Download DRUGS ACTING ON THE RESPIRATORY SYSTEMS

UNIVERSITY OF LUSAKA
DRUGS ACTING ON THE RESPIRATORY
SYSTEM
ANTIHISTAMINES
• Histamine: is a chemical neuro-transmitter
your body produces in response to an allergic
reaction.In certain allergic rxns like a sting by a
bee ,the levels are so high that if not treated
can lead to anaphylactic shock and possibly
death.Histamine triggers inflammatory
response .As part of an immune response to
foreign pathogens,histamine is produced by
the mast cells and basophils found in
connective tissue.
ROLES OF HISTAMINE IN THE BODY
• Plays a role in sleep regulation
• Plays a role erection and sexual function: as
evidenced by certain antihistamine drugs e.g
cimetidine and ranitidine
• Histamine mainly present in the pituitary and
hypothalamus.Both types of histamine
receptors(H1 and H2) are present.The function
s of the histaminergic system remain
uncertain.
CLASSIFICATION OF ANTIHISTAMINES
• Classified as H1 and H2 blockers.
• H1 RECEPTOR BLOCKERS: ALKYLAMINES:
brompheniramine,chlorpheniramine,triprolidi
ne.ETHANOLAMINES: diphenhydramine,
PHENOTHIAZINES:promethazine ,PIPERIDINES:
cyclizine,PIPERIDINES: cyproheptdine
OTHERS:cyproheptadine. SECOND
GENERATION”s INCLUDE:loratidine,astemizole
and cetirizine.
H2 RECEPTOR BLOCKER
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Cimetidine
Ranitidine
Famotidine
Nizatidine
H3 RECEPTOR BLOCKERS INCLUDE:
Thioperamide,Impromidine
• Therapeutic classfication can be drugs used to
treat ulcers(cimetidine),motion sickness(cyclizine)
THERAPAUTIC CLASSIFICATION
CONT”D
• Donianrugs used in
insomia(diphenhydramine),drugs used in
vertigo(cyclizine)drugs used for
allergy(loratidine)antiparkinsonian(orphenadri
ne)local anaesthetics(mepyramine)
• SIDE EFFECTS: dry
mouth,drowsiness,dizziness,nausea and
vomiting,restlessness,inability to
urinate,blurred vision and confusion.
DRUG THERAPY FOR ASTHMA
(BRONCHODILATORS)
• Bronchial asthma is a disease affecting all age
groups,characterised by increased
responsiveness of the trachea and bronchi to a
variety of chemical or physical stimuli.
• PATHOLOGICAL CHANGES AND CLINICAL
MANIFESTATIONS: bronchialconstriction and
oedema of the broncho mucosa.Dilatation of the
bronchial blood vessels and increased viscid
bronchial secretion.These changes manifest as
wheezes,dyspnea,chest tightness,cough and
hypoxia in severe cases.
TYPES OF BRONCHIAL ASTHMA
• ANTIGENIC:antigen-antibody interaction on
the surface of the mast cell.It occurs due to
exposure to allergins(dust,pollen,animal
hair,certain food or drug e.g. penicillin
• NON-ANTIGENIC: is related to the specific
stimuli which may be chest infection,exposure
to cold hair,exercise,emotions or drug induced
e.g aspirin,morphine.
ANTI-ASTHMATIC DRUGS
• Asthmatic attack consists of 2 phases:
immediate(bronchospasm) and late
phase(bronchospasm and inflamation)
• BRONCHODILATORS: B adrenoceptor agonists,
methy-xanthines,muscarinic
antagonists,leucotrine receptor blockers
• B-ADRENOCEPTOR AGONISTS: b agonists
stimulate b receptors which leads to
brochodilatation and inhibit the release of mast
cell mediators.
B-AGONISTS
• SELECTIVE: salbutamol,terbutaline.They are
drugs of choice in asthma as they are short
acting,given by mouth,injection or sublingual.
• NON SELECTIVE:epinephrine,ephedrine
• ADVERSE EFFECTS: Tremor of skeletal
muscle,tachycardia,hypokalaemia,consitipatio
n,anxiety and restlessness.
METHYL XANTHINES
• Methyl xanthines are natural alkaloids of plant
origin found in caffeine,theophylline which are
present in coffee,tea,cocoa and cola.
