Pharmacotherapy/Treatment Of Cough And Common Cold

Cough is a symptom of a disease while common cold is a disease. Both are common and endemic around the world.

Cough and common cold

Cough

Cough is a reflex action that clears the throat. When mucus in the throat becomes excess or too thick or when there is presence of a foreign element, the body's natural defence is to get rid of it. It does this through coughing. It can be voluntary.

It begins with an initial gasp that draws air deep into the lungs. Next the glottis snapped, putting a lid over the trachea or windpipe. The chest case, abdomen and diaphragm contract forcefully creating a strong pressure on the lungs. Finally, the glottis swing open and air rushes out at the speed of sound.

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Cough is triggered by stimulation of two different classes of afferent neurons; myelinated rapidly adapting receptors and non myelinated C fibres with endings in the lungs.

Cough lasting less than three weeks is called acute cough. Cough that span across 3-8 weeks is sub acute but above that is chronic.

Symptoms

There are different types of cough. However, cough is a symptom on its own of an underlying condition. Other symptoms to look out for are;

1. Fever

2. Chest pain

3. Headache

4. Drowsiness

5. Confusion

Causes

There are many things that cause change in the viscosity of the mucus. Those that don't change the viscosity of the mucus are foreign elements that find their way into the throat triggering cough reflex.

Pharmacotherapy/Treatment Of Cough And Common Cold

If cough medicines do work, they are thought to work in different ways, depending on what the active ingredient is:

Antitussives are said to work by reducing the cough reflex. For example, dextromethorphan or pholcodine. Expectorants try to help loosen secretions, so you cough up the excessive mucus - for example, guaifenesin or ipecacuanha.

Antihistamines reduce histamine release. This reduces congestion and decreases the amount of secretions made by the lungs. Examples are brompheniramine, chlorphenamine, diphenhydramine, doxylamine, promethazine or triprolidine. Decongestants cause the blood vessels in the lungs and nose to narrow (constrict), and this reduces congestion. Examples are phenylephrine, pseudoephedrine, ephedrine, oxymetazoline or xylometazoline.

Acute Cough

Acute cough is normally caused by hay fever, lower respiratory tract infections like bronchitis and pneumonia. Less common cause of adult cough is tuberculosis, fungal infection and lung cancer. A common cause is breathing through the mouth. Some of these can proceed to chronic cough.

Chronic Cough

1. Post nasal drip (upper airway cough syndrome): the nose makes the air we breathe in warm, moist and free of dirt. This is achieved by the mucus that is warm, moist and sticky. An injury to the nose leads to mucus that is thin, watery and runny. It drips back into the throat triggering a cough. It tickles the nerves of nasopharynx. It is frequent at night.

Pharmacotherapy/Treatment

Nasal irrigation or steam use two to three times a day can help free up the nose. Antihistamine like chlorpheniramine and decongestant like guaifenesin are suitable products for post nasal drip cough. Antihistamine inhibits cough reflex while decongestant breaks up the phlegm.

Decongestants cause racing heart and souled up feeling but antihistamine are known for drowsy effect. Men with benign prostatic hyperplasia (BPH) will find it difficult to urinate due to decongestant while antihistamine triggers glaucoma.

2. Asthma: this is caused by irreversible narrowing of the bronchi. The air passes through with an extra force creating a noise like wheezing sound. However, not all asthmatic conditions get to that level. Some come with just a cough that does not respond to other treatments. The cough is dry, persistent and occurs mostly at night. It is caused by the person's trigger which is different for most asymptomatic patients.

It is difficult to differentiate athsmatic cough from others. When treatment of other coughs fails, asthmatic cough is suspected. Inhalation of methacholine, a drug that often triggers wheezing in asthma is used to diagnose it.

Pharmacotherapy/Treatment

The use of bronchodilator spray such as salbutamol and corticosteroids such as fluticatison, triamcilonin or budesonide is used to see if the patient responds.

3. Gastroesophageal reflux disease and other disease: this happens when stomach contents travel upstream making their way to the esophagus instead of down the intestine. The acid irritates the nerves of the esophagus. This led to a cough.

