therapeutic approach of nursing respiratory pharmacology

1. Respiratory pharmacology
Abdiwahid M.Ismail, Pharm.D
University of Health Science, Bosaso,
Somalia.
1

2. Introduction
• The respiratory system includes the upper
airway passages, the nasal cavities, pharynx
and trachea as well as the bronchi and
bronchioles.
• Respiration is the exchange of gases between
the tissue of the body and to outside
environment.
2

3. Introduction
• It involves breathing in of an air through the
respiratory tract, uptake of oxygen from the
lungs, transport of oxygen through the body in
the blood stream, utilization of oxygen in the
metabolic activities (cells and removal of
carbon dioxide from the body.
• Respiration is the exchange of gases between
the tissue of the body and to outside
environment.
3

4. Introduction
• The chapter will focus on drugs used to treat
some of the more common disorders affecting
the respiratory system particularly bronchial
asthma, allergies and congestions associated
with certain respiratory disorders.
4

5. Bronchial asthma
• Asthma is physiologically characterized by
increased responsiveness of the trachea and
bronchi to various stimuli and by wide spread
narrowing of the airways that changes in
severity either spontaneously or as a result of
therapy.
5

6. Bronchial asthma
Impairment of airflow in bronchial asthma is
caused by three bronchial abnormalities.
I. Contraction of airway smooth muscles
II. Thickening of bronchial mucosa from edema
and cellular infiltration
III. Inspissations in the airway lumen of
abnormally thick, viscid plugs of excessive
mucus.
6

7. Pathogenesis
There are two types of bronchial asthma i.e
extrinsic and intrinsic.
I. Extrinsic asthma is associated with history of
allergies in childhood, family history of
allergies, hay fever, or elevated IgE.
II. Intrinsic asthma occurs in middle-aged
subjects with no family history of allergies,
negative skin tests and normal serum IgE.
7

8. PHARMACOTHERAPY OF BRONCHIAL
ASTHMA
Drug used in the treatment of bronchia asthma can
be grouped into three main categories:
1. Bronchodilators
I. β- Adrenergic agonists which include:
A. Non selective β-agonists e.g. adrenaline
B. Selective β-agonists e.g. salbutamol
II. Methylxanthines; theophylline derivatives
III. Muscranic receptor antagonists e.g. Ipratropium
bromide
8

9. 2. Mast cell stabilizers, e.g. cromolyn sodium,
nedocromil, ketotifen
3. Antiinflammatory agents: corticosteroids
9

10. 1. β- ADRENERGIC AGONISTS
(SYMPATHOMIMETIC AGENTS)
A. Non- selective- β-agonists:- Epinephrine,
ephedrine, isoprotenerol
B. Selective β-agonists :- Salbutamol,
terbutaline, metaproterenol, salmeterol,
formaterol and etc
10

11. Cont…..
They have got several pharmacological actions
important in the treatment of asthma
 Relax smooth muscles
 Inhibit release of inflammatory mediator or
broncho constricting substances from mast
cells.
 Inhibit microvasculature leakage
 Increase mucociliary transport
11

12. A. Non-selective β- agonists
Cause more cardiac stimulation (mediated by a
β1 receptor), they should be reserved for
special situation.
 Epinephrine: very effective, rapidly acting
bronchodilator especially preferable for the
relief of acute attack of bronchial asthma.
 Administered by inhalation or
subcutaneously.
12

13.  Side effects include arrhythmia and worsening of
angina pectoris, increase blood pressure, tremors
etc
 Contraindication: - hypertension, arrhythmia
 Ephedrine: compared to epinephrine, it has
longer duration of action but more pronounced
central effect and lower potency.
 It can be given orally.
 The drug is currently infrequently used because
of development of more efficacious and beta2-
selective agents.
13

14. B. Selective β2- selective agonists
 Largely replaced non – selective β2- agonists,
are effective after inhaled or oral
administration and have got longer duration
of action.
 They are the most widely used
sympathomimetics.
 Commonly used drugs both by oral and
inhalation are Salbutamol, terbutaline,
metaproterenol, pirbuterol and bitolterol.
 Salbutamol and terbutaline are short acting
beta2 agonists used for asthma attacks.
14

