Cough and the Common Cold Flashcards
What is the physiological purpose of a cough?
- helps to clear excessive secretions and foreign material from the airways
What are the 3 main types of coughs and how long do they last?
- Acute: usually lasts < 3 weeks
- Subacute: may last more 3-8 weeks
- Chronic: last > 8 weeks
Describe a productive cough
- mucous production (chest) - may feel full or congested
- may be associated with underlying inflammatory process (infectious) - therefore we don’t want to stop this type
- secretions may vary- may be clear or purulent
Describe a non-productive cough
- stimulated by a mechanical irritant or other type or irritant (irritation of the vagal nerve)
- feeling of tightness or wheezing due to congestion of the bronchial airways (no mucous production)
- often described as a “dry, hacking” cough
What are some of the most common causes of cough?
- common cold
- acute bacterial sinusitis/pneumonia
- exacerbation of COPD/asthma
- allergic rhinitis
- CHF
- GERD
- lung cancer or smokers cough
- ACE inhibitors
What are the red flags for cough?
- cough of over 3 weeks
- cough over 7 days that is unresponsive to self treatment
- cough with thick yellow sputum or green phlegm
- fever over 40.5 degrees or fever over 72 hours
- drenching night sweats
- sever headache/ prolonged nasal congestion
- blue lips, tongue or face
- difficulty breathing after exposure to smoke, flames, fumes or an allergen
- acute confusion
- cough having blood
- history of symptoms suggestive of chronic underlying airway disease associated with a cough (COPD, ex)
- difficulty breathing, chest pain, committing or choking
- suspected drug induced cough
- symptoms associated with croup or ear infections
What are the treatment goals when treating a cough?
- reduce the number and severity of cough episodes
- prevent complications
- treat underlying cause when possible
What are some of the non-pharms for treating a cough?
- increasing too humidity to soothe irritated airways (humidifier)
- warm mist humidifier and cool mist humidifier are equally effective– prefer cool mist humidifier
- vaporizers are humidifiers used with volatile inhalants such as camphor or menthol to produce a medicated vapour
- throat lozenges to soothe the throat and decrease the cough (glycerol/honey)
What are the 3 medications that are cough suppressants?
- codeine
- DM
- antihistamine
What are the 3 topical antitussives?
- camphor
- menthol
- eucalyptus
Dextromethorphan is indicated for the suppression of a _____ cough
non-productive
Dextromethorphan is a non-opioid analogue of ____. No analgesic, sedative, or respiratory depressant properties
codeine
What is the MOA of DM?
- increases the cough threshold by acting centrally in the medulla
What is the adult dose of DM?
po 10-20 mg Q4H or 30 mg Q6-8H (max 120 mg/day)
DM may be used in children over ______
6 y/o
What is the onset of action of DM?
15-30 minutes
What are the most common SE of dextromethorphan?
- generally well tolerated, occasional drowsiness, nausea, vomiting, or stomach discomfort
What are the drug interactions that are most common with DM?
- MAOI/SSRI: risk of serotonin syndrome
- CYP 2D6 inhibitors: inhibit metabolism of DM leading to increased DM levels
- polymorphic metabolizers: poor metabolizers will have longer half-lives
Is DM okay to take in pregnancy?
- yes, it is considered are in pregnancy for short term use - avoid preparations containing alcohol
Explain DM abuse
- at large doses, DM and its metabolite (dextrophan) causes dissociative effects
- adrenergic effects (such as hypertension and diaphoresis) can occur due to dose related inhibition of catecholamine reuptake
- serotonergic effects can result from agonist effects of serotonin receptors
- toxicity effects: restlessness, euphoria, hallucinations, visual and auditory disturbances, delayed reaction times, mania, panic, delusions, ataxia, partial and complete dissociation
The efficacy of DM is _____
limited
What is the use of codeine for?
- indicated for the suppression of non-productive coughs
What is the MOA of codeine?
- increases cough threshold by acting centrally on the medulla
What is the adult dose of codeine?
- 10-20 mg/dose Q4-6h (max 120 mg/day)
What is the onset of action of codeine?
