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Pharmacology 2 > 5. Tetracyclines, macrolides, lincosamines > Flashcards

5. Tetracyclines, macrolides, lincosamines Flashcards

1
Q

Inhibitors of protein synhtesis

A
  • Aminoglycosides
  • tetracyclines
  • macrolides
  • lincosamides
  • pleuromutilins
  • phenicols
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2
Q

Classification of tetracyclines

A

Naturally occuring tetracyclines:

  • Streptomyces spp.
  • oxytetracycline
  • chlortetracycline

Semisynthetically derived tetracyclines:

  • deoxycycline, minocycline

Short acting:

  • tetracycline
  • oxytetracycline
  • chlortetracycline

Intermediate-acting:

  • demeclocycline

Long acting:

  • doxyxycline, minocycline
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3
Q

Classification of tetracyclines

  • structure, properties
A
  • Lipophilic, pharmacokinetic: excellent
  • penetrate BBB, penetrate intra-cellularly
  • Will cause yellowish discolouration of the teeths in growin animals
  • especially the Short acting
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4
Q

Tetracyclines

  • mechanism of action, mode of action
A

Mechanism of action:

  • safe drugs
  • inhibition of protein synthesis (30S subunit)
  • At high concentrations (-cidal effect) loss of cuntional integrity of cytoplasmic membrane
  • concentrated in the urine. in the urine they become bactericical. High conc = destroy the cell membrane

Mode of action:

  • Generally Bacteristatic (but urine!)
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5
Q

Tetracyclines

  • antimicrobial spectrum
A

all tetracyclines are similar

  • Bacteria
  • both aerobic and aneaerobic
  • gram + and gram -
  • Broad spectrum = resistance
  • Very sensitive: Mycoplasma, Rickettsiae, Chlamydophilae, Wolbachia spp.
  • Borrelia: 1st choice Doxicyclin
  • Anaplasma: 1st choice doxicyclin
  • Bordetella: 2st choice doxicyclin
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6
Q

Tetracyclines

  • chlamydophilae
A
  • tetracyclines are 1st choice
  • cats + Ru
  • zoonotic respiratory infection
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7
Q

Tetracyclines

  • mycoplasma haemofelis
A
  • Surface of erythrocytes of cats –> anemia + icterus
  • tetracyclines (doxiyclin?) 1st choice
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8
Q

Tetracyclines

  • anaplasma phagocytophilum
A
  • lives in the WBC
  • mainly in dogs –> fever, lameness
  • 1st coice: doxicyclin
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9
Q

Tetracyclines

  • Wolbachia spp.
A
  • unique bacteria
  • bacterium of Diophilaria (heaertworm of dogs)
  • 1st choice doxycillin
  • If you destroy the heartworm this will lead to relase of Wolbachia, which will kill the animal
  • therefore always treat wolbachia first with doxicillin, and then kill the heartworm
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10
Q

Tetracyclines

  • protozoa
A
  • work moderate in these cases
  • Plasmodium spp., Entamoeba histolytica (not so common), Babesia spp., Theileria spp.
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11
Q

Tetracyclines

  • mechanism of resistance
A

- Impared uptake into bacteria

  • the bacteria dont let the AB penetrate the wall

- Active efflux

  • Decomposition
  • destroy the AB
  • Altering of binding site
  • the 30S binding site
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12
Q

Tetracyclines

  • resistance
A
  • frequently resistant
  • Ab ovo
  • Pesuedomonas aeruginaosa: not sensitive to tetracyclines

Acquired resistance: because of the widepread use

  • pathogenic E-coli
  • salmonella spp.
  • Pasteuralle multocida, mannheimia haemoltytica (30-40% resistance, so can work)
  • Staph. aureus, streptococci: 50% resistance,
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13
Q

Tetracyclines

  • pharmacokinetic features
A
  • Classic TTC
  • less lipophiliv, short acting
  • Oxy-chlorotetracyclines: 15% abosorbed in pigs, 80% eliminated
  • excretion: 50% active and inactive, therefore not used for UTI
  • Long acting TTC:
  • more lipophilic
  • Excretion in dog (morsly inactive): 20% in urine, 5% in bile, 75% in large intestine –> can be given to anmals with kidney and liver failure
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14
Q

Tetracyclines

  • indications
A

General infections:

  • bronchopneumonia
  • reisitance not more than 20%. 1st choice is tetracyclines
  • Foot diseases
  • sheep+ cattle
  • TTC have moderate activity
  • UTI: not used! we have better drugs
  • Metritis, mastitis