15. Cont…….
 Salmeterol and formeterol are new
generation, long acting β2- selective agonists
(with duration of action 12 hrs or more).
 These drugs appear to interact with inhaled
corticosteroids to improve asthma control.
 Delivery of adrenoreceptor agonists through
inhalation results in the greatest local effect
on airway smooth muscle with least systemic
toxicity.
15

16. Side effects, Contraindications,
Precautions
 Side effects :- Tremors, anxiety, insomnia,
tachycardia, headache, hypertension and etc.
 Contraindications: Sympathomimetics are
contraindicated in patients with known
hypersensitivity to the drugs
 Precautions: They should be used cautiously
in patients with hypertension, cardiac
dysfunction, hyperthyroidism, glaucoma,
diabetes, pregnancy.
16

17. 2. METHYLXANTHINES
 The three important methylxanthines are
theophylline, theobromine, and caffeine.
 The theophylline preparations most
commonly used for therapeutic purposes is
aminophylline (theophylline plus
diethylamine).
 Mechanism of action: direct bronchodilators.
17

18. Pharmacokinetics
 Only slightly soluble in water so has been
administered as several salts containing
varying amounts of theophylline base.
 Most preparations are well absorbed from
gastro intestinal tract and metabolized by liver.
 Doses should be decreased in cases of liver
disease and heart failure.
18

19. Adverse Effects:
 Anorexia, nausea, vomiting, abdominal
discomfort, headache, anxiety, insomnia,
seizures, arrhythmias.
 Theophylline is now largely reserved for
patients in whom symptoms remain poorly
controlled despite the combination of regular
treatment with an inhaled anti- inflammatory
agent and as needed use of a ß2 agonist.
19

20. 3. MUSCRANIC RECEPTOR
ANTAGONISTS
 Muscarinic antagonist competitively inhibit
effect of acetylcholine at muscarinic receptors
– hence block the contraction of air way
smooth muscle and the increase in secretion
of mucus that occurs in response to vagal
activity e.g atropine sulfate
20

21. Cont….
 Systemic adverse effects as a result of rapid
absorption include urinary retention,
tachycardia, loss of accommodation and
agitation and local effects like excessive dryness
of mouth limits the quantity of atropine used.
 Ipratropium bromide is poorly absorbed and
does not readily enter the central nervous
system thus permits the delivery of high doses to
muscarinic receptor in the airways; hence, it can
safely be used for bronchial asthma.
21

22. Cont…….
 Antimuscranic antagonist drugs appear to be
slightly less effective than β- agonists agents in
reversing asthmatic bronchospasm.
 The addition of ipratropium enhances the
bronchodilatation produced by nebulized
albuterol in acute sever asthma.
• The antimuscarinic agents appear to be of
significant value in chronic obstructive pulmonary
diseases - perhaps more than asthma.
• They are useful as alternative therapies for
patients intolerant of β – agonists.
22

23. 4. ANTI-INFLAMMATORY AGENTS:
CORTICOSTEROIDS
 Used both for treatment and prophylactic
purposes
Effects on airway
 decreases bronchial reactivity
 increases airway diameter
 decreases frequency of asthma exacerbation
and severity of symptoms
23

24. Cont….
 The corticosteroids commonly used are
hydrocortisone, predinisolone,
beclomethasone,triamcinolone and etc.
 The drugs can be taken by inhalation as
aerosol, oral, or an IV administration.
24

25. Cont…
 Because of severe adverse effects when given
chronically, oral and parenteral corticosteroids
are reserved for patient who need urgent
treatment and those who have not improved
with bronchodilator.
 Aerosol treatment is the most effective way to
decrease the systemic adverse effect of
corticosteroid therapy.
25

26. Cont….
 Abrupt discontinuation should be discouraged
because of the fear of adrenal insufficiency.
 Doses should be decreased after
improvement.
 Regular or controlled therapy is better
maintained with aerosol corticosteroids.
26

27. Clinical uses in bronchial asthma
Urgent treatment of severe asthma not
improved with bronchodilator
-IV, inhalation or oral.
Nocturnal asthma prevention
- oral or inhalation
Chronic asthma
- Regular aerosol corticosteroids
27

28. Side effects:
 Suppression of the hypothalamic-pituitary-
adrenal axis.
 Osteoporosis.
 Sodium retention and hypertension.
 Cataract.
 Impairment of growth in children.
 Susceptibility to infection like oral candidiasis,
tuberculosis.
28

