Oral Cough and Cold Medicines

Common Cold

Common cold (cold) is a mild viral infection of the upper respiratory tract which is usually self-limiting. Symptoms associated with the common cold include nasal congestion, runny nose, cough (both phlegmy cough and dry cough), sore throat and sneezing. Sometimes, you may also feel tired, have headache or low-grade fever.

There are more than 200 viruses that can cause a cold and most people recover from a cold within a week or two. Medical advice should be sought as soon as possible if symptoms persist for more than 14 days or other symptoms develop (e.g. blood-stained phlegm, breathing difficulties, high fever (note that this is common in young children).

Treatment

Since the common cold is a viral infection, antibiotics will not work. The mainstay of treatment is to relieve the associated symptoms. Drinking plenty of fluid, taking more rest and taking drugs that alleviate symptoms could help you feel better.

1. Analgesics and anti-pyretics

Paracetamol, aspirin and ibuprofen are effective analgesics which can also reduce fever. Among the three drugs, paracetamol, sold as branded products or under the generic name paracetamol, is the most commonly used analgesic and antipyretic drug in Hong Kong. These 3 drugs should be used with caution in patients with liver impairment. Paracetamol can cause serious liver damage which can be fatal if too much of the drug is taken. Although liver damage can also occur with the use of aspirin or ibuprofen, it is of rare occurrence. Both aspirin and ibuprofen can cause irritation to the gastric mucosa and stomach upset. Furthermore, aspirin is generally not recommended for use in children for the treatment of colds because of the risk of Reye’s syndrome, a disorder characterized by acute encephalopathy and fatty degeneration of the liver. In fact, Reye's syndrome occurs almost exclusively in young children and several studies have found an association between Reye’s syndrome and aspirin consumption. Aspirin is not recommended in children under 16 years of age in Hong Kong unless otherwise prescribed by a doctor.

2. Decongestants

Sympathomimetics are widely used as nasal decongestants to clear stuffy nose in patients with colds. They cause vasoconstriction, leading to reduction in the swelling of the nasal mucosa and thus easing breathing and nasal stuffiness. Examples of oral decongestants include pseudoephedrine, ephedrine and phenylephrine. Oral decongestants can cause a rise in blood pressure, heart rate and increased alertness which may lead to difficulty in sleeping if taken during the latter part of the day. Medical advice should be sought in patients with certain medical conditions including high blood pressure and glaucoma before using decongestants because special precautions may be needed.

3. Cough medicines

Cough is your body’s natural protective response to clear mucus or other irritants in your throat and airways. Cough medicines commonly used in the relief of a cold can be categorized into three types, i.e. cough suppressants (antitussives), expectorants and mucolytics.

Treatment of non-productive cough (i.e. Cough without phlegm or dry cough)

• Cough Suppressants^

  Most cough suppressants suppress the cough reflex by a direct effect on the cough centre in the central nervous system. Examples of cough suppressants^ include codeine* and dextromethorphan. Codeine* is effective but it can cause constipation, drowsiness and dependence. Further, codeine* is contraindicated for all children younger than 12 years of age. The use of codeine* in adolescents 12 to 18 years of age who have other risk factors that may increase their sensitivity to the respiratory depressant effects of codeine* should also be avoided unless the benefits outweigh the risks. Risk factors include conditions associated with hypoventilation, such as postoperative status, obstructive sleep apnea, obesity, severe pulmonary disease, neuromuscular disease, and concomitant use of other medications that cause respiratory depression. Dextromethorphan tends to cause fewer side effects than codeine* but it still has the potential to cause drowsiness or dependence. Patients should not drive or operate machinery if they feel drowsy or that their mental alertness is impaired. Many cough suppressants contain demulcents as additives, which form a protective coating over the pharynx to relieve the irritation. Commonly used demulcents include honey, sucrose syrups, glycerol and liquorice.

Treatment of productive cough (i.e. Phlegmy cough)

• (i) Expectorants

  Expectorants are thought to work by increasing the volume of secretions in the respiratory tract which in turn, makes it easier to expel phlegm from the airways. Commonly used expectorants are ammonium salts, guaifenesin, ipecacuanha, senega and sodium citrate. Many traditional expectorants, including ipecacuanha, squill and ammonium chloride, also have emetic actions which cause a reflex irritant effect on the gastric mucosa and ease the clearance of tenacious sputum. Because of the way many of the expectorants work, gastrointestinal upset is common, although this may be rare for guaifenesin at doses normally used.

• (ii) Mucolytics

  Mucolytics act by decreasing the viscosity of mucus and thus facilitating its removal from the respiratory tract. Commonly used mucolytics include bromhexine, ambroxol, acetylcysteine and carbocisteine.

