16.1 Cough, Cold & Allergic Rhinitis

Cough and Cold: Drug or Honey First?

The common cold is viral and self-limiting; pharmacists counsel on supportive care and screen for conditions needing referral. Cough is classified as dry/non-productive (antitussive appropriate) or productive/chesty (expectorant or simply hydration).

• Antitussive — dextromethorphan: suppresses the cough reflex in the medulla. Used for dry, tickling cough that disturbs sleep. Avoid in children under 2 (and many regulators advise against OTC cough/cold preparations under 6 years).
• Expectorant — guaifenesin: reduces sputum viscosity so secretions clear more easily. For productive cough; encourage fluid intake alongside.
• Honey: evidence-supported cough soothe. Contraindicated in infants under 1 year because of infant botulism risk. Give 1–2 teaspoons at bedtime to children ≥1 year and adults.

Paediatric safety rule

Do not recommend OTC cough/cold combination products for children under 2 years. Codeine is contraindicated for cough/pain in children under 12 and is avoided in adolescents 12–18 who are obese or have conditions that increase codeine sensitivity. Dextromethorphan is also avoided in young children because of the misuse/sedation risk.

Decongestants: Pseudoephedrine Cautions

Pseudoephedrine is a sympathomimetic that constricts nasal vasculature, easing congestion. It also raises blood pressure and heart rate. Caution/avoid in:

Topical decongestants (xylometazoline, oxymetazoline) avoid systemic cardiovascular effects but must be limited to ≤5 days to prevent rhinitis medicamentosa (rebound congestion).

Allergic Rhinitis

Allergic rhinitis (hay fever) presents with sneezing, itchy nose/eyes, rhinorrhoea and nasal blockage. The pharmacist distinguishes intermittent vs persistent and mild vs moderate-severe (sleep disturbance, impairment of daily activities).

Stepwise approach:

1. Non-sedating oral antihistamine — first-line for mild intermittent disease. Cetirizine 10 mg once daily, loratadine 10 mg once daily, or fexofenadine 120–180 mg once daily. Onset within 1–3 hours; effective for sneeze/itch/rhinorrhoea, less so for congestion.
2. Intranasal corticosteroid — fluticasone or budesonide, one spray each nostril daily. The most effective single therapy for moderate-to-persistent rhinitis; onset over several hours to days, counsel on regular daily use (not PRN) and technique (aim away from septum to avoid epistaxis).
3. Sedating antihistamines (e.g. chlorphenamine 4 mg every 4–6 h) — useful at night if sleep disrupted, but cause marked drowsiness and impair driving/machinery the next morning. Warn the patient.
4. Intranasal sodium cromoglicate — mild disease, paediatric preference, slow onset.

Exam traps

• "Sedating antihistamines are better for daytime work" — false; they impair performance.
• Intranasal corticosteroids need regular daily use; ordering them "as needed" reduces efficacy.
• Topical decongestant beyond 5 days causes rebound congestion.

Referral red flags

Refer immediately if any of: stridor/breathing difficulty, high fever with rash, symptoms beyond 10 days or worsening after initial improvement (bacterial sinusitis suspicion), unilateral facial pain with purulent discharge, chest pain, or cough lasting >3 weeks.

Worked example — allergic rhinitis selection

A 30-year-old presents with sneezing, itchy eyes and nasal blockage every morning for the past 6 weeks, interfering with work. She takes the combined oral contraceptive pill and has no asthma. This is persistent moderate allergic rhinitis (symptoms >4 days/week and >4 consecutive weeks, with impairment). First-line is a non-sedating oral antihistamine (loratadine 10 mg daily) for immediate relief, plus an intranasal corticosteroid (fluticasone 50 µg, one spray each nostril once daily) because she has persistent blockage. Counsel her that the intranasal spray takes several days for full effect, to use it every day rather than only on bad days, to angle the nozzle away from the nasal septum, and to expect benefit within 1–2 weeks. If symptoms remain uncontrolled at 2–4 weeks, refer for prescription add-on therapy (e.g. intranasal antihistamine azelastine, or referral to exclude structural causes).

Worked example — decongestant caution

A 58-year-old man with hypertension (on amlodipine) and BPH asks for a decongestant for a heavy cold. Oral pseudoephedrine is inappropriate (hypertension, BPH with retention risk). Offer xylometazoline 0.1% nasal spray, one spray per nostril every 8–10 hours for a maximum of 5 days, plus saline nasal spray for ongoing moisture. Counsel on the rebound-congestion risk if he exceeds 5 days, and refer if facial pain or purulent discharge develops.

Antihistamine dosing table

Key exam traps

• "Topical decongestants are safe for long-term use" — false; limit to 5 days.
• "Sedating antihistamines are the first-line for daytime allergic rhinitis" — false; non-sedating agents are first-line.
• Codeine and dextromethorphan are not recommended in young children.
• Pseudoephedrine is still unsafe for 14 days after stopping an MAOI, not just while the patient is taking it.

Counselling checklist before selling a cough/cold product

1. Confirm age — refuse combination OTC cough/cold for <2 years; avoid codeine <12 years.
2. Check comorbidities — hypertension, heart disease, glaucoma, BPH, hyperthyroidism.
3. Screen current medicines — MAOIs, antihypertensives, SSRIs/SNRIs (dextromethorphan serotonergic risk at high dose), other sympathomimetics.
4. Pregnancy/breastfeeding — pseudoephedrine avoided (also theoretical uterine vasoconstriction); consider saline drops and honey (if ≥1 yr).
5. Set the treatment window — most colds resolve in 7–10 days; refer if worsening or not improving.