29. 5. MAST CELL STABILIZERS
• E.g cromolyn sodium, Nedocromil sodium.
Mechanism of action
• Stabilize the mast cells so that release of
histamine and other mediators is inhibited
through alteration in the function of delayed
chloride channel in cell membrane.
• It has no role once mediator is released and is
used for casual prophylaxis.
29

30. Cont….
Clinical uses
• Exercise and antigen induced asthma
• Occupational asthma
Side effects
• Poorly absorbed so minimal side effect
• Throat irritation, cough, dryness of mouth,
chest tightness and wheezing
30

31. TREATMENT OF STATUS ASTHMATICS
Status asthmatics:- Very severe and sustained
attack of asthma which fails to respond to
treatment with usual measures.
31

32. Cont….
Management includes:
 Administration of oxygen
 Frequent or continuous administration of
aerosolized ß2 agonists like salbutamol
 Systemic corticosteroid like methyl
prednisolone or hydrocortisone IV
 Aminophylline IV infusion
 Iv fluid to avoid dehydration
 Antibiotics in the presence of evidence of
infection
32

33. ANTI-TUSSIVES
• Cough is a protective reflex, which serves the purpose
of expelling sputum and other irritant materials from
the respiratory airway.
Types:
 Useful productive cough
Effectively expels secretions and exudates
 Useless cough
Non-productive chronic cough
Due to smoking and local irritants
 Anti-tussives are drugs used to suppress the intensity
and frequency of coughing.
33

34. Two Types of Anti-tussives:
1. Central anti- tussives : suppress the cough
center in the medulla and may be divided
into two groups:
A. addictive antitussive e.g. codeine,
hydrocodeine, etc
B. Non addictive antitussives e.g.
dextromethorphan
34

35. Cont….
2. Peripheral antitussives :- decrease the input
of stimuli from the cough receptor in the
respiratory passage. e.g: Demulcents e.g.
liquorices lozenges, honey
Local anesthetics e.g. lidocaine aerosol.
 Demulcents coat the irritated pharyngeal
mucosa and exert a mild analgesic effect
locally.
35

36. Cont..
CODEINE
 Codeine is a narcotic relatively less addicting drug
and central antitussive agent.
 It’s main side effects are dryness of mouth,
constipation and dependence.
DEXTROMETROPHAN
 Dextromethorphan is an opoid synthetic
antitussive, essentially free of analgesic and
addictive properties.
 The main side effects are respiratory depression.
36

37. Cont….
Expectorant: is a drug that aid in removing
thick tenacious mucus from respiratory
passages, e.g. Ipecac alkaloid, sodium citrate,
saline expectorant, guanfenesin, potassium
salts.
Mucolytics: are agents that liquefy mucus and
facilitate expectoration, e.g.acetylcysteine.
37

38. DECONGESTANTS
 Decongestants are the drugs that reduce
congestion of nasal passages, which in turn
open clogged nasal passages and enhances
drainages of the sinuses.
 e.g phenylephrine, oxymetazoline etc.
38

39. Cont…
Mechanism of Action:
 Mucus membrane decongestants are α1 agonists,
which produce localized vasoconstriction on the small
blood vessels of the nasal membrane.
 Reduce congestion in nasal passages.
Clinical uses:
 Used in congestion associated with rhinitis, hay fever,
allergic rhinitis and to a lesser extent common cold.
 Drugs can be administered nasally or orally for longer
duration of action.
39

40. Classification
1. Short acting decongestants administered
topically – phenylepherne,
phenylpropanolamine
2. Long acting decongestants administered
orally - ephedrine, pseudoephedrine,
naphazoline.
3. Long acting topical decongestants
-Xylometazoline
- oxymetazoline
40

41. Cont…..
Side effects :-
 Rebound nasal congestion
 Ischemic changes in mucus membranes
 Nasal burning, stinging, dryness
 Tachycardia, arrhythmia, nervousness,
restlessness, insomnia, blurred vision.
Contraindications:-
 Hypertension,
 severe coronary artery disease
41

42. Treatment of common cold
 Over-the-counter cold and cough medicines may
help ease symptoms in adults and older children.
 Nasal decongestents :
-Oxymetazoline
-Phenylephrin
 Analgesics
-Acetaminophen
-Ibuprofen
 Take plenty of fluids
42