Diagnosis is the use of esophagus pH monitoring over a 24 hour period. A probe is swallowed that stays in the esophagus in 24 hours. Barium swallow x-ray and esophagoscopy  are cheaper and more convenient alternatives.

Coughs caused by heart failure are dry or produce thin frothy white sputum. Persistent when lying flat. Other symptoms are leg swelling, fatigue and exercise intolerance.

Pharmacotherapy/Treatment

Liquid antacid at bedtime is the best solution. Persistent cough may require an additional acid suppressant like omeprazole 20mg taken 30 minutes before food every 12 hours. Others are ranitidine, cimetidine, lansoprazole, etc.

Patients should not go to bed immediately after eating. Should sleep with a head well raised using a good pillow to prevent reflux. Products containing caffeine should be avoided. Eat a small bit of food under 24 hours and not a single food two times a day. Avoid ulcer triggers.

4. Chronic bronchitis and bronchiectasis: while bronchitis is the inflammation of the bronchial tubes causing excess mucus and airway narrowing, bronchiectasis on the other hand is when the inflammation leads to damage. Exposure to pollutants and other triggers over a long period of time such as tobacco smoking is the cause. Bronchitis and bronchiectasis can be caused by infection. They are called respiratory tract infections (RTI). The most common cause are viruses of common cold and flu.

Chronic obstructive pulmonary disease (COPD) is the umbrella name for these conditions. It comes with thick, dark mucus production with fatigue and shortness of breath.

Pharmacotherapy/Treatment

The use of corticosteroid inhaler and oral (prednisolone) products help resolve bronchial and bronchiectasis conditions. In some situations, an antibiotic can be used such as azithromycin. Bronchitis or bronchiectasis caused by viruses cannot be treated with antibiotics. Cough syrups, codeine and analgesic can be used.

5. Angiotensin converting enzyme inhibitors (ACEI): about 20 percent of people using ACEI experience mild to severe cough. The cough is dry and can begin in a week of starting the drug or even up to a year. It starts with a throat tickles that lingers and lingers.

Pharmacotherapy/Treatment

There is no treatment for it except changing to more recent angiotensin receptor blockers (ARB) like candesartan, losartan, etc.

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Types Of Cough

Wet cough (chesty cough): they are called productive coughs. Coughing action free up mucus known as phlegm. Mucus comes from the throat, nose, airway and lungs. Runny nose, post nasal drip are other symptoms that accompany it. They are caused by pneumonia, cold, flu and COPD (emphysema, acute and chronic bronchitis).

Pharmacotherapy/Treatment

Babies and toddlers can be given cool-mist humidifier and saline nasal drips. Honey helps children above a year. Adults do well with expectorants such as ammonia chloride, guaifenesin potassium iodide, etc.

Expectorants should not be given to babies and toddlers as there is no evidence of their benefit.

Dry cough: is a cough that does not come with mucus. It feels like a hacking cough. It is more difficult to manage. It is usually due to irritants or inflammation of the respiratory tract. Cold and flu are the most common causes. Others are laryngitis, sore throat, croup, tonsillitis, sinusitis, asthma, allergies, GERD, ACEI, human covid-19.

Pharmacotherapy/Treatment

The use of humidifiers in children is recommended. Antihistamine, drugs for asthma and antibiotics are recommended depending on the cause. The antihistamine is a cough suppressant. Codeine and pholcodine is use for dry cough but ban in Nigeria. Dextromethorphan is a drug for dry cough. Liquid antacids are used when it is caused by GERD.

Paroxysmal cough: comes with intermittent attacks with violent, uncontrollable coughing. It feels exhausting and painful. The most common cause is pertussis (whooping cough) caused by bacteria. In whooping cough, the air releases all the air they have caused the person to inhale violently leading to a whoop sound. Can be dangerous especially in children. There is an available vaccine. Other causes are asthma, COPD, pneumonia, tuberculosis and choking. Treatment is the use of antibiotics. Antibiotics include cephalosporins such as cefuroxime and cefixime, azithromycin, amoxicillin, etc.

Croup cough: is a situation whereby the upper airway is irritated and swollen. It affects children less than five years because they have narrow airways. It is characterized by a barking cough that sounds like a seal. Swelling in and around the voice box causes a raspy voice and squeaky breathing noises. Symptoms are struggling to breath, high pitch noise during inhalation and rapid breath. Children become pale or bluish.

