Drugs used to treat asthma & drugs affecting the respiratory system (L12)

Question 1

regulation of respiration

Answer 1

spontaneous rhythmic discharge

voluntary control

autonomic regulation

Question 2

parasympathetic activation

Answer 2

bronchial and vascular smooth muscle and glands

M3 cholinergic receptors

stimulation results in bronchoconstriction and increased mucus secretions

Question 3

sympathetic activation

Answer 3

adrenergic regulation

circulating adrenaline from the adrenal medulla acts on B2 receptors on chronicle smooth muscle

smooth muscle relaxation and bronchodilation

Question 4

NANC innervation

Answer 4

nonadrenergic noncholinergic

inhibitory:
• NO on bronchial smith muscle
• smooth muscle relaxation and bronchodilation

excitatory:
• substance P, neurokinin A
• smooth muscle contraction and bronchoconstriction

Question 5

disorders of respiratory function

Answer 5

asthma

cough

Question 6

what is asthma?

Answer 6

recurrent reversible obstruction of the airways in response to stimuli which are not themselves noxious and do not cause the syndrome in non-asthmatics

Question 7

pathology of asthma

Answer 7

acute airway obstruction caused by contraction of the airway smooth muscle

mucus hyper secretion and thickening

airway inflammation

Question 8

symptoms of asthma

Answer 8

dyspnea

wheezing

coughing

Question 9

2 phases of asthma

Answer 9

immediate phase
• bronchoconstriction on exposure to stimuli

late/delayed phase
• inflammation/damage in response to inflammatory mediators

Question 10

immediate phase

Answer 10

bronchospasm

interaction with mast cells
• release of spasmogens - histamine and leuktreines
• bronchospasm
• release chemotaxis, LTB4 attraction of leukocytes

Question 11

late phase

Answer 11

inflammation and hypertension

influx of cytokines releases lymphocytes and eosinophils
• long lasting damage to epithelium of bronchial tissue
• hyperactivity of bronchial tissue

Question 12

what do asthma drugs do?

Answer 12

aim to prevent the release of bronchospasm from mast cells

Question 13

what are some bronchodilators?

Answer 13

beta2 agonists

muscarininc (M) antagonists

xanthines

Question 14

what do beta2 agonists do?

Answer 14

dilate bronchi

inhibits mediator released from mast cells

given by inhalation:
• short acting - salbutamol
• long lasting - salmeterol

side effects:
• tolerance
• tremor

Question 15

action of salbutamol/salmeterol on beta2 adrenoreceptors

Answer 15

1) salbutamol/salmeterol acts on the receptor
2) activates adenyl cyclase
3) increase cAMP
4) smooth muscle relaxation
5) bronchodilation
6) it them dissipates from receptor

Question 16

how is salmeterol different from salbutamol?

Answer 16

has a large lipophilic chain attached

when it dissociate it doesn’t go far as it is still attached to cell membrane

it doesn’t get metabolised as quickly as salbutamol which means they have different half lives

Question 17

what do muscarinic antagonists do?

Answer 17

dilate bronchi
• block M3 mediated bronchoconstriction

decrease mucus secretion

eg. ipratropium
• given by inhalation
• relatively non-selective but not well absorbed

Question 18

what do xanthines do?

Answer 18

bronchodilator
• block phosphodiesterase III and IV increasing cAMP leading to bronchodilation

anti-inflammatory properties

eg. theophylline
• well absorbed orally
• narrow therapeutic window

Question 19

drugs used to treat bronchospasm

Answer 19

chromolyn

beta2 agonist

M antagonist

xanthines

glucocorticoids

Question 20

what do glucocorticoids do?

Answer 20

effective in the treatment of the delayed phase

suppress the inflammatory response
• induces synthesis of lipocortin which inhibits phospholipase A2 so decreases production of inflammatory mediators

side effects:
• oral thrush
• cushings syndrome

Question 21

chromolyn

Answer 21

mast cell stabiliser

• prevents release of histamine and inflammatory mediators

Question 22

most recent drug used to treat asthma

Answer 22

cysteine-leukotriene (CysLT1) receptor antagonist

Question 23

cysteine-leukotriene (CysLT1) receptor antagonist

Answer 23

treats both phases

effective for mild-persistent asthma

non as effective as glucocorticoids - not as many side effects

Question 24

what is a cough?

Answer 24

reflex triggered by mechanical or chemical stimulation of the upper respiratory tract

serves to expel foreign bodies and unwanted material from the airways

Question 25

regulation of cough

Answer 25

sensor components

central components - cough centre in hypothalamus

intercostal and phrenic nerves regulating respiratory muscle

Question 26

drugs used in the reduction of sensory receptor sensitivity of cough

Answer 26

menthol vapour

eucalyptus oil

topical local anaesthetics - benzococaine and cocaine

Question 27

drugs that target the cough centre in the brain

Answer 27

regulated by opioid receptors

opiod receptor agonists

eg. codeine and dextromethophan