43. BRONCHITIS
• Bronchitis refers to an inflammatory condition of
the large elements of the tracheobronchial tree
that is usually associated with a generalized
respiratory infection.
• The inflammatory process does not extend to
include the alveoli.
• The disease entity is frequently classified as
either acute or chronic.
• Acute bronchitis occurs in all ages, whereas
chronic bronchitis primarily affects adults.
43

44. Acute Bronchitis
• Acute bronchitis most commonly occurs
during the winter months.
• Cold, damp climates and/or the presence of
high concentrations of irritating substances
such as air pollution or cigarette smoke may
precipitate attacks.
44

45. • Respiratory viruses are by far the most common
infectious agents associated with acute bronchitis.
• The common cold viruses, rhinovirus and
coronavirus, and lower respiratory tract
pathogens, including influenza virus, adenovirus,
and respiratory syncytial virus, account for the
majority of cases.
• Mycoplasma pneumoniae also appears to be a
frequent cause of acute bronchitis.
• Other bacterial causes include Chlamydia
pneumoniae and Bordetella pertussis.
45

46. Desired Outcome
• The goals of therapy are to provide comfort to
the patient and, in the unusually severe case,
to treat associated dehydration and
respiratory compromise.
46

47. Treatment
• The treatment of acute bronchitis is
symptomatic and supportive in nature.
• Reassurance and antipyretics alone are often
sufficient.
• Bedrest and mild analgesic-antipyretic
therapy are often helpful in relieving the
associated lethargy, malaise, and fever.
• Patients should be encouraged to drink fluids
to prevent dehydration and possibly decrease
the viscosity of respiratory secretions. 47

48. • Aspirin or acetaminophen (650 mg in adults
or 10 to 15 mg/kg per dose in children with a
maximum daily adult dose of 4 g and 60
mg/kg for children) or ibuprofen (200 to 800
mg in adults or 10 mg/kg per dose in children
with a maximum daily dose of 3.2 g for adults
and 40 mg/kg for children) is administered
every 4 to 6 hours.
48

49. • In children, aspirin should be avoided and
acetaminophen used as the preferred agent
because of the possible association between
aspirin use and the development of Reye’s
syndrome.
• Mist therapy and/or the use of a vaporizer may
further promote the thinning and loosening of
respiratory secretions.
• Persistent, mild cough, which may be
bothersome, may be treated with
dextromethorphan; more severe coughs may
require intermittent codeine or other similar
agents.
49

50. • Routine use of antibiotics in the treatment of
acute bronchitis is discouraged; however, in
patients who exhibit persistent fever or
respiratory symptomatology for more than 4 to 6
days, the possibility of a concurrent bacterial
infection should be suspected.
• When possible, antibiotic therapy is directed
toward anticipated respiratory pathogen(s) (i.e.,
Streptococcus pneumoniae, Haemophilus
influenzae) and/or those demonstrating a
predominant growth upon throat culture.
50

51. • M. pneumoniae, if suspected by history or
positive culture , may be treated with
azithromycin.
• Also, a fluoroquinolone with activity against
these pathogens (levofloxacin) may be used
in adults.
• During known epidemics involving the
influenza A virus, amantadine or rimantadine
may be effective in minimizing associated
symptomatology if administered early in the
course of the disease.
51

52. CHRONIC BRONCHITIS
• Chronic bronchitis is a result of several
contributing factors, including cigarette
smoking; exposure to occupational dusts,
fumes, and environmental pollution; and
bacterial (and possibly viral) infection.
• The hallmark of chronic bronchitis is cough
that may range from a mild “smoker’s” cough
to severe incessant coughing productive of
purulent sputum.
52

53. Cont……
• By definition, any patient who reports
coughing up sputum on most days for at least
3 consecutive months each year for 2
consecutive years suffers from chronic
bronchitis.
53

54. Common bacterial causes of Chronic
Bronchitis
54

55. Desired Outcome
• The goals of therapy for chronic
bronchitis are to reduce the severity of
symptoms, to ameliorate acute
exacerbations, and to achieve prolonged
infection-free intervals.
55