Specific conditions: - only treated with TTC

  • lyme disease and ehrlichiosis (especially doxyxycline)
  • 10mg/kg TID, duration 6-8 weeks
  • chlamydophilosis
  • feline mycoplasmosis (formerly haemobartonellosis)
  • infectious keratoconjunctivitis in cattle (moraxella bovis): injectable TTC
  • proliferative enteropathy in horses (lawsonia intracellularis)
  • Doxycycline only drug that can be used in horse, lethal if not treated!
  • nocardiosis
  • heartwater
  • anaplasmosis
  • heartworm (dirofilarosis)
  • Doxycycline 10mg/kg BID for 30 days
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15
Q

Tetracyclines

  • side effects and toxicity
A
  • oral application (Fe!):
  • Tissue irritant –> irritation of esophagus.
  • GI disturbances
  • Dysbacteriosis
  • Rapid IV injection: collapse
  • Because TTC bind to calcium in blood and cause hypocalcemia –> increase contractility of the heart
  • Tissue necrosis: IV or simultaniously
  • yellow discoloration of teeth
  • hepatotoxiciy
  • infrequent, 1-2% but in that case it can be severe!
  • eg in case of Lyme disease you give hepatoprotective aswell
  • nephrotoxicity: mild, not severe
  • photosensitivity:
  • very sensitive to direct sunlight, 50SPF topical application is needed
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16
Q

Phenicols

  • source and chemistry
A
  • produced by: Streptomyces venezuelae
  • lipophilic, small molecules
  • elimination in bile is excellent
  • Chloramphenicol, tiamphenicol, florfenicol
  • Chlorampenicol: see structure in ppt.
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17
Q

Phenicols

  • mechanism of action and mode of action
A
  • inhibition of protein synthesis (50S)
  • not to be combined with other 50S inhibitors
  • bacteristatic
18
Q

Phenicols

  • mechanism of resistance
A
  • Acetyl transferases
  • most important.
  • enzymes that will put an acetyl group on the AB

- impared utake into bacteria

- active efflux

19
Q

Phenicols

  • antimicrobial spectrum
A
  • very borad
  • gram + and gram -
  • anaerobic and aerobic
  • resistant against P. aeruginosa
  • very sensitive: mycoplasma, chlamidophila, rickettsia
  • Aeromonas salmonicida, Vibrio anguillarum (florfenicol: only AB for fish!)
20
Q

Phenicols

  • pharmacokinetics
A
  • Absorption:
  • Excellent (80-100%) –> Oral almost the same as IM and SC
  • Eye: 5% absorption –> therefore it can have all the side effects, but not frequent!
  • Distribution:
  • Excellent (bones, placenta, prostate)
  • Special barriers
  • Intracellular
  • Metabolism and excretion:
  • extensive in the liver (liver disease!)
  • urine (mainly inactive, can not be used for UTI) + bile elimination
  • Half life:
  • Ruminants (longer, every 2nd day) > swine (Shorter. Every day) > cat (Shorter. BID) > dog (Shortest. SID)
  • –> therefore not used in cats and dogs
21
Q

Phenicols

  • Side effects
A
  • Anemia
  • Dose dependent (7-10 days, liver) –> all the phenicols. because of the protein synthesis inhibition
  • Dose independent –> only chloramphenicol. Lethal - one molecule can cause it
    • Ho 50000:1 –> low chance, but severe consequences.
    • Excellent absorption (skin, eyes) NB always use gloves
    • Prohibited in food producers
    • Long term use also effects WBC
  • Immunosuppression
  • Do not give during vaccination program
  • Pain at injection site
22
Q

Phenicols

  • indications
A

Primary food producing animals (florfenicol)

  • Respiratory diseade (BRD, SRD)
    • Mycoplasma + fastidious organisms
  • Foot diseases
  • infectious keratoconjunctivitis
  • Fish Aeromonas infection

Small animals

  • (Short half-life, needs many doses: not convenient, very infrequent use)
  • Eye infections
  • prostatitis
  • meningitis
  • MRSP, MRSA infections
23
Q

Macrolides

  • source and chemistry
A
  • streptomyces soil-borne bacteria
  • macrolytic lactone ring (lipophilicity) attached to sugar moieties
  • weak bases

Summary:

  • high intracellular concentrations
  • broad distribution in tissues
  • especially in resp. tract –> used against resp. infections (mycoplasma, mannheimia etc)
  • prolonged half-lives
  • stays in tissues, organs and eliminated by the blood very slowly
24
Q

Macrolides

  • mechanism of action, mode of action and resistance
A
  • inhibition of protein synthesis (50S)
  • Bacteristatic
  • in higher conc –> bacteriocidal (primarily in the lungs - resp. infections)

