelvic and brain infections. Intraocular infections:
Chloramphenicol is given systemically.
- Slide 115
- Adverse Effects Bone marrow depression Hypersensitivity
reactions like, fever, rashes, glossitis, Nausea Vomiting Diarrhea
Pain on injection Gray baby syndrome: the baby stop feeding,
vomited, hypothermic, abdomen distended, respiration become
irregular and gray cyanosis occur.
- Slide 116
- CHLORAMPHENICOL SIDE EFFECTS ID/CC: A 31 year old truck driver
visits a health clinic in Buroa Togdheer region, complaining of
recurrent infections, excessive bleeding, weakness and anemia. HPI:
He travels the border of Ethiopia daily and eats and sleeps there.
He has had a typhoid fever three times over the past five years,
for which he has been treated with high dose of chloramphenicol.
PE: Normal Labs: Anemia
- Slide 117
- Continue Treatment: Blood transfusions, cyclosporin for bone
marrow transplantation. Discussion: Chloramphenicol is a
bacteriostatic antibiotic that acts by inhibiting peptidyl
transferase in the 50s ribosomal unit. It is active against
anaerobes and riclettsiae as well as against typhoid fever and
meningococcal. In infants they produce gray baby syndrome. Owing to
its potentially fatal side-effect of Aplastic anemia,
chloramphenicol is used primarily for serious infections or acute
salmonella typhi infection.