56. Treatment
• Oral or aerosolized bronchodilators (e.g.,
albuterol aerosol) may be of benefit to some
patients during acute pulmonary exacerbations.
• For patients who consistently demonstrate
limitations in airflow, a therapeutic change of
bronchodilators should be considered.
• Long-term inhalation of Ipratropium decreases
the frequency of cough, severity of cough, and
the volume of expectorated sputum.
56

57. • The use of antimicrobials has been
controversial, although antibiotics are an
important component of treatment.
• Agents should be selected that are effective
against likely pathogens, have the lowest risk
of drug interactions, and can be administered
in a manner that promotes compliance (see
Table 43-3).
• Selection of antibiotics should consider that
up to 30% to 40% of H. influenzae and 95% of
M. pneumoniae are β-lactamase producers,
and up to 30% of S. pneumoniae are at least
moderately penicillin resistant.
57

58. • Duration of symptom-free periods may be
enhanced by antibiotic regimens using the upper
limit of the recommended daily dose for 5 to 7
days.
• In patients whose history suggests recurrent
exacerbations of their disease that might be
attributable to certain specific events (i.e.,
seasonal, winter months), a trial of prophylactic
antibiotics might be beneficial.
• If no clinical improvement is noted over an
appropriate period (e.g., 2 to 3 months per year
for 2 to 3 years), prophylactic therapy could be
discontinued. 58

59. 59

60. BRONCHIOLITIS
• Bronchiolitis is an acute viral infection of
the lower respiratory tract of infants that
affects approximately 50% of children
during the first year of life and 100% by 3
years.
• Respiratory syncytial virus is the most
common cause of bronchiolitis, accounting
for up to 70% of all cases.
• Parainfluenza viruses are the second most
common cause. Bacteria serve as secondary
pathogens in only a small minority of cases.60

61. Treatment
• Bronchiolitis is a self-limiting illness and
usually requires no therapy (other than
reassurance and antipyretics) unless the infant
is hypoxic or dehydrated.
• Otherwise healthy infants can be treated for
fever, provided generous amounts of oral
fluids, and observed closely.
• In severely affected children, the mainstays of
therapy for bronchiolitis are oxygen therapy
and IV fluids.
61

62. • Aerosolized β-adrenergic therapy appears to
offer little benefit for the majority of patients
but may be useful in the child with a
predisposition toward bronchospasm.
• Because bacteria do not represent primary
pathogens in the etiology of bronchiolitis,
antibiotics should not be routinely
administered. However, many clinicians
frequently administer antibiotics initially while
awaiting culture results because the clinical
and radiographic findings in bronchiolitis are
often suggestive of a possible bacterial
pneumonia.
62

63. • Ribavirin may be considered for
bronchiolitis caused by respiratory
syncytial virus in a subset of patients
(those with underlying pulmonary or
cardiac disease or with severe acute
infection).
63

64. PNEUMONIA
• Pneumonia is the most common infectious cause
of death.
• It occurs in persons of all ages, although the
clinical manifestations are most severe in the very
young, the elderly, and the chronically ill.
• Microorganisms gain access to the lower
respiratory tract by three routes:
they may be inhaled as aerosolized particles;
they may enter the lung via the bloodstream
from an extrapulmonary site of infection; or
aspiration of oropharyngeal contents may occur.64

65. • Lung infections with viruses suppress the
bacterial clearing activity of the lung by
impairing alveolar macrophage function and
mucociliary clearance, thus setting the stage
for secondary bacterial pneumonia.
• The vast majority of pneumonia cases
acquired in the community by otherwise
healthy adults are due to S. pneumoniae
(pneumococcus) (up to 75% of all acute
bacterial pneumonias in the United States).
65

66. • Other common bacterial causes include M.
pneumoniae, Legionella , and C. pneumoniae,
which are referred to as “atypical” pathogens.
• Community-acquired pneumonias caused by
Staphylococcus aureus and gram-negative
rods are observed primarily in the elderly,
especially those residing in nursing homes,
and in association with alcoholism and other
debilitating conditions.
66

67. • Gram-negative aerobic bacilli and S.
aureus are also the leading causative
agents in hospital-acquired
pneumonia.
• Anaerobic bacteria are the most
common etiologic agents in
pneumonia that follows the gross
aspiration of gastric or
oropharyngeal contents.
67

