Macrolides

MACROLIDES

Q. 1

A patient with discharge per vagina was evalu­ated and on endocervical biopsy Chlamydia was found. Treatment to be given in this case is :

 A

Azithromycin and contact tracing

 B

Mtronidazole only

 C

Doxycycline and metronidazole

 D

Azithromycin

Q. 1

A patient with discharge per vagina was evalu­ated and on endocervical biopsy Chlamydia was found. Treatment to be given in this case is :

 A

Azithromycin and contact tracing

 B

Mtronidazole only

 C

Doxycycline and metronidazole

 D

Azithromycin

Ans. A

Explanation:

Ans. is a i.e. Azithromycin and contact tracing

 Management :

  • Azithromycin + contact tracing is the treatment of choice.
  • In pregnancy drug of choice is erythromycin and second drug of choice is amoxicillin.

Partner should also be treated in chlamydial infection.


Q. 2

Erythromycin is given in decreased bowel motility because –

 A

It increases bacterial count

 B

It decreases bacterial count

 C

It binds to adenyl cyclase

 D

It binds to motilin receptor

Q. 2

Erythromycin is given in decreased bowel motility because –

 A

It increases bacterial count

 B

It decreases bacterial count

 C

It binds to adenyl cyclase

 D

It binds to motilin receptor

Ans. D

Explanation:

It Binds to motilin receptor [Ref KDT eVe p. 728;Goodman Gilman 1 Ith/e p. 988, 9891

“Motilin is a 22 aminoacid residue that is secreted by enterochromaffin cells and Mo cell in the stomach, small intestine and colon. Motilin acts on the G protein couple receptor present on the enteric neurons in the duodenum and colon and produces smooth muscle contraction in stomach and intestine”

  • Erythromycin is a potent stimulator of gastrointestinal motor activity.
  • It mimics nzotilin a peptide that stimulates motor activity.

– The main function of mutant is to increase the migrating myoeloectric complex component of gastrointestinal motility and stimulate the production of pepsin.

– Motilin is also the “house keeper of the gut” because it improves peristalsis in the small intestine and clears out the gut to prepare for the next meal.

A high level of motilin is secreted between the meals into the blood stimulating speed, contraction of the fundus and the antram and accelerated gastric emptying.

  • Erythromycin and related antibiotics act as non peptide motilin agonists and are sometimes used for their ability to stimulate G.I. motility.

–  Adminstration of low doses of erythromycin will induce peristalsis which provides additional support. – Motilin like effects erythromycin are most pronounced at higher doses (250-500 mg)

– Motilin mimicking property is shared to various extents by other macrolide antibiotics such as:- – Oleandomycin

– Azithromycin

– Clarithromycin


Q. 3

FK-506 is a

 A >It is a macrolide antibiotic
 B >Immunoglobulin antibody
 C >Non depolarising muscle relaxant
 D >Opioid analgesic
Q. 3

FK-506 is a

 A >It is a macrolide antibiotic
 B >Immunoglobulin antibody
 C >Non depolarising muscle relaxant
 D >Opioid analgesic
Ans. A

Explanation:

It is a macrolide antibiotic [Ref. K.D.T. 5th/e p 788]

  • FK-506 is commonly known as Tacrolimus.
  • Tacrolimus is a macrolide antibiotic produced by streptomyces tsukubaensis.
  • Tacrolimus acts as imnmunosuppressant by acting against calcineurin.
  • The other calcineurin inhibitor is cyclosporine.

Calcineurin inhibitors

  • Calcineurin inhibitors are perhaps the most effective immuno-suppressive drugs in routine use.

Role of calcineurin

  • Calcineurin acts as a intracellular signal transductor.
  • Once the T cell receptors are activated, signals are sent to the nucleus through the calcineurin, for the transcription of cytokine genes. This leads to production of IL-2 along with other interleukins.
  • Interleukin-2 and other cytokines leads to the proliferation of cellular and humoral immunity.
  • Calcineurin inhibitors, inhibitins the calcineurin.

Mechanism of action of cyclosporin

  • Cyclosporin enters the target cells and binds to a cytoplasmic protein called cyclophilin –> the complex then binds to and inactivates calcineurin — decreased production of IL-2 –)decreased immune response. Tacrolimus
  • The mechanism of action is almost similar to cyclosporine.
  • The slight difference is that it binds to different cycoplasnzic protein which is FKBP, but the subsequent steps are same i.e. inhibition of calcineurin —4 decreased production of IL-2 -1 decreased immune response. More on Tacrolimus
  • It is 10 times more potent than cyclosporine.
  • Because of more potent action it is also suitable for suppressing acute rejection that has set in.
  • It is particulary valuable in liver transplantation because its absorption is not dependent on bile.