• DRUGS:theophylline,aminophyline
• CLINICAL USES:bronchial asthma,obstructive lung
disease,left ventricular failure and pulmonary
oedema.CHF
• ADVERSE EFFECTS;narrow safety
margin,palpitation,diarrhoe,hypotension,dysarrh
ythmias,cardiac arrest,convulsions,cns
stimulation,insomia,proctitis and headache.
DRUG INTERACTIONS OF
THEOPHYLLINE
• Chloramphenicol increases plasma
concertration.Phenorbital reduces plama
levels.Synergistic effect on the heart with bagonists(e.g epinephrine)
• Precautions when administering theophylline:
monitor plasma levels(narrow safety
window)avoid use of non selective b-agonists to
avoid effects on the heart. Dose should reduced
in kidney,liver disease and old people. Dose
should be increased in smokers.
CONTRAINDICATIONS(THEOPHYLLINE)
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Caffeine in hypertensives
Cardiac dysrrthymias
Peptic ulcer
Epilepsy or convulsions
ANTIMUSCARINIC DRUGS
• Ias pratropium bromide: is a substitute for
atropin.It has the disadvantage developing
resistance and has delayed on set of action.
• ANTI-INFLAMMATORY
DRUGS:Glucocorticoids(anti-inflammatory
effect,immunosuppressive effects).Given by
inhhalation(beclomethasone)iv(hydrocortison
e)Oral(prednisolone)
ADVERSE EFFECTS(GLUCOCORTICOIDS)
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Cushing syndrome
Diabetes
Glaucoma
Peptic ulcer
Growth retardation in children
Candidiasis
Weight gain ,hypertension ,liability to
infection, delay healing of wounds.
PRECAUTIONS
• Taper dosage to avoid adrenal insuffiency
• To prevent candidiasis the patient should
gargle water and spit after each inhaled
steroid.
EXPECTORANTS AND ANTITUSSIVES
• EXPECTORANTS: Expectorants are a type of
cough medicine that help loosen mucus in
your lungs, making your cough more effective.
When your cough is more effective, it is also
more productive, meaning it becomes easier
to cough up mucus and its associated bacteria.
Clearing your lungs of mucus and bacteria can
help prevent certain illnesses such as
pneumonia.
EXPECTORANT CONT”D
‘Expectorant’ is derived from the Latin word expectorate
means drive from the chest. Expectorants are drugs used in
removing the mucous and other waste materials from the
respiratory tract. They stop the production and
accumulation of mucous in the respiratory tract causing
irritation and difficulty in breathing. Expectorants help in
diluting the mucous and lubricate the passage so that it
flows out easily.
• Examples include benylin(wet) mucolyn,koflyn and cadifen
in common pharmaceutical practice in Zambia.
Ephedrine
Ephedrine is used in cough medicine, such as Mollipect, in some countries
EXPECTORANTS CONT”D
• Dextromethorphan (DXM) may be modestly
effective in decreasing cough in adults with
viral upper respiratory infections. In children
however it has not been found to be effective.
Ephedrine is used in cough medicine, such as
Day relief and Night relief but its abuse has led
it to being controlled.
ANTI-TUSSIVES
• These are agents that specifically inhibit or
suppress the act of coughing. They should not be
used to suppress productive cough but used in
dry cough. They include dextromethorphan and
codeine. Codeine acts via opiod receptors. This
leads to suppression of the cough centre in the
medullaCodeine Codeine was once viewed as the
gold standard in cough suppressants. Some
recent placebo-controlled trials have found
however that it may be no better than placebo
for some etiologies including acute cough in
children.It is thus not recommended for children.
DECONGESTANTS
• Decongestants reduce nasal congestion and other
allergy symptoms by constricting the blood vessels and
decreasing the amount of fluid that leaks out into the
lining of the nose. Oral nasal decongestants come in
many forms, such as pills, tablets, liquids, or nasal
sprays.
• Commonly used decongestants include
pseudoephedrine and phenylephrine. These
decongestants work in the same way to reduce
swelling and congestion. These agents may be found
alone or more frequently in combination with other
medications such as antihistamines
SIDE EFFECTS OF DECONGESTANTS
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Common Side Effects of Decongestants Include :
Dry mouth or throat
Heart racing
Insomnia - You might not be able to fall asleep if taken
late in the day
Anxiety
Hyperactivity in children
In active asthma, decongestants can make secretions in
the lungs harder to clear
Difficulty in urinating, especially in men over 50 years
old
INDICATIONS
• Decongestants are helpful for the following
symptoms:
• Post nasal drip
• Nasal congestion
• Some coughs
• Sinus problems
• Some headaches especially from sinus
problems
CONTRAINDICATIONS(DECONGESTANT
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Who should not use decongestants?
