Lecture 7: OTC Cough and Cold Flashcards
What do Pharmacological mechanisms of actions fundamentally begin with?
A drug receptor interaction
What four types of ingredients do commonly available cough and cold medications contain?
- Decongestants
- Cough suppressants
- Expectorants
- Anti-pyretics
What are OTC cough and cold medications used to treat?
Symptoms of upper respiratory infections (runny nose, congestion, cough, fever)
What is the purpose of the coughing reflex?
To clear the breathing passage of irritants, microbes, fluids and mucus
What is the function of the mucus in the upper respiratory tract?
The mucus is protective. It provides a barrier between the lumen of the airway and the epithelium
Why is mucus upregulated during infection?
To prevent penetration of those microbes and to provide substance to clear garbage out of the lungs and airways
Why would it be bad to suppress cough during bacterial infections?
Because the cough is used to get that bacteria out
What happens when you cough with viral infections?
You end up aerosolizing the particles because they’re so small
What is the coughing reflex initiated by?
The stimulation of sensory nerves innervating the throat and lungs
Which receptors in the throat detect irritation?
P2X3 and TRPV1
Where do the sensory neurons in the throat that detect irritation send their information?
To the cough center in the medulla oblongata
What happens after irritation is sent to the cough center in the medulla?
Efferent nerves via parasympathetic and motor nerves stimulate the diaphragm, intercoast muscles and lung to initiate a cough
What is the main nerve that stimulates the cough reflex?
CNX the vagus nerve
What are Anti-tussives?
OTC drugs that inhibit the cough reflex
How do most anti-tussives work?
By inhibiting neurons in the medulla oblongata
What are the three approved anti-tussives?
- Dextromethorphan
- Diphenhydramine
- Codeine
What is Codeine in terms of receptors?
A mu opioid receptor agonist
Where are Mu opioid receptors located?
In the medulla oblongata (cough center) and peripheral nerves innervating the respiratory tract
What is the most abundant opioid receptor in the CNS?
Mu
What is meant by codeine is a mu opioid receptor agonist?
Codeine activates opioid receptors
What kind of receptors are Opioid receptors?
They are inhibitory G-protein coupled receptors (GPCRs)
What happens when opioid receptors are activated by Codeine?
They inhibit calcium channels, activate K+ channels and inhibits adenylate cyclase which inactivate neurons and reduces neurotransmitter release in the cough center of the medulla
Which part of the CNS does Codeine act on?
The cough center of the medulla
Why are antitussives that contain codeine not recommend for those under 18?
Because they have undesirable effects like addiction and overdose. An can inhibit other brain areas like breathing area
