Diphenhydramine

Diphenhydramine is an antihistamine medication.

Pronunciation: DYE-fen-HYE-dra-meen

What are diphenhydramine’s uses?

In South Africa, diphenhydramine is primarily used as an aid to induce sleep and as a cough suppressant in cough mixtures. 

What dosage should you take?

The typical dose for adults to assist in falling asleep is 25 to 30mg at bedtime. For treatment of cough it is 15mg to 30mg up to three times daily. Dosages will vary depending on the condition being treated, the severity of the condition and the age of the patient.

Always check the correct dosages with your Clicks pharmacist.

What special precautions should you take?

  • Diphenhydramine may cause drowsiness or dizziness, so be advised to not drive or perform other potentially unsafe tasks (like operating heavy machinery) until you know it is safe to do so.
  • Be advised to inform your doctor if you’re pregnant or are planning to get pregnant.
  • Avoid alcohol as this may worsen the medication’s side effects of drowsiness and dizziness.
  • Do not give diphenhydramine to a child younger than 12 years of age. Always exercise extreme caution when giving medication for colds to children, always seek advice from your doctor or Clicks pharmacist first.
  • Avoid while breastfeeding, as diphenhydramine is passed into breast milk, and may harm a nursing baby.
  • Side effects may be more pronounced in the elderly.
  • Inform your doctor or Clicks pharmacist if you are taking potassium.
  • If prescribed for motion sickness, take medication 30 minutes before travelling.

Diphenhydramine should be avoided if you suffer from the following conditions:

Diphenhydramine should be used with caution if you suffer from the following conditions:

  • Liver impairment
  • Bowel obstructions
  • Colostomy or ileostomy (abdominal surgical procedures)
  • Heart disease
  • Low blood pressure (hypotension)
  • A thyroid disorder

What drug interactions could you experience?

To avoid adverse drug interactions, always inform your doctor or Clicks pharmacist what prescription and non-prescription medications, vitamins, nutritional supplements and herbal products you are taking or planning to take.

What are diphenhydramine’s side effects?

Side effects could include:

  • Sedation
  • Drowsiness
  • Dizziness
  • Coordination disturbances
  • Acid reflux
  • Sensitivity to the sun

This is not a complete list of side effects. It’s essential that you call your doctor should you notice any severe or odd side effects.

What are the overdose symptoms?

Call a doctor or an ambulance immediately if you suspect an overdose and notice the following symptoms:

  • Extreme sleepiness
  • Blurred vision
  • Large pupils
  • Dry mouth
  • Fever
  • Hallucinations
  • Shaking
  • Seizures
The accuracy of this information was checked and approved by Clicks' pharmacist Waheed Abdurahman in April 2015