People with:
Kidney disease
Diabetes
Glaucoma
High blood pressure
Heart disease
Pregnant women or those who are trying to get
pregnant
• Women who are breastfeeding
• Men with prostate problems
OXYGEN
• In medicine, mechanical ventilation is a method to
mechanically assist or replace spontaneous breathing. This
may involve a machine called a ventilator or the breathing
may be assisted by a physician, respiratory therapist or
other suitable person compressing a bag or set of bellows.
Traditionally divided into negative-pressure ventilation,
where air is essentially sucked into the lungs, or positive
pressure ventilation, where air (or another gas mix) is
pushed into the trachea. There are two main divisions of
mechanical ventilation: invasive ventilation and noninvasive ventilation.[1] There are two main modes of
mechanical ventilation within the two divisions: positive
pressure ventilation and negative pressure ventilation.
OXYGEN CONT”D
• Complications
• Mechanical ventilation is often a life-saving intervention, but carries
many potential complications including pneumothorax, airway
injury, alveolar damage, and ventilator-associated pneumonia.[5]
• In many healthcare systems prolonged ventilation as part of
intensive care is a limited resource (in that there are only so many
patients that can receive care at any given moment). It is used to
support a single failing organ system (the lungs) and cannot reverse
any underlying disease process (such as terminal cancer). For this
reason there can be (occasionally difficult) decisions to be made
about whether it is suitable to commence someone on mechanical
ventilation. Equally many ethical issues surround the decision to
discontinue mechanical ventilation.[6]
OXYGEN CONT”D
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Application and duration
It can be used as a short term measure, for example during an operation or critical
illness (often in the setting of an intensive care unit). It may be used at home or in
a nursing or rehabilitation institution if patients have chronic illnesses that require
long-term ventilatory assistance. Owing] to the anatomy of the human pharynx,
larynx, and esophagus and the circumstances for which ventilation is required then
additional measures are often required to secure the airway during positive
pressure ventilation to allow unimpeded passage of air into the trachea and avoid
air passing into the esophagus and stomach. Commonly this is by insertion of a
tube into the trachea which provides a clear route for the air. This can be either an
endotracheal tube, inserted through the natural openings of mouth or nose or a
tracheostomy inserted through an artificial opening in the neck. In other
circumstances simple airway maneuvres, an oropharyngeal airway or laryngeal
mask airway may be employed. If the patient is able to protect their own airway
and non-invasive ventilation or negative-pressure ventilation is used then a airway
adjunct may not be needed
OXYGEN CONT”D
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Common medical indications for use include:
Acute lung injury (including ARDS, trauma)
Apnea with respiratory arrest, including cases from intoxication
Chronic obstructive pulmonary disease (COPD)
Acute respiratory acidosis with partial pressure of carbon dioxide (pCO2) >
50 mmHg and pH < 7.25, which may be due to paralysis of the diaphragm
due to Guillain-Barré syndrome, Myasthenia Gravis, spinal cord injury, or
the effect of anaesthetic and muscle relaxant drugs
Increased work of breathing as evidenced by significant tachypnea,
retractions, and other physical signs of respiratory distress
Hypoxemia with arterial partial pressure of oxygen (PaO2) < 55 mm Hg
with supplemental fraction of inspired oxygen (FiO2) = 1.0
Hypotension including sepsis, shock, congestive heart failure
Neurological diseases such as Muscular Dystrophy and Amyotrophic
Lateral Sclerosis
OXYGEN CONT”D
• CONCLUSION:Oxygen: The odorless gas that is present
in the air and necessary to maintain life. Oxygen may
be given in a medical setting, either to reduce the
volume of other gases in the blood or as a vehicle for
delivering anesthetics in gas form. It can be delivered
via nasal tubes, an oxygen mask, or an oxygen tent.
Patients with lung disease or damage may need to use
portable oxygen devices on a temporary or permanent
basis.
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