Cetirizine is second generation antihistamine and a selective H1-receptor. In addition, the hydrochloride salt of Cetirizine is a white powder administered orally. So, Cetirizine dihydrochloride is an antiallergic medication.

Chemistry of Cetirizine Dihydrochloride

Chemical Formula: C21H25ClN2O3. 2(HCl)

Molecular Mass: 461.81

Physical Properties: White crystalline powder
Solubility: Soluble in water& Methanol, practically insoluble in acetone and dichloromethane.

Pharmacokinetics of Cetirizine Dihydrochloride

After the oral administration of 10 mg dose of Cetirizine, peak blood levels of the order of 0.3 micrograms/ml are reached between 30 and 60 minutes. Its terminal half-life is about ten hours in adults and about 6 hours in children aged between 6 and 12 but the children aged between 2 and 6; the terminal half-life is about 5 hours.

Pharmacodynamics of Cetirizine Dihydrochloride

Cetirizine is a selective H1 antagonist with insignificant effects on other receptors and so is virtually free from anti-cholinergic and anti-serotonin effects. However, it inhibits the histamine-mediated early phase of the allergic-reaction and also decreases the migration of certain inflammatory cells and the discharge of certain mediators associated with the late allergic response.

Medical uses of Cetirizine Dihydrochloride

Cetirizine Dihydrochloride has following medical use:

  • To relieve the symptoms related with hay fever (e.g. rhinitis, conjunctivitis, itching of the eyes, rhinorrhoea)
  • To check motion sickness and other causes of nausea
  • During emergency treatment of severe allergic reactions
  • To reduce the severity of the rash and itching
  • Side effects of Cetirizine Dihydrochloride

    Though, cetirizine dihydrochloride is well tolerated; however, in some incidence, it has following side effects:

  • Sedation
  • Headache
  • Dry mouth
  • Gastrointestinal disturbances
  • Overdose of Cetirizine Dihydrochloride

    There are following symptoms of Cetirizine Dihydrochloride overdose:

  • Extreme sleepiness (generally in adults)
  • Restlessness & Irritability (generally in children)
  • Confusion
  • Headache
  • Mydriasis
  • Malaise
  • Malaise
  • Fatigue
  • Dizziness
  • Diarrhoea
  • Cautions of Cetirizine Dihydrochloride

    Simultaneous use of Cetirizine along with alcohol or other CNS depressants should be avoided because it may cause additional reductions in alertness and additional impairment of CNS performance.