Resistance:

  • decreased permability
  • degrading enzymes
  • modified binding site (50S) –> cross resistance (Lincosamides, phenicols)
  • The modified binding side (50S) will not bind the macrolides –> causing cross resistance to other bacterial classes –> multidrug resistance!
25
Q

Macrolides

  • most important macrolides
A

Veterinary - newer

  • Tulathromycin - semisynthetic - trilamilide
  • gamithromycin - semisynthetic - azalide (has two N-groups –> increased ion trapping –> long duration of action)

Human medicine, companion animals

  • azithromycin - semisynthetic - azalide
26
Q

Macrolides

  • antimicrobial spectrum
A

Gram positive

Few Gram negative (anaerobic!)

  • Fastidious bacteria (Pasteurella, mannheimia etc)
  • Capylobacter spp.: Azithro, clarithro, erythro
  • enteritis in dogs, cats, humans. from raw chicken meat
  • Brachyspira hyodysenteriae: Tylosin (always resistant, out of date now), Tylvalosin (excellent choice)
  • Lawsiona intracellularis: Tylosin (swine), Tylvalosin (swine), Toxicyclin (horse)
  • proliferative enteropathy - swine, horse
  • 1st choice: macrolides
  • Bordetella spp.
  • Kennel cough in dog, atrophic rhinitis in igs
  • Mycoplasma, Chlamydia spp.
  • Borrelia spp.
  • 2nd choice: macrolides. (1st choice: deoxycycline9
  • Rhodococcus equi: Azithro, clarithro, erythro
  • fatal pneumonia
27
Q

Macrolides

  • Pharmacokinetics
A

- Absorption:

oral absorption: variable

Exceptions:

  • Erythromycin: acid sensitive. Capsules to prevent breakdown. Esters (synthesised and gets resistant to the gastric juice) –> good for poultry, pigs
  • Tylosin phosphate: low absorption =15%. Good in intesintal infections
  • Tartarate: 30% absorption. Good in resp. infections

Im, SC absorption is good (very irritant!)

  • Never IV! not water soluble
  • Painfull, therefore never given to small animals by injection, only PO!
  • Large animals can tolerate injection

- Distribution:

  • Good (bones, placenta, prostate) –> but can not penetrate BBB
  • Respiratory tract –>Lung conc. can be 100times higher than in the blood
  • Intracellular

- Metabolism:

  • extensive in the liver –> contraindicated in liver disease
  • 90% of the drug is excreted with bile: In both active and inacive form = can give serious bacteriosis, therefore very toxic in horse, rabbits and herbivore rodents, BUT not in foal!
  • CYP450 enzyme inhibitor –> interactions (toxicity increase!)
    • Ionophor antibiotids (coccidiosis)
28
Q

Macrolides

  • Side effects
A
  • GI irritation –> vomitting, diarrhea (also motilin agonists, especially erythromycin –> enhance gastric emptying)
  • Dysbacteriosis
  • fatal enterocolitis in adult horses
  • but foals (R. equi) tolerates the medication
  • Tissue irritation!
29
Q

Macrolides

  • Erythromycin
A

Similar spectrum as Penicillins –> in humans it is used for Penicillin allergic patients

Rare usage:

  • Small animals: capylobacteriosis
  • Food producing animals:
  • resp. tract infection (incl. mycoplasmosis)
  • diamond skin disease etc.
  • Horses: more frequently used
  • R. equi (+rifampicin): drug against TB in humans. 6 weeks duration of treatment, every day orally = expensive
30
Q

Macrolides

  • Spiramycin
A
  • higher tissue levels
  • frequent use in oral cavity infections (small animals): stomatitis
  • Large animals: infrequent (mastitis)
31
Q

Macrolides

  • Tylosin
A

Frequent resistance - in swine dysentery 95%!

  • Pigs:
  • Never used against swine dysentery (was used before)
  • usefull: Lawsiona intracellularis (proliferative enterophathy)
  • Pigs, ruminants, poultry:
  • respiratory tract infections, necrotic enteritis (clostridium) very sensitive to Tylosin
  • Small animals:
  • ARD = Antibiotic Responsive Diarrhea: affects large dogs, causes chronic diarrhea. Idiopathic
32
Q

Macrolides

  • Tilmicosin
A

Ruminants + pigs, poultry (ØGOAT!) only! highly toxic in other species!

