Series of Pharmacology lectures to undergraduate medical students, based on illustrations and hints that aid studying from standard textbook.

1. CHEMOTHERAPY
HIGHLIGHTS
MOHAMED BAHR; MD, PHD
Antiprotozoal Drugs

2. Mohamed Bahr; MD, PhD
ANTIPROTOZOAL
DRUGS

3. Mohamed Bahr; MD, PhD
ANTIAMEBIC
DRUGS

4. Mohamed Bahr; MD, PhD

5. Mohamed Bahr; MD, PhD
AMEBIASIS
Bowel lumen amebiasis: asymptomatic (carriers or cyst
passers), may become symptomatic if left untreated.
Tissue amebiasis: cysts develop into trophozoites which feed
on intestinal bacteria or invade submucosa of large intestine,
resulting in:
• Intestinal infection: mild to moderate colitis (no dysentery) or
severe (dysentery).
• Amebic granuloma (ameboma) in intestinal wall.
• Extra-intestinal amebiasis: liver abscess, pulmonary amebiasis…

6. Mohamed Bahr; MD, PhD
1. DILOXANIDE
1st choice luminal amebicide used for:
asymptomatic luminal infections
tissue amebiasis, in combination with tissue amebicides, to
eradicate the source of infection
Side effects: GIT flatulence - nausea - abdominal cramps.
Teratogenic.

7. Mohamed Bahr; MD, PhD
2. IODOQUINOL
Alternative to diloxanide.
Also used in giardiasis.
Adverse Effects
GIT upset: nausea, vomiting, diarrhea.
SMON.
Thyroid enlargement.

8. Mohamed Bahr; MD, PhD
3. PAROMOMYCIN
(REMAINS IN GIT LUMEN)
GIT

9. Mohamed Bahr; MD, PhD
1. METRONIDAZOLE
(FLAGYL)
It is a prodrug which is activated by reduction of
its NITRO group → disruption of DNA structure and
function → cell death.

10. Mohamed Bahr; MD, PhD
USES
Anaerobic protozoal infections:
• Amebiasis (all forms except asymptomatic cyst passers).
• Others: Giardiasis - Trichomoniasis (urogenital).
Anaerobic bacterial infections:
• Pseudomembranous colitis due to Clostridium difficile.
• Brain abscess, ulcerative gingivitis and dental infections, leg
ulcers.

11. Mohamed Bahr; MD, PhD
ADVERSE EFFECTS
GIT: unpleasant metallic taste, glossitis, stomatitis, nausea and
vomiting.
CNS (serious): dizziness - vertigo - ataxia - neuropathy -
convulsions.
Dark urine - dysuria.
Neutropenia.
Teratogenic
Enzyme inhibitor: ↑ warfarin level.

12. Mohamed Bahr; MD, PhD
2. TINIDAZOLE
(FASIGYN)
Similar to metronidazole but more effective, longer t ½, and
less teratogenic.

13. Mohamed Bahr; MD, PhD
3. CHLOROQUINE
LIVER

14. Mohamed Bahr; MD, PhD
4. EMETINE AND
DEHYDROEMETINE
Remember: Amphotericin
Severe

15. Mohamed Bahr; MD, PhD
5. TETRACYCLINES
Mild

16. Mohamed Bahr; MD, PhD

17. Mohamed Bahr; MD, PhD
ANTIMALARIAL
DRUGS

18. Mohamed Bahr; MD, PhD

19. Mohamed Bahr; MD, PhD
PROBLEMS
1. Chloroquine resistance: chloroquine is the mainstay of
antimalarial therapy, but resistance to drug
(geographically distributed) is a major problem especially
with P falciparum (most dangerous → encephalopathy
and renal failure).
2. Relapse: re-activation of dormant form in hepatic cells →
relapses in P ovale and P vivax, not in P falciparum.

20. Mohamed Bahr; MD, PhD

21. Mohamed Bahr; MD, PhD
I. 4-AMINOQUINOLINES

22. Mohamed Bahr; MD, PhD
CHLOROQUINE

23. Mohamed Bahr; MD, PhD
ADVERSE EFFECTS
GIT: nausea, vomiting and diarrhea.
Hypersensitivity: pruritis (most common).
CNS…
Neutropenia.
Cardiotoxic: quinidine-like action (hypotension and arrhythmias).
Eye: corneal opacity, blurred vision and retinopathy.
Ototoxicity
Hemolytic Anemia: in G6PD-deficient subjects.

24. Mohamed Bahr; MD, PhD
QUININE AND
QUINIDINE
Cardiotoxic: Quinidine-like action → hypotension and
arrhythmias.
Eye → blurred vision and blindness.
Cinchonism: tinnitus - headache - dizziness and visual
disturbances.
Black water fever and hemolysis.
Uterus: abortion.
Not in Prophylaxis!

25. Mohamed Bahr; MD, PhD
QUININE AND
QUINIDINE
Alternatives

26. Mohamed Bahr; MD, PhD
MEFLOQUINE
Excellent Alternative

27. Mohamed Bahr; MD, PhD
II. HALOFANTRINE
Cardiotoxic
Alternative

28. Mohamed Bahr; MD, PhD
III. 8-
AMINOQUINOLINES:
PRIMAQUINE
Radical cure
Terminal
prophylaxis
Gametocidal

29. Mohamed Bahr; MD, PhD
G6PD
Teratogenic

30. Mohamed Bahr; MD, PhD
IV. ANTIFOLATE
ANTIMALARIAL DRUGS
Blood schizonticides (mainly)
1ry tissue schizonticides
sporontocides

31. Mohamed Bahr; MD, PhD
Treatment of chloroquine-resistant falciparum (fansidar plus
quinine).
Prophylaxis in all types (proguanil + chloroquine).

32. Mohamed Bahr; MD, PhD
ADVERSE EFFECTS
GIT
G6PD
Remember: TMP

33. Mohamed Bahr; MD, PhD
Treatment Prophylaxis
Chloroquine-
Sensitive P
falciparum
Chloroquine
P vivax and
ovale
Chloroquine
then
Primaquine
(radical cure and terminal prophylaxis)
Chloroquine-
Resistant P
falciparum
Quinine + Fansidar (or
Doxycyline)
or
Mefloquine
or
Halofantrine
 Mefloquine
or
 Proguanil plus chloroquine
 Doxycyline (in multidrug
resistant cases)

34. Mohamed Bahr; MD, PhD
DRUGS FOR
CHEMOPROPHYLAXIS
ARE GIVEN:
for 2 wks (chloroquine, mefloquine) or for 2 days
(proguanil or doxycyline) before travel
AND
for 4 wks after leaving endemic area.

35. Mohamed Bahr; MD, PhD

36. Mohamed Bahr; MD, PhD
ANTITRYPANOSOMAL
DRUGS

37. Mohamed Bahr; MD, PhD

38. Mohamed Bahr; MD, PhD

39. Mohamed Bahr; MD, PhD
REFERENCES
Lippincott’s Illustrated Reviews, 5th ed.
Color Atlas of Pharmacology, 2nd ed.
Goodman and Gilman's The Pharmacological Basis of
Therapeutics, 12th ed.