Description of Penicillin and Cephalosporins

Session 4: Description of Penicillin and Cephalosporins

Total Session Time: 120 minutes

Prerequisites

Learning Tasks

By the end of this session students are expected to be able to:

Resources Needed:

SESSION OVERVIEW

Activity/

Step Time Content

Method

1 05 minutes Presentation Introduction, Learning tasks

Presentation/

2 20 minutes Indications of Penicillins and Cephalosporins

Buzzing

Presentation/ Contraindications of Penicillins and

3 20 minutes

Brainstorming Cephalosporins

Dose, Dosage and Course of Penicillins and

4 30 minutes Presentation

Cephalosporins

Presentation/ Listing side effects and adverse effects of

5 20 minutes

Brainstorming Penicillins and Cephalosporins Drugs

Description of interactions and precautions of

6 15 minutes Presentation

Penicillins and Cephalosporin Drugs

7 05 minutes Presentation Key Points

8 05 minutes Presentation Evaluation

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SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning tasks (5 minutes)

READ or ASK students to read the learning tasks and clarify

ASK students if they have any questions before continuing.

STEP 2: Indications of Penicillins and Cephalosporins (20 minutes)

Activity: Buzzing (5 minutes)

ASK students to pair up and buzz on the following questions for 2 minutes

ALLOW few pairs to respond and let other pairs to add on points not mentioned

WRITE their response on the flip chart/board

CLARIFY and SUMMARIZE by using the content below

The remarkably powerful and specific activity of antimicrobial drugs is due to their

selectivity for targets that are either unique to microorganisms or much more important in

them than in humans

o Have greatest activity against gram-positive organisms, gram-negative cocci, and

non-lactamase-producing anaerobes.

o However, they have little activity against gram-negative rods,

o They are active against staphylococci and streptococci but not against enterococci,

anaerobic bacteria, and gram-negative cocci and rods.

o Extended-spectrum penicillins (ampicillin and the antipseudomonal penicillins)

retain the antibacterial spectrum of penicillin and have improved activity against

gram-negative organisms

o Commonly used Penicillins include:

 Amoxicillin

 Flucloxacillin

 Benzyl penicillin

 Procaine penicillin

 Ampicillin

PST 04211 Basic Pharmacology NTA Level 4 Semester 2 Facilitator Guide

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o similar to penicillins

o But more stable to many bacterial lactamases

o Therefore have a broader spectrum of activity

o However, strains of E coli and Klebsiella species expressing extended-spectrum

lactamases that can hydrolyze most cephalosporins are becoming a problem

o Cephalosporins are not active against enterococci and L monocytogenes

o Commonly used Cephalosporins include:

 Cefuroxime

 Cefotaxime

 Ceftriaxone

 Cefalexin

 Cefradoxil

STEP 3: Contraindications of Penicillins and Cephalosporins (20 minutes)

Activity: Brainstorming (5 minutes)

Ask students to brainstorm on the following question:

What are contraindications of penicillins and cephalosporins?

ALLOW few students to respond

WRITE their responses on the flip chart/ board

CLARIFY and SUMMARISE by using the content below

o In patients with renal failure

o In patients with penicillin hypersensitivity

o In patients with cephalosporin hypersensitivity

o In patients with a history of anaphylaxis to penicillins

STEP 4: Dose, Dosage and Course of Penicillins and Cephalosporins (30

minutes)

o Amoxicillin 250-500mg every 6hourly for 5-7 days

o Ampicillin 250-500mg every 6hourly for 5-7 days

o Penicillin G up to 2.4mU/dose I.M

o Orally

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o Parenterally

 can also be administered intramuscularly

STEP 4: Side Effects and Adverse Effects of Penicillins and Cephalosporins

(20 minutes)

Activity: Brainstorming (5 minutes)

Ask students to brainstorm on the following question:

ALLOW few students to respond

WRITE their responses on the flip chart/ board

CLARIFY and SUMMARISE by using the content below

o Adverse effects and side effects:

 The penicillins are remarkably nontoxic

 Most of the serious adverse effects are due to hypersensitivity.

 All penicillins are cross-sensitizing and cross-reacting

 Allergic reactions include anaphylactic shock (serum sickness-type reactions,

urticaria, fever, joint swelling, angioneurotic edema, intense pruritus, and

respiratory embarrassment variety of skin rashes

 Oral lesions, fever, interstitial nephritis vasculitis may also occur

 Most patients allergic to penicillins can be treated with alternative drugs

o Adverse effects and side effects:

 Cephalosporins are sensitizing and may elicit a variety of hypersensitivity

reactions that are identical to those of penicillins

 These include anaphylaxis, fever, skin rashes, nephritis, granulocytopenia, and

hemolytic anemia

 Local irritation can produce severe pain after intramuscular injection and

thrombophlebitis after intravenous injection

 Renal toxicity, including interstitial nephritis and even tubular necrosis.

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STEP 5: Interactions and Precautions of Penicillins and Cephalosporins

(15 minutes)

o Interactions

 Reduce excretion of cytotoxic like methotrexate

 Allopurinol increases risk of rash when used with amoxicillin or ampicillin

 Effects of anticoagulants are altered by penicillin

o Precautions

 History of allergy

 Most patients allergic to penicillins can be treated with alternative drugs.

o Interaction and precaution

 Drugs with the methylthiotetrazole ring can also cause severe disulfiram-like

reactions: consequently, alcohol and alcohol-containing medications must be

avoided

Step 7: Key Points (5 minutes)

o gram-positive organisms

o gram-negative cocci

o non- beta-lactamase-producing anaerobes

o But more stable to many bacterial lactamases

o Therefore have a broader spectrum of activity

reactions

STEP 8: Evaluation (5 minutes)

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References

MoHSW (2013). Standard Treatment Guidelines & National Essential Medicines List

Tanzania Mainland (4th ed.). Dar es salaam: Tanzania Government Printers.

Sally, S.R. Jeanne, C.S. (2000). Introductory Clinical Pharmacology (6thed) New York,

Lippincott Williams and Wilkins.

School of Pharmaceutical Sciences (2011).Tanzania Pharmaceutical Handbook (2nd ed.). Dar

es Salaam: ARDHI University Press.

Pharmacotherapy: a pathophysiologic approach (9th ed.). New York: McGraw-Hill

Education.

The Royal Pharmaceutical Society of Great Britain (2007). Martindale, the Extra

Pharmacopoeia (5th ed). London: Pharmaceutical Press.

The Royal Pharmaceutical Society of Great Britain (2009). British National Formulary (59th

ed). London: BMJ Group and RPS Publishing.

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