4. Antihistamines

Sedating antihistamines may be used as cough suppressants, classic example being diphenhydramine or promethazine. Their cough suppressant effect may come from their sedating effect. In addition, sedating antihistamines also reduce runny nose and sneezing. Therefore, they may be used in night time coughs, particularly those caused by post-nasal drip or associated with allergic rhinitis. Compounded cough and cold preparations often contain antihistamines such as chlorphenamine and brompheniramine. Non-sedating antihistamines, due to their lack of antimuscarinic effect, are relatively ineffective in relieving runny nose that are not of allergic nature.

Patients should not drive or operate machinery if they feel drowsy after taking antihistamines. Although the sedative effect may be less frequent with the use of non-sedating antihistamines, patients should be wary and take caution if performing tasks that require mental alertness such as driving. Driving or operating machinery should be avoided if you feel drowsy after taking antihistamines. Antihistamines should not be used in treating phlegmy coughs as they reduce bronchial secretions, leading to the production of more viscous mucus which becomes more difficult to remove.

Reduce the Side Effects of Oral Cough and Cold Medicines

The risk of side effects and their severity depend on the type, dosage and duration of medicine you take. For medicines that can cause irritation to the stomach such as ibuprofen, aspirin and expectorants, taking the medicine after food may help reducing the risk of gastrointestinal upsets. For medicines that increase mental alertness such as those of oral sympathomimetic decongestants, avoid taking these medicines in the evening may help to avoid difficulty in sleeping. Drinking plenty of water when taking codeine* will help to prevent constipation. In order to avoid the sedating effects of some antihistamines in daytime, you may take these medicines before going to bed.

General advice on taking Cough and Cold medicines

• Cough and cold medicines are not indicated for children under 6 years old. If your young child is suffering from symptoms of cough and cold, you should consult your doctor for the most appropriate treatment.

• Codeine* is contraindicated for all children younger than 12 years of age. Avoid the use of codeine* in adolescents 12 to 18 years of age who have other risk factors that may increase their sensitivity to the respiratory depressant effects of codeine* unless the benefits outweigh the risks. Risk factors include conditions associated with hypoventilation, such as postoperative status, obstructive sleep apnea, obesity, severe pulmonary disease, neuromuscular disease, and concomitant use of other medications that cause respiratory depression.

  
  

• Be familiar with the name and dosage of the drugs you are taking. Be cautious about their possible side effects. Many cough and cold medicines contain a number of ingredients and you should read the product labels carefully or consult your doctor or pharmacist to understand these products’ active ingredients and the possible drug interactions with other medicine you are taking. Avoid taking drugs which contain same type of active ingredients to prevent overdose or duplication of medicinal effects.

  
  

• Many cough and cold medicines may cause drowsiness or affect your mental alertness. Do not drive or operate machinery if you are taking these medicines. Always seek your doctor or pharmacist’s advice if you need to drive or operate machinery whilst taking cough and cold medicines.

  
  

• Do not drink alcohol when taking cough and cold medicines as it will increase the risk and severity of side effects of your medicines.

  
  

• Some cough and cold medicines such as pseudoephedrine, phenylephrine or ibuprofen may cause increase in blood pressure. You should seek your doctor or pharmacist’s advice before taking these medications.
  
  

• Take the drugs according to the labelled dosage instructions or as instructed by your doctor or pharmacist in order to reduce the risk of side effects.

  
  

• As some of these medicines contain caffeine, you should avoid drinking too many drinks that also contain caffeine, e.g. tea, coffee, cola, while taking these medicines.

  
  

• Take your medicines at the same fixed time every day as far as possible. If you miss a dose, take it as soon as possible or skip the missed dose and take the next dose as directed. Do not take double doses.

  
  

• Seek advice from a doctor if your symptoms worsen or you have any concerns about the medicines you are taking.

  
  

• Breastfeeding mother should seek medical advices before taking any cough medicines. For medicines containing codeine*, because of the potential for serious adverse reactions, including excess sedation, respiratory depression, and death in a breastfed infant, breastfeeding is not recommended during treatment with codeine*.

Communication with your doctor or pharmacist

• Cough and cold medicines, particularly when used in children, should preferably be used under the supervision of a pharmacist or a doctor.
  
  

• It is always prudent to seek your doctor or pharmacist’s advice on the best treatment option. Different type of cough and cold medicines may have different action and side effect profiles; your doctor or pharmacist will recommend the most appropriate drugs for you after considering your condition.
  

• Tell your doctor or pharmacist your medical history and the drugs you are also taking because cough and cold medicines may interact with other drugs and some diseases such as high blood pressure, liver or renal impairment may warrant special precautions.

  
  
  

• Inform your doctor or pharmacist if you are pregnant as some medicines may be best avoided during pregnancy, e.g. pseudoephedrine.
  
  

• Inform your doctor or pharmacist if you are breastfeeding as some types of cough and cold medicines are distributed into breast milk. For medicines containing codeine*, because of the potential for serious adverse reactions, including excess sedation, respiratory depression, and death in a breastfed infant, breastfeeding is not recommended during treatment with codeine*.
  
  

• Seek advice from your doctor or pharmacist as soon as possible if you experience any symptoms or side effects suspected to be related to your cough and cold medicines in order to review your medications.