  • Most toxic macrolide (cardiotoxic - lethal) –> horses, goats, humans!
  • Cattle SC (Only! can dive from IV)
  • Pigs + poultry PO
  • excellent levels in the lungs (60:1 to plasma) –> 3 days!
  • Fastidious bacteria + mycoplasma very sensitive!
33
Q

Macrolides

  • Tylvalosin
A
  • Oral application, new drug
  • pigs, poultry
  • outstanding against:
  • B. hyodysenteriae
  • L. intracellularis
  • Mycoplasma + fastidoius bacteria (not so much)
34
Q

Macrolides

  • Tulathromycin, gamithromycin
A
  • injectable application, new drugs (ruminants, pigs)
  • Triamilide and Azilide antibiotics –> excellent distribution
  • outstanding against:
  • fastidious organisms + mycoplasma
  • Gram + coverage decreases
  • several 100x higher concentation in the lungs –> respiratory tract infections!
  • ONLY injectable! can not be given in drinking water
35
Q

Macrolides

  • Tildipirosin
A
  • The longest acting: 1 month
  • No activity against Mycoplasma
  • Injectable application, new drugs (ruminants, pigs)
  • excellent distribution
  • Outstanding against:
  • Fastidious organisms + NO mycoplasma
  • several 100x higher conc. in the lungs –> respiratory tract infections!
36
Q

Macrolides

  • Azithromycin, clarithromycin
A
  • Azalite: long action and better distribution
  • clarithro: normal macrolide
  • Oral application, ew drugs (small animals, humans)
  • excellent absorption and distribution (half life is long)
  • outstanding against:
  • Gram + (1st choice is penicillin…)
  • Fastidious Gram negatives
  • Borrelia (small animals), Mycoplasmae (small animals), Capyloacter (small animals), R. equi (horse)
  • good lung concentrations (Azithro <-> clarithro)
  • Indications:
  • Side effects: vomitting (always give together with food)
37
Q

Lincosamides

  • mechanism of action, mode of action, resistance, phamacokinetics
A
  • Inhibition of protein synthesis (50S)
  • Never combine them with other 50S! they are antagonists
  • Bacteristatic
  • cross resistance with macrolides and phenicols
  • similar pharmacokinetics
  • good absorption
  • excellent distribution (bones, IC etc, but not BBB)
  • these drugs are 1st choice in osteomyelitis (primary bact strept. aureus), eg after bone surgery
  • metabolism in the liver
  • excreted via bile and urine: not sensitive for UTI, and causes dysbacteriosis
  • These are the most toxic AB in the intestinal flora –> prohibited in Eq, rabbit, herbivore rodents!
38
Q

Lincosamides

  • toxicity, spectrum
A

Toxicity:

  • very severe tissue irritation
  • dysbacteriosis (life threatening entercolitis)

Spectrum:

  • gram + and anaerobic!!
  • but not for fastidious
  • B. hyodysenteria, L. intracellulars
  • Mycoplasma
  • Campylobacter
39
Q

Lincosamides

  • Lincomycin
A

Lincomycin + spectinomycin = frequent synergism = Lincospectin (excellent choice for resp. inf.)

  • mainly in food producing animals

Indications:

  • foot rot, wounds, mastitis, metritis (gram +)
  • swine dysentery, proliferative enteropathy
  • mycoplasmosis (synergy)
40
Q

Lincosamides

  • clindamycin
A
  • often used by dentists
  • more active, mainly in companion animals
  • dermatitis, abscesses, oral cavity
  • anal sacculitis
  • osteoyelitis
  • orally
  • side effects: vomitting and dysbacteriosis (give probiotics!)
41
Q

Pleuromutilins

  • mechanism of action, mode of action, resistance, pharmacokinetics
A
  • very similar compounds as the others
  • only large food producing animals!
  • Tiamulin, valnemulin: much safer than Lincosamine, never cause dysbacteriosis!
  • inhibition of protein syntehsis (50S)
  • bacteriostatic
  • cross resistance with macrolides and phenicols

- similar pharmacokinetics:

  • good absrotpion
  • excellent distribution
  • metabolism in the liver: enzyme inhibitors (therefore icreased metabolism of other drugs which will increase toxicity) –> interactions, inophore anticoccidials
  • excreted via bile and urine
42
Q

Pleuromutilins

  • toxicity, spectrum, indications
A

Low toxicity, very safe drug!

  • skin erythema, vulvar edema
  • caused by inactive metabolites excreted by the urine

Similar spectrum to macrolides

  • gram +
  • fastidious
  • B. hyodysenteriae, L. intracellularis, Mycoplasmae

Indications:

  • Swine dysentery, Proliferative enteropathy, Mycoplasmosis + respiratory (pigs, poultry)

Drugs:

  • Tiamulin: orally + inj.
  • Valnemulin: orally

Pharmacology 2 (13 decks)

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