It has the same toxicity profile as cyclosporine.

Quiz In Between


Q. 4

After taking certain medications a patient noticed yellowing of eyes. Which of the following most often causes cholestatic jaundice?

 A

INH

 B

Erythromycin estolate

 C

Pyrazinamide

 D

Ethionamide

Q. 4

After taking certain medications a patient noticed yellowing of eyes. Which of the following most often causes cholestatic jaundice?

 A

INH

 B

Erythromycin estolate

 C

Pyrazinamide

 D

Ethionamide

Ans. B

Explanation:

Cholestatic jaundice caused by erythromycin estolate (and rarely by the stearate) appears to be specifically related to the propionyl ester linkage of the 29 position. Thus, a history of cholestatic jaundice during therapy with oral erythromycin estolate is not an absolute contraindication to intravenous therapy with erythromycin gluceptate or lactobionate.
 
Ref: Aoki F.Y. (2005). Chapter 45. Principles of Antimicrobial Therapy and the Clinical Pharmacology of Antimicrobial Drugs. In Hall J.B., Schmidt G.A., Wood L.H.(Eds), Principles of Critical Care, 3e.

Q. 5

A patient with diabetic gastroparesis was given erythromycin because of the following property:

 A

It increases bacterial count

 B

It decreases bacterial count

 C

It binds to adenyl cyclase

 D

It imitates motilin

Q. 5

A patient with diabetic gastroparesis was given erythromycin because of the following property:

 A

It increases bacterial count

 B

It decreases bacterial count

 C

It binds to adenyl cyclase

 D

It imitates motilin

Ans. D

Explanation:

The effects of motilin can be mimicked by erythromycin. It induces phase III migrating motor complex activity and increases smooth muscle contractility.
It has multiple effects on upper GI motility, increasing lower esophageal pressure and stimulating gastric and small-bowel contractility.
It is a prokinetic agent is in patients with diabetic gastroparesis, where it can improve gastric emptying in the short term.
 
Ref: Sharkey K.A., Wallace J.L. (2011). Chapter 46. Treatment of Disorders of Bowel Motility and Water Flux; Anti-Emetics; Agents Used in Biliary and Pancreatic Disease. In L.L. Brunton, B.A. Chabner, B.C. Knollmann (Eds), Goodman & Gilman’s The Pharmacological Basis of Therapeutics, 12e.

 


Q. 6

Which of these following statements is wrong about Tacrolimus?

 A

It is one of the macrolide antibiotic

 B

It can be safely administered with any nephrotoxic drug

 C

Glucose intolerance is a well known side effect

 D

It is used as prophylaxis for transplant rejection

Q. 6

Which of these following statements is wrong about Tacrolimus?

 A

It is one of the macrolide antibiotic

 B

It can be safely administered with any nephrotoxic drug

 C

Glucose intolerance is a well known side effect

 D

It is used as prophylaxis for transplant rejection

Ans. B

Explanation:

The side effects of Tacrolimus includes, nephro and hepato toxicity.

It can also cause hypertension, tremors, seizure, diabetes mellitus and blurred vision.

It should be better avoided with other hepato and renal toxicity drugs.

Ref: Manzoor M. Khan (2008), Chapter 4 “Immunesupressive Agents”, In the book, “Immunopharmacology”, Springer Publications, USA, Page 91 ; Katzung, 9th Edition, Pages 941, 942

Quiz In Between


Q. 7

Patient is on Cisapride for gastroesophageal reflux develops upper respiratory tract infection, and physician prescribes erythromycin. What pharma­logical interaction would be expected –

 A

Dereased level of erythromycin and exacerbation of URTI

 B

Decreased effect of cisapride due to enzyme inductor of erythromycin

 C

Fatal ventricular arrhythmia

 D

Hemorrhagic cystitis

Q. 7

Patient is on Cisapride for gastroesophageal reflux develops upper respiratory tract infection, and physician prescribes erythromycin. What pharma­logical interaction would be expected –

 A

Dereased level of erythromycin and exacerbation of URTI

 B

Decreased effect of cisapride due to enzyme inductor of erythromycin

 C

Fatal ventricular arrhythmia

 D

Hemorrhagic cystitis

Ans. C

Explanation:

