What is Astemizole

NOTE: This drug is discontinued in the US.

Astemizole is an oral H1-receptor antagonist that is similar in structure to terfenadine, another H1-receptor antagonist.

Both agents are also structurally related to haloperidol, a butyrophenone antipsychotic.

Interestingly, all three agents have been associated with torsades de pointes.

Unlike other H1-antagonists, therapeutic doses of astemizole produce insignificant anticholinergic activity or sedation, perhaps due to the poor penetration into the CNS.

Astemizole is notable for its extremely long duration of action.

This characteristic makes astemizole advantageous for the non-compliant patient since a missed dose is unlikely to alter the effectiveness of the drug.

Astemizole is used to relieve symptoms associated with chronic idiopathic urticaria and seasonal allergic rhinitis, and should not be used PRN for the immediate relief of symptoms due to its slow onset of action.

Astemizole was approved by the FDA in December 1988 and came off patent in 1997.

Astemizole has been associated with QT prolongation and torsades de pointes.

Due to low prescription usage and the availability of other agents with less propensity for adverse effects and drug interactions, this agent was discontinued from manufacture in the US by Janssen Pharmaceutica in June 1999.


  • allergic rhinitis
  • pruritus
  • urticaria

For the relief of symptoms, such as pruritus, associated with chronic idiopathic urticaria and seasonal allergic rhinitis

Side Effects

  1. anaphylactic shock
  2. anxiety
  3. appetite stimulation
  4. dizziness
  5. drowsiness
  6. headache
  7. QT prolongation
  8. syncope
  9. torsade de pointes
  10. weight gain
  11. xerostomia

Monitoring Parameters

  • ECG
  • LFTs
  • serum creatinine/BUN


  • asthma
  • breast-feeding
  • cardiac disease
  • children
  • hepatic disease
  • infants
  • neonates
  • pregnancy
  • QT prolongation
  • torsade de pointes


No information is available regarding drug interactions associated with Astemizole


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