About pharmacology

1. CHAPTER # 02
Drugs Used To Treat And
Prevent Infections

2. Pharmacology Presentation
Members
• Almer Saleem
• Shakaina Abid
• Saul Suleman
• Elisha Dewan
• Uzma Shahid
• Arslan Munir
• Triza Tariq

3.  Define the most commonly used drug category that is
used to prevent and treat infections Including antiphrastic
 Briefly discuss action and effects of selected drug
category
 List some of the most commonly used drugs for each
drugs category
 Discuss the nursing measures/patient education which
can be taken if patient is using to treat and prevent
infection

4. Parasite
• Any living thing that lives in (endoparasite) or on
(ectoparasite) another living organism is called a
parasite.
• It obtains food and/ or shelter from the host and
contributes nothing to its welfare.
• Some parasites cause irritation and interference with
bodily functions, others destroy host tissues and release
toxins into the body, thus injuring health and causing
disease.

5. Antiparasitics, drugs which kill or inhibit the growth of parasitic
organisms,may be subdivided into the following therapeutic
categories:
• Antinematodal
• Anticestodal
• Antilung worm
• Antitrematodal
• Antifilarial
• Antiprotozoal
• Insecticide

6. Antiparasitics are a class of medications which are indicated for the
treatment of parasitic diseases.
Such as those caused by
• Helminths
• Amoeba
• Ectoparasites
• Parasitic Fungi
• Protozoa among others.

7. Protozoal infections
Trypanosomiasis
Toxoplasmosis
Amebiasis
Protozoa
Schistosomiasis
Malaria

8. Helminth infections
 Nematode
 Cestode
 Trematode
Nematode
Nematode Cestode

9. Ectoparasitic infections
 Scabies
 Pediculosis

10. Amebiasis
 Disesase of large intestine caused by Entamoeba histolytica
 Organism- 2 forms
1. Motile trophozoite form
2. Dormant cyst form
 Trophozoite form: found in intestine or Wall of colon, expelled with stools
 Cyst form: encased by a chitinous wall, protects the organism from environment
 Symptoms: intermittent diarrhea (foul smelling loose/ watery stools),
tenderness and enlargement of liver (with extra intestinal form) to acute
amebic dysentery.
 Many patients- no symptoms- organism remains in body as commensal organism

11. Your text here
Drug Drug Description
Piperazine
A medication used to
treat roundworm and
pinworm.
Amodiaquine An antimalarial drug.
Furazolidone
A drug for the treatment
of infectious diarrhea.
Mebendazole
A benzimidazole
anthelmintic used to
treat helminth infections.

12. Piperazine
 Mechanism of action
Piperazine acts as a γ-aminobutyric acid (GABA)
agonist,causing chloride channel opening, neural
hyperpolarization and flaccid paralysis of susceptible
parasites. Affected worms are then expelled from their
predilection sites by normal enteric movements.

13.  Pharmacokinetics
In humans piperazine is rapidly absorbed and
eliminated after oral administration, being
detected in urine within 30 min, reaching peak
concentrations within 1–8 h and being
undetectable after 24 h.
 Adverse effects
At recommended use rates vomiting, diarrhea,
inappetence and depression may occur.

14. Amodiaquine
 Pharmacodynamics
They depress respiration and cause diplopia, dizziness and
nausea.
Mechanism of action
The mechanism of plasmodicidal action of amodiaquine
is not completely certain. Like other quinoline
derivatives, it is thought to inhibit heme polymerase
activity. This results in accumulation of free heme, which
is toxic to the parasites

15.  Mechanism of action
Furazolidone
Furazolidone also has activity against C. belli and
Trichomonas vaginalis as well as many
enteropathogenic bacteria, and is also used for
treatment of Helicobacter pylori infections. The
mechanism of action involves damage to DNA.
Adverse reactions include diarrhea, fever, nausea
and vomiting.

16.  Furazolidone Effects
A few hypersensitivity reactions to Furoxone (furazolidone) have
been reported including a fall in blood pressure, urticaria, fever,
arthralgia, and a vesicular morbilliform rash.
 Common side effects of Furoxone (furazolidone)
include:
• Lowered blood pressure
• Hives
• Joint Pain
• Rash
• Stomach upset
• Headache
• Vomiting

17. Mebendazole
Mebendazole is a type of medicine for treating worms. It is
used mainly for infections of the gut such as threadworms
(sometimes known as pinworms) and other less common worm
infections (whipworm, roundworm and hookworm). You can
buy mebendazole from a pharmacy. It's also available on
prescription.
 Mechanism of Action
Mebendazole acts by inhibiting the production of microtubules
via binding to colchicine binding-site of β-tubulin and thereby
blocking polymerization of tubulin dimers in the intestinal cells of
parasites.

18. Side Effects
Along with its needed effects, a medicine may cause some
unwanted effects. Although not all of these side effects may
occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side
effects occur:
• Black, tarry stools
• Chills
• Convulsions
• Cough or hoarseness
• Dark urine
• Fever with or without chills
• General feeling of tiredness or weakness
hives or welts, itching, or skin rash

20. Pyrimidine Analogues

21. Pyrimethamine
Uses:
 Used in suppressive treatment and radical cure agent of malaria.
 Acts on both erythrocytic and exoerythrocytic forms of P.falciparum
and exoerythrocytic forms of P.vivax. It is a powerful erythrocytic
schizonticide.
 Combination of pyrimethamine and sulphadoxine- to treat
presumed exposure to P.falciparum and chloroquine- resistant
malaria.
 Combination of pyrimethamine and sulphadiazine- for chloroquine
resistant P.falciparum., toxoplasmosis

22. Folic acid
Reduction
Dihydro folic acid (FAH2)
Dihydrofolate reductase
Tetrahydro folic acid(FAH4)
Precursors
Purine/ Pyrimidine Aminoacids
Mechanism of action:
 Pyrimethamine inhibits the dihydrofolate reductase of malarial parasites.
Metabolism
 Primarily by oxidation to pyrimethamine 3-N oxide

23. WHAT ARE SIDE EFFECTS OF ANTIPARASITIC AGENTS?
• Diarrhea
• Nausea
• Vomiting
• Abdominal pain
• Anorexia (lack or loss of appetite)
• Flatulence (gas)
• Headache
• Unpleasant metallic taste

24. Structure- activity relationship:
 Presence of ethyl group at C-6 is essential for activity.
 Presence of halogen atom, preferably at 4th position is essential
interaction with Dihydro folate reductase enzyme.
 The two six membered rings should not be separaed even by a
single carbon atom.
Pyrimethamine

25. Contraindications and Cautions
The following are contraindications and cautions for the use of
anthelmintics:
• Known allergy to the drug. Prevent hypersensitivity reactions.
• Lactation. Drug can enter breast milk.
• Renal and hepatic disease. Interfere with drug metabolism and
excretion.
• Severe diarrhea and malnourishment. Can alter effects of drug
on the intestine and any preexisting helminths.
• Pyrantel has not been established as safe for use in children
younger than 2 years.

26. Adverse Effects
 Use of anthelmintics may result to these adverse effects:
• GI: abdominal discomfort, diarrhea, pain
• CNS: headache, dizziness,
• Immunologic: fever, shaking, chills, malaise, rash, pruritus, loss of hair
• Albendazole is associated with severe bone marrow depression and renal
failure.

28. REFERENCES
 Text book of organic medicinal & pharmaceutical
chemistry- wilson & gisvold
 Burger’s medicinal chemistry and drug discovery volume v
 Foye’s priniples of medicinal chemistry fifth edition
 Text book of medicinal chemistry- S.PANDEY volume II