68. • In the pediatric age group, most
pneumonias are due to viruses,
especially respiratory syncytial virus,
parainfluenza, and adenovirus.
Pneumococcus is the most common
bacterial cause, followed by Group A
Streptococcus and S. aureus.
68

69. DESIRED OUTCOME
• Eradication of the offending organism
and complete clinical cure are the
primary objectives.
• Associated morbidity should be
minimized (e.g., renal, pulmonary, or
hepatic dysfunction).
69

70. TREATMENT
• The first priority on assessing the
patient with pneumonia is to evaluate
the adequacy of respiratory function
and to determine whether there are
signs of systemic illness, specifically
dehydration or sepsis with resulting
circulatory collapse.
70

71. Cont….
• The supportive care of the patient
with pneumonia includes the use of
humidified oxygen for hypoxemia,
fluid resuscitation, administration of
bronchodilators when bronchospasm
is present, and chest physiotherapy
with postural drainage if there is
evidence of retained secretions. 71

72. 72

73. 73

74. 74

75. Tuberculosis
• Tuberculosis (TB) is a communicable infectious
disease caused by Mycobacterium tuberculosis.
• It can produce silent, latent infection as well as
progressive, active disease.
• Globally, 2 billion people are infected and 2
million to 3 million people die from TB each
year.
• M. tuberculosis is transmitted from person to
person by coughing or sneezing.
• Close contacts of TB patients are most likely to
become infected.
75

76. • Human immunodeficiency virus (HIV) is
the most important risk factor for active
TB, especially among people 25 to 44
years of age.
• An HIV infected individual with TB
infection is over 100-fold more likely to
develop active disease than an HIV-
seronegative patient.
76

77. • Primary infection is initiated by the
alveolar implantation of organisms in
droplet nuclei that are small enough (1
to 5 mm) to escape the ciliary epithelial
cells of the upper respiratory tract and
reach the alveolar surface.
77

78. • Once implanted, the organisms multiply
and are ingested by pulmonary
macrophages, where they are killed, or,
they continue to multiply.
• With bacterial multiplication, the
macrophages eventually rupture,
releasing many bacilli.
78

79. • Large numbers of activated macrophages
surround the solid caseous (cheese-like) TB
foci (the necrotic area) as a part of cell-
mediated immunity.
• Delayed-type hypersensitivity also develops
through activation and multiplication of T
lymphocytes. Macrophages form
granulomas to contain the organisms.
79

80. DESIRED OUTCOME
• Rapid identification of new cases of TB
• Isolation of the patient with active disease to prevent
spread
• Collection of appropriate samples for smears and
cultures
• Prompt resolution of signs and symptoms of disease
after initiation of treatment
• Achievement of a noninfectious state, thus ending
isolation
• Adherence to the treatment regimen
• Cure as quickly as possible (generally with at least 6
months of treatment)
80

81. TREATMENT
GENERAL PRINCIPLES
• Drug treatment is the cornerstone of TB
management.
• A minimum of two drugs, and generally three or
four drugs, must be used simultaneously.
• Drug treatment is continued for at least 6
months and up to 2 to 3 years for some cases of
multidrug-resistant TB (MDR-TB).
• Measures to assure adherence, such as directly
observed therapy, are important.
81

82. • Patients with active disease should be isolated
to prevent spread of the disease.
• Public health departments are responsible for
preventing the spread of TB, finding where TB
has already spread using contact investigation.
• Debilitated patients may require therapy for
other medical conditions, including substance
abuse and HIV infection, and some may need
nutritional support.
• Surgery may be needed to remove
destroyed lung tissue, space-occupying
lesions, and some extrapulmonary lesions.
82

83. PHARMACOLOGIC TREATMENT
Latent Infection
• As described in Table 49-3, chemoprophylaxis
should be initiated in patients to reduce the risk
of progression to active disease.
• Isoniazid (INH) 300 mg daily in adults is the
preferred treatment for latent TB in the United
States, generally given for 9 months.
• Individuals likely to be noncompliant may be
treated with a regimen of 15 mg/kg (to a
maximum of 900 mg) twice weekly with
observation.
83

