tetracylines pharmacology

Question 1

what is the antibacterial spectrum for doxycycline and minocycline

Answer 1

1)Gram +ve cocci:

-Streptococci
-Staphylqcocci (even MRSA)
-Enterococci
-vancomycin resistant strains

2) Gram +ve bacilli like C.acnes and B.anthracis

3) Atypical bacteria
-Chlamydia
-Ureaplasma urealyticum
-Leigonella
-Rickettsia
-Mycoplasma pneumonia

4) Gram -ve

-Brucella
- V. cholera
-H.pylori
-H. influenzae
-H. duceryi
-K. pneumonia
-T.pallidum

Question 2

What bacteria are resistant towards doxycycline and minocycline

Answer 2

Proteus and pseudomonas are intrinsically resistant towards them

Question 3

what are the indications for doxycycline and minocycline

Answer 3

respirartoy infections ( pneumonia , anthrax , acute bronchitis)

STD (urethritis , syphilis , chancroid)

Skin infections (cellulitis , impetigo)

Cholera

acne

brucellosis

PEPTIC ULCER DISEASE

Question 4

Tigeycycline antibacterial spectrum

Answer 4

they have exact same spectrum as Doxy and Mino plus:

1) Gram +ve

-Listeria
-resistant S.epiermidis

2) Gram -ve

-anarobic B.fragilis

3) ESBL- producing

-E.coli
-Enterobacter
-Klesbsiella

Question 5

Indications of Tigeycycline

Answer 5

Acute bacterial skin and skin structure infections

Community acquired pneumonia

Intra-abdominal infection

Question 6

Mechanisms of resistance to tetracyclines

Answer 6

enzyme inactivation of tetracyclines

efflux of tetracycline

ribosomal protection by proteins

Question 7

Adverse effects of tetracyclines

Answer 7

GI effects - nausea , diarrhea , vomiting , candidiasis , enterocolitis

Hypersensitivity rxn ex rashes

Question 8

exception of tetracyclines

Answer 8

usually we avoid using them in pregnancy an children below 8 as it can cause discoloration of teeth and growth inhibition

exception is we can give them doxycycline if treatment course is less than 21 days less likelihood of chelation

Question 9

routes of administration for tetracyclines

Answer 9

DT - PO

MT - PO

TT - IV