1-2 hours
What are the side effects associated with codeine?
sedation, dizziness, nausea, vomiting, constipation
What are the drug interactions associated with codeine?
with other CNS depressants
What is the use of codeine in pregnancy and lactation?
pregnancy: can use short term
lactation: avoid use in breastfeeding
Codeine has questionable efficacy for treatment of an _____ cough, but has been found t suppress a ____ cough
acute
chronic
Codeine products are nationally schedule ___, but there are schedule ___ as well
2
1
What would you recommend first - DM or codeine? Why?
DM- less side effects with a bit more efficacy. Only prescribe codeine if the patient needs to sleep and has not been sleeping because of the cough
What is the interaction between codeine and asthma?
Asthma: use cautiously - can suppress coughs related to asthma (one of the first signs of an asthma exacerbation is a cough)
What is the interaction between codeine and diabetes?
want to choose a sugar free, alcohol free option, but other than this it is fine to use
What is the interaction between codeine and hypertension/CHF?
- need to caution in CHF, need to rule out the cough is not caused by hearty failure
- coughs do not just happen on their own (if it was viral in nature, then the person will have has a sore throat and runny nose) - a lack of these symptoms is indicative of the person potentially having heart failure
What is the interaction between codeine and immunosuppression?
- caution, need to rule out cough not due to condition
What is the interaction between codeine and breastfeeding?
- in general want to avoid
What is an expectorant used for and what is the main expectorant used?
- used for productive coughs
- guaifenesin
What is the action of guaifenesin?
- reported to reduce sputum viscosity and facilitate mucous removal from the upper RT (does NOT suppress the cough however)
- considered sade and effective- lack of evidence to truly support efficacy
- increasing hydration with oral liquids, humidifying air may prove more effective (or just as effective)
- considered safe in pregnancy
What is the dosing of guaifenesin?
200-400 mg q4h (max 2.4g/day)
What are the SE associated with guaifenesin?
SE are rare- typically cause, drowsiness, headache, and rash have been reported at high doses
What is the interaction between guaifenesin and asthma/COPD?
- okay to give to people with asthma, but not generally recommended in COPD due to the need to refer if a person with COPD has an excessive amount of congestion
What is the interaction between diabetes and guaifenesin?
- an recommend it in diabetes
What is the effectiveness of a combination therapy of guaifenesin and DM?
- there is none! The retention of mucous with a productive cough can be counterproductive and can worsen the condition
What is a common cold
- an acute, viral and self-limiting infection
- infection of the mucous membrane of the URT
- most frequently managed illness
What virus most likely causes the common cold?
- rhinovirus
Explain the transmission of the common cold?
- spread via small and large particle aerosol
- incubation period is 1-3 days
- virus can be transmitted before symptoms occur
What different surfaces can cold viruses be transmitted on?
- contaminate skin surface (shake hands with an infected person) or environmental surface
- aerosols in the air
- direct hit by large particles (from an infected person)
- inadvertently deposits the virus into his/her nose, eye, mouth
What risk factors put a person at a higher risk of a cold?
- smoking (cilia is damaged)
- allergic disorders affecting the nose or the pharynx
- increased population density
- a sedentary lifestyle
- chronic (duration 1 month or more) psychological stress
Describe the pathogenesis of the common cold
- virus binds to specific receptors on the nasal epithelial cells
- viral replication, infected cells rupture
- triggering of the host’s defence mechanism
- release of inflammatory mediators (PG, LK, kinins)
- vasodilation and increase vascular permeability in the sinus tissue
- increase mucous production
- accumulation of extracellular fluid in the mucous membrane (congestion)
- cholinergic stimulation
- nasal sneezing, mucous gland secretion
What antihistamine can be used to treat colds?
- 1st generation antihistamines - used for their anticholinergic and drying effects
What are the signs prevalent in the early stages of the common cold?
- dry, unproductive cough
- due to irritation of the vagal nerve by inflammatory mediators approx. 2 days
What are the signs prevalent in the later stages of the common cold?
- productive cough due to the body clearing mucous from lungs and sinuses (phlegm is clear or whitish in colour, thick/thin consistency)
- post nasal drip syndrome
What are the most prevalent red flags for the common cold?