Ans. is ‘c’ i.e., Fatal ventricular arrythmia


Q. 8

Fk-506 is a –

 A

It is a macrolide antibiotic

 B

Immunoglobulin antibody

 C

Non depolarising muscle relaxant

 D

Opioid analgesic

Q. 8

Fk-506 is a –

 A

It is a macrolide antibiotic

 B

Immunoglobulin antibody

 C

Non depolarising muscle relaxant

 D

Opioid analgesic

Ans. A

Explanation:

Ans. is ‘a’ i.e., It is a macrolide antibiotic

o Fk-506 is commonly known as Tacrolimus.

o Tacrolimus is a macrolide antibiotic produced by streptomyces tsukubaensis.


Q. 9

Which of the following statements is true regarding pertussis ?

 A

Neurological complication rate of DPT is I in 50000

 B

Vaccine efficacy is more than 95%

 C

Erythromycin prevents spread of disease between children

 D

The degree of polymorphonuclear Leukocytosis correlates with the severity of cough

Q. 9

Which of the following statements is true regarding pertussis ?

 A

Neurological complication rate of DPT is I in 50000

 B

Vaccine efficacy is more than 95%

 C

Erythromycin prevents spread of disease between children

 D

The degree of polymorphonuclear Leukocytosis correlates with the severity of cough

Ans. C

Explanation:

Ans. is ‘c’ i.e., Erythromycin prevents spread of disease between children

o Efficacy of Pertusis Vaccine – reported to be from 70-90%

o Risk of acute encephalopathy – is 1 in 40, 000 cases following DTP vaccine.

o Pertusis toxin produces Lymphocytosis & not polymorphonuclear Leukoctyosis.

Leukocytosis due to absolute lymphocytosis is characteristic in late catarrhal or paraoxysmal stage.

o Prophylactic erythromycin prevents infecting bacteria to become established – prevents spread of disease – Park

Quiz In Between


Q. 10

24 years old male complains of mild urethral mucoid discharge after sexual contact with a sex-worker. Examination is normal. Drug used to treat such a patient:         

September 2012

 A

Azithromycin 1 mg single dose

 B

Azithromycin 1 mg for 3 weeks

 C

Azithromycin 500 mg single dose

 D

Azithromycin 1 gram single dose

Q. 10

24 years old male complains of mild urethral mucoid discharge after sexual contact with a sex-worker. Examination is normal. Drug used to treat such a patient:         

September 2012

 A

Azithromycin 1 mg single dose

 B

Azithromycin 1 mg for 3 weeks

 C

Azithromycin 500 mg single dose

 D

Azithromycin 1 gram single dose

Ans. D

Explanation:

Ans. D i.e. Azithromycin 1 gram single dose

The clinical presentation corresponds to a diagnosis of NGLI/ non gonococcal urethritis


Q. 11

Treatment of graunolma inguinale is ‑

 A

Tetracycline

 B

Azithromycin

 C

Clarithromycin

 D

Streptomycin

Q. 11

Treatment of graunolma inguinale is ‑

 A

Tetracycline

 B

Azithromycin

 C

Clarithromycin

 D

Streptomycin

Ans. B

Explanation:

Ans. is ‘b’ i.e., Azithromycin

Granuloma inguinale or Granuloma venerum or Donovanosis

  • Caused by Calymmatobecteriunt granulomatis, a gram negative intracellular bacteria.
  • IP is 1- 4 weeks.
  • Begins as one or more subcutaneous nodules that erode through skin to produce ulcer. Ulcer has following characterstics.
  1. Painless
  2. Bleeding withred granulation tissue
  3. Indurated
  • Subcutaneous granulomas of inguinal region in Donovenosis look like enlarged lymph nodes but these are not enlarged lymph nodes. Therefore, these are known as Pseudobubos. Sites of the lesions are genitalia (90%), inguinal (10%), and anal regions.

Complications are pseudoelephentiasis, phimosis, paraphymosis.

Diagnosis

  • Preferred method is demonstration of typical intracellular Donavan Bodies within large mononuclear cells visualised in smear prepared from lesion or biopsy specimen. It shows safety pin appearance.

Treatment

  • Azithromycin is the DOC. Alternatives are doxycycline (2nd choice) and chloremphenicol.
  •  Streptomycin, once used, is not used now.

Quiz In Between



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