Antihistamine Drugs

1. ANTI HISTAMINES
PREPARED BY:
USHA RANI KANDULA,
ASSISTANT PROFESSOR,
DEPARTMENT OF ADULT HEALTH NURSING,
ARSI UNIVERSITY,ASELLA,ETHIOPIA,
SOUTH EAST AFRICA.

2. Anti histamines
 Histamine is an important
chemical mediator that is stored
in mast cell located in almost all
body tissue.

3.  Histamine is released in response
to antigen for which a person has
developed antibodies.

4. The effect of histamine include :
 Contraction of smooth muscle in
the bronchi, GI tract and uterus
 Vasodilatation and increased
capillary permeability ( edema)

5.  Increased secretion of gastric
juice, increased bronchial,
intestinal and salivary secretion.
 Pain and itching caused by
sensory nerve stimulation.

6.  Antihistamine prevents the effect
of histamine by occupying the
histamine receptors.

7.  The two types of histamine
receptors are H1 and H2receptors.
 H1receptors : are those
associated with the smooth
muscle of the blood vessels,
bronchioles, GI tract.

8.  H2 receptors : are found on
gastric parietal cells, the
myocardium and certain blood
vessels.

9. MECHANISM OF ACTION

10.  Antihistamines are H1 antagonists
and produce the following effects
:
 1. smooth muscles : H1
anatagonist effectively inhibits
the response of smooth muscles
to histamine.

11.  In the vascular smooth muscles,
the H1 antagonist inhibit the
vasoconstrictor effect of
histamine on the large blood
vessels.

12.  2. capillary permeability:
 H1 antagonist blocks the action of
histamine, which leads to
increase leakage of plasma.

13.  3. Nerve endings :
 H1antagonist effectively blocks
the action of histamine on nerve
endings, which cause itching and
flare.

14.  4. Anaphylaxis and allergy :
 Many manifestations of type I
(immediate ) hypersensitivity
reaction like
 -urticaria
 -pruritis and angioedema are well
controlled by H1 antagonists.

15. COMMONLY USED ANTIHISTAMINES
- AZATADINE : 1-2 MG/ORAL
- CARBINOXAMINE :
ADULTS : 4-8 MG/ORAL
CHILDREN : 2-6 MG/ORAL

16. -PHENIRAMINE MALEATE
(CHLORPHENIRAMINE ) :
-4MG ORAL/IV

17. -DEXCHLOR PHENIRAMINE
( POLARAMINE) :
-ADULTS 2 MG ORAL
-DIMENHYDRINATE :
-ADULTS 50-100MG
-CHILDREN 25-50 MG

18. -DIPHENHYDRAMINE
( BENADRYL)
ADULTS : 25-50 MG
CHILDREN : 5MG/KG/DAY
ORAL / IV / DEEP IM

19. -PHENINDAMINE
25 MG ORAL
-PROMETHAZINE
( PHENERGAN)
12.5 – 50 MG ORAL / IM

20. -CETRIZINE
(LEVOCETIRIZINE)
10 MG ORAL
-LORATADINE
10-20 MG ORAL
-FEXOFENADINE
150-250 MG ORAL

21. INDICATIONS

22. INDICATIONS
 Allergic disorders
 Allergic rhinitis
 Common cold
 Insect bites
 Drug reactions
 Anaphylactic reactions

23.  Allergic cough
 Urticaria
 Pruritis
 Nausea and vomiting

24. USES

25. USES
 Allergic reactions to transfusion
of blood or blood products.

26. CONTRAINDICATIONS

27. Contraindications
 Narrow-angle glaucoma
 Prostatic hypertrophy
 Bladder neck obstruction
 Peptic ulcer disease

28.  Asthma
 Pregnant women
 Dehydrated children
 Premature infants

29. SIDE EFFECTS

30. SIDE EFFECTS
 Sedation
 Dizziness
 Epigastric distress
 Dryness of mouth
 Thickened bronchial secretions

31. NURSING
RESPONSIBILITIES

32. Nursing responsibilities
 Monitor for therapeutic and
adverse effects.
 Administer IV slowly to prevent
severe hypotension.
 Give antihistamines with food to
decrease GI distress.

33.  Assess client for drowsiness
during first few days of therapy.
 Administer medications at bed
time to help with the side effect of
drowsiness.

34. PATIENT EDUCATION

35. Patient education
 Take medications exact as
prescribed.
 Avoid contact with allergens,
responsible for the reaction.
 Do not take more than one
medication at a time.

36.  Do not operate heavy machinery
or participate in other hazardous
activities while taking this type of
medications.

37. THANKING YOU