Side Effects and Toxicity

Question 1

Outline immediate hypersensitivity.

Answer 1

• Anaphylactic Shock (v. life threatening)
• Within minutes of antibiotic admission.
• IgE mediated
• Itching, uticaria (hives), nausea, vomiting, wheezing, shock, laryngeal oedema.

Question 2

Outline delayed hypersensitivity.

Answer 2

• Can take hours to days to develop.
• Drug rashes are the most common
• Drug fever, serum sickness and erythema nodosum (inflammation of fat cells under skin) can occur too.
• Can be fatal (Stevens-Johnson syndrome)

Question 3

Outline some of the GI side effects of antibiotic use.

What effect does C. diff have?
How is C. diff identified as the problem?

Answer 3

• Nausea and Vomiting common
• Diarrhoea associated with toxin production of C. diff (can overgrow normal flora during antibiotic therapy)
• C. diff overgrowth can result in mild symptoms (diarrhoea) to life threatening (pseudomembranous collitus - inflammation in colon) - toxin identification is used in detection (becasue c. diff is normal flora)

Question 4

How is C. diff treated?

Answer 4

Oral metronidazole or oral vancomycin

Antibiotic that may have caused the infection should be stopped.

Patient is also kept in isolation.
+ hand hygeine vital (not killed by alcohol rub)

Question 5

What is the main cause of the increase in C. diff infections?

Answer 5

Over use of broad spectrum antibiotics.

Question 6

How is the government attempting to reduce the high number of C. diff infections?

Answer 6

Use of narrow spectrum antibiotics. And the attempt to reduce the use of the “4 C’s” - cephalospoins, ciprofloxacin, co-amoxiclav, clindamycin.

Question 7

Outline how thrush can be a side effect of the use of antibiotics.

Answer 7

• Broad spectrum antibiotics suppress normal flora
• Can reslut in an overgrowth of resistant organisms.

E.g. use of broad spectrum penicillins or cephalosporins can be complicated by the candida albican fungi, resulting in thrush

Question 8

Outline how liver toxicity can occur as a side effect to antibiotic use.

What drugs have been associated with liver toxicity?

Answer 8

variety of side effects, from the transient elevation if enzymes to hepatitis
- More common in patients that have a ore-existing liver condition OR in pregnancy.

Tetracycline
Isoniazid (INH)
Rifampicin
Flucloxacilin

Question 9

Outline how renal toxicity can occur as a side effect of antibiotic treatment.

When is kidney toxicity most commonly seen?

Answer 9

• Kidney is important route of drug excretion
• Nephrotoxicity
• More common in patients with a pre existing condition.
• Usually reversible but can sometimes be permanent.

With aminoglycoside group of antibiotics or vancomycin.

Question 10

What antibiotics are included in the aminoglycoside group?

Answer 10

Gentamicin, netilmicin, amikacin

Question 11

With what drugs is ototoxicity seen ?

Answer 11

Often seen following aminoglycoside or vancomycin use.

Question 12

With what drug is optic neuropathy seen?

What needs to be monitored when on this drug?

Answer 12

Ethambutol (anti tuberculosis drug)

Optic nerve function, because optic nerve damage can occur.

Question 13

What drugs can cause encephalopathy and convulsions?

When does it especially occur?

Answer 13

• High dose penicillin
• Cephalosporin
• Aciclovir (anti-viral)

If the does is not reduced in the presence of renal impairment.

Question 14

Which drugs can cause peripheral neuropathy?

Answer 14

Metronidazole
Nitofurantoin
Isoniazid

Question 15

What is peripheral neuropathy?

Answer 15

• Damage to or disease affecting nerves, which may impair sensation, movement, gland or organ function, or other aspects of health, depending on the type of nerve affected.

Question 16

Outline how haematological toxicity can occur as a side effect of antibiotic treatment?

Answer 16

• Antimicrobials can have a toxic effect on bone marrow (depression of some cell production)

Question 17

What drugs can cause haematological toxicity?

Answer 17

Co-trimoxazole - acts as a competitive inhibitor of folic acid synthesis. Resulting folate deficiency can lead to megaloblastic anaemia.

Question 18

What is:

1. ) neutropenia
2. ) pancytopenia
3. ) megaloblastic anaemia

Answer 18

1. ) Abnormally low concentration of neutrophils in the blood.
2. ) deficiency of all three cellular components of the blood (red cells, white cells, and platelets).
3. ) a condition in which the bone marrow produces unusually large, structurally abnormal, immature red blood cells (megaloblasts)

Question 19

How do you prevent adverse reactions?

Answer 19

• Antimicrobials only used when indicated.
• Minimum dose and duration necessary to achieve efficacy.
• Care exercised when administering antimicrobials to vulnerable groups (extremes of age, pregnancy, liver/kidney problems) .
• Drugs with low therapy range should be closely monitored.