84. • Rifampin (RIF) 600 mg daily for 4 months can
be used when INH resistance is suspected or
when the patient cannot tolerate INH.
• Rifabutin 300 mg daily may be substituted for
RIF for patients at high risk of drug
interactions.
• Pregnant women, alcoholics, and patients
with poor diets who are treated with INH
should receive pyridoxine, 10 to 50 mg daily,
to reduce the incidence of CNS effects or
peripheral neuropathies.
84

85. 85

86. Treating Active Disease
• Table 49-4 lists options for treatment of
culture-positive pulmonary TB caused by drug-
susceptible organisms.
• Doses of antituberculosis drugs are given in
Table 49-5.
• The standard TB treatment regimen INH, RIF,
pyrazinamide, and ethambutol for 2 months
followed by INH and RIF for 4 months.
86

87. • Appropriate samples should be sent for culture
and susceptibility testing prior to initiating
therapy for all patients with active TB.
• This data should guide the initial drug selection
for the new patient.
• If susceptibility data are not available, the drug
resistance pattern in the area where the patient
likely acquired TB should be used.
• If the patient is being evaluated for the
retreatment of TB, it is imperative to know
what drugs were used previously and for how
long. 87

88. • Patients must complete 6 months or more of
treatment.
• HIV-positive patients should be treated for an
additional 3 months and at least 6 months
from the time that they convert to smear and
culture negativity.
• When INH and RIF cannot be used, treatment
duration becomes 2 years or more, regardless
of immune status.
88

89. • Patients who are slow to respond, those
who remain culture positive at 2 months
of treatment, those with cavitary lesions
on chest radiograph, and HIV-positive
patients should be treated for 9 months
and for at least 6 months from the time
they convert to smear and culture
negativity.
89

90. 90

91. 91

92. 92

93. 93

94. Drug Resistance
• If the organism is drug resistant, the aim
is to introduce two or more active
agents that the patient has not received
previously.
• With MDR-TB, no standard regimen can
be proposed.
• It is critical to avoid monotherapy or
adding only a single drug to a failing
regimen.
94

95. • Drug resistance should be suspected in
the following situations:
Patients who have received prior
therapy for TB
Patients from geographic areas with a
high prevalence of resistance
 Patients who are homeless,
institutionalized, IV drug abusers,
and/or infected with HIV
95

96.  Patients who still have acid-fast
bacilli–positive sputum smears after 2
months of therapy
 Patients who still have positive
cultures after 2 to 4 months of
therapy
Patients who fail therapy or relapse
after retreatment
 Patients known to be exposed to
MDR-TB cases
96

97. Special Populations
Tuberculous Meningitis and Extrapulmonary
Disease
• In general, INH, pyrazinamide, ethionamide,
and cycloserine penetrate the cerebrospinal
fluid readily. Patients with CNS TB are often
treated for longer periods (9 to 12 months).
• Extrapulmonary TB of the soft tissues can be
treated with conventional regimens.
• TB of the bone is typically treated for 9
months, occasionally with surgical
debridement.
97

98. Children
• TB in children may be treated with
regimens similar to those used in
adults, although some physicians still
prefer to extend treatment to 9
months.
• Pediatric doses of drugs should be
used.
98

99. Pregnant Women
• The usual treatment of pregnant women is INH,
RIF, and ethambutol for 9 months.
• Women with TB should be cautioned against
becoming pregnant, as the disease poses a risk
to the fetus as well as to the mother.
• INH or ethambutol are relatively safe when used
during pregnancy.
99

100. • Supplementation with B vitamins is
particularly important during pregnancy.
• RIF has been rarely associated with birth
defects, but those seen are occasionally
severe, including limb reduction and CNS
lesions.
100

101. • Pyrazinamide has not been studied in a large
number of pregnant women, but anecdotal
information suggests that it may be safe.
• Ethionamide may be associated with
premature delivery, congenital deformities,
and Down’s syndrome when used during
pregnancy.
• Streptomycin has been associated with
hearing impairment in the newborn,
including complete deafness.
• Cycloserine is not recommended during
pregnancy.
101

102. Renal Failure
• In nearly all patients, INH and RIF do
not require dose modifications in
renal failure.
• Pyrazinamide and ethambutol
typically require a reduction in
dosing frequency from daily to three
times weekly (Table 49-6).
102

103. 103

104. Refrences
• Dipiro pharmacotherapy
• Basic and clinical pharmacology ,Katzung
• Other internet sources.
104