- fever over 38.5 degrees for more than 72 hours
- chest pain, difficulty breathing, wheezing, stridor
- infection signs
- children under 6 y/o - cannot have cough and cold symptoms in this case
- children under 1 y/o in general with cold sx
- other respiratory or underlying conditions (chronic bronchitis/emphysema) or immunocompromised
- frail patients over 65
- severe throat pain
- prolonged nasal congestion with purulent discharge
- sever headache, neck pain
- signs of dehydration in an infant
What are the non-pharm approaches for treating the common cold?
- increase fluid intake
- avoid smoking
- proper hand-washing
- increase humidification
- salt water gargle
- bed rest
- normal saline or nasal breathing strips (congestion)
- cover mouth when coughing or sneezing
- local menthol on the chest
- hot fluids
What are sympathomimetics?
- alpha adrenergic agonist properties causes vasoconstriction of nasal blood vessels - decrease nasal congestion, increase nasal patency and drains nasal secretions
What are the drug-drug interactions associated with decongestants?
- MAOI’s, TCA’s, methyldopa, etc
Explain first generation antihistamines?
- symptoms of the common cold are not primarily histamine mediated
- it is thought that the anticholinergic effect of drying the nasal mucosa
- AH-decongestant combination: useful for patients with congestion, sneezing and runny nose
- convenient but does not allow for flexibility
- may be useful in the treatment for post-nasal drip related to the common cold
- short term use/sedation still is a concern- combining agents does not decrease the side effects of either agent
Can decongestants be used in a patient with high blood pressure?
- no, they can not be
What is saline nasal drops recommended for?
- recommended to loosen thick nasal mucus
What are topical antitussives?
- combination of menthol, camphor, and eucalyptus oil. Perception of improvement in cough and congestion, but evidence is lacking
What are local anesthetics used for in colds?
- available for temporary relief of sore throats. May be used every 2-4 hours. Some products contain local antiseptics - not effective in viral infections
What is the efficacy of vitamin C?
- no evidence that it can treat or prevent the common cold
What is the efficacy of zinc?
- no real effect/unacceptable metallic taste for most patients
What is the efficacy of ammonium salts?
- ammonium chloride used as an expectorant (Buckley’s)
What is the efficacy of echinacea?
- no conclusive evidence (safety vs efficacy. Proposed to help the immune system fight infection better/faster. Cl- immunocompromised
When is the ONLY time that cold fx will work?
- if you take one everyday for 4 months and you happen to get a cold, it will decrease the duration of the cold by up to 6 days. 4 months of treatment will prevent ONLY 1 COLD
How does North American Ginseng work?
- insufficient evidence that this works to reduce incidence or severity of the common cold (systematic review)
- some case reports that this works to reduce the duration by 6 days IF used for daily 4 months
- any studies ONLY looked at healthy adult individuals
- avoid if on anticoagulants, pregnant, impaired renal or liver, diabetes, insomnia, cancer and schizophrenia
What is the action of honey? What does it help suppress?
- potentially suppresses cough
- soothing effect
(SHOULD BE PASTEURIZED-risk of botulism and avoid in children under 1 year old)
What is the recommended dosing of honey?
0.5 tsp for children 2-5, 1 tsp for children aged 6-11 and 2tsp for children 12-18 and adults
What is the general rule of thumb over decongestant use?
- topical agents are generally preferred over oral
- re. systemic absorption in patients with chronic disease states
- ex. if a person has severe cardiac disease- then they should not use either oral or topical decongestants
In children with cough and cold symptoms likely du to a viral illness, what is the most effective course of treatment?
- increase fluid intake
- clear nasal passage
- use a nasal secretion bulb and nasal saline
- make sure there is adequate humidity
Explain how to use a rubber bulb?
- squeeze bulb syringe to expel air
- insert tip of the bulb 0.25 to 0.5 inches into the baby’s nostril pointing toward the side of the nose
- release bulb, holding in place to suction the mucous
- remove syringe and empty contents onto a tissue
- clean bulb syringe with soap and water (has to be used until the age of 4- children cannot blow their nose themselves)
Cough associated with post nasal drip can be treated with what?
- can be treated with a decongestant and antihistamine
1st generation as it is more effective for a runny nose and sneezing due to a cold
OTC treatment of colds should not exceed _____ days
7 (exception of topical decongestants 3-5 days)