Pharmacotherapy/Treatment

The use of a humidifier in children. Drugs include paracetamol, nebuliser or steroids. Home care includes breathing cool air in the house or outside, drinking plenty of fluids as well as a steam bath.

Medical Review

Before a medical doctor will decide on the best approach, they ask certain questions.

1. What triggers it when it happens?

2. Is it a dry cough or wet one?

3. How long have you been having it?

4. Are you vomiting?

5. How serious?

Diagnosis

Symptoms are used as diagnosis in most cases as laboratory diagnosis may not be needed. When the cause of the cough is difficult to diagnose using symptoms, a laboratory investigation is ordered.

Note: colour of sputum indicates infection of congestive heart failure (CHF) but this is not a confirmed scenario.

1. Chest x-ray

2. Blood and skin test

3. Mucus analysis

4. Echocardiogram

5. CT scan

6. Esophagus pH monitoring

7. Spirometer is a tube attached to a machine. Breathing in and out of the tube to check for airways obstruction.

Prevention

Prevention of cough depends on so many factors. For example, quitting smoking is a good step to avoid coughing. Dieting, avoiding triggers are Some other ways. Basically, it depends on the cause.

Common Cold

Common cold is an upper respiratory tract viral infection. It affects the nose and throat. There are over 200 species of viruses responsible for common cold. It is usually harmless and resolves on its own within a few days to 10 days. Prolong or increase duration of symptoms common among smokers. More common in children less than 6 months with increased risk. Produce between 6-10 yearly episodes in children and 2-3 yearly episodes in adult.

Symptoms

Symptoms usually appear about 1-3 days after exposure to infection. Symptoms between children and adults vary but have some similarities. They have runny or stuffy nose, sneezing, low grade fever, cough, congestion, discharge that is thick and yellow or green. Adults normally report loss of smell, sore throat, slight body aches or mild headache and malaise.

Cause

There are about 200 viruses responsible for the common cold. The most common is rhinovirus. Others are respiratory syncytial virus, human parainfluenza virus, adenovirus, human coronavirus, human metapneumonia, picornaviruses (99 serotype), influenza virus, and enterovirus.

Staying in a cold environment does not cause the common cold. Some theories have been put forward as to why staying in a cold environment can lead to the common cold. For example, the cold season makes people stay indoors. When families stay indoors, it is easy to transmit the virus among family members. Cold is also believed to decrease immune response due to changes in the respiratory tract. Low humidity (dry air) allows small viral droplets to disperse further and stay in the air for a longer increasing rate of transmission.

Risk Factors

Children below the age of 6 years are prone to common cold. Others are those with weakened immune systems, cold seasons, smoking and exposure to those with the infection.

Complications

Otitis media: the virus causing common cd enter the space between the eardrum. Signs are earache, green or yellow discharge from the nose and fever.

Acute sinusitis: infection and inflammation of the sinuses.

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Others are asthma, streptococcal pharyngitis, pneumonia, croup or bronchitis in children.

Diagnosis

1. Chest X-ray

2. Other test to rule out other conditions

Pharmacotherapy/Treatment

Analgesics such as paracetamol, ibuprofen, aspirin, etc. can be use. Aspirin should not be given to children, especially those recovering from chicken pox or flu-like symptoms because of Reye baby syndrome. Cough decongestant syrup is the option that is well accepted but still under debate. Side effects of cough decongestant include dizziness, dehydration, dry mouth, nausea and headache.

Home remedies include fluid replacement, rest, warm environment, gargle with warm salt water and saline nasal drop. Others are fruit high in fibre and flavonoids. Some suggest drinking warm foods like tea and pepper soup.

Vitamin C is claimed to boost immunity to fight common cold but no evidence to back this up. Zinc is another supplement that is touted to help with common cold but high doses cause loss of taste. Echinacea is a herbal supplement that is under investigation.

Prevention

Children can pick up the virus in crowded environments. Wash hands always as well as keep a safe distance from sufferers. Also, some advocate for the use of facemask especially for coronavirus. Adults should quit smoking.