Brand names Hismanal, Pollen-eze
Used in the following combined preparations None
General Information
Astemizole is an antihistamine with a prolonged duration of action. Its main use is in the treatment of allergic rhinitis, particularly hay fever.
Taken as tablets or liquid, it reduces irritation of the eyes and nose as well as sneezing. Allergic skin conditions – for example, chronic urticaria (hives) – may also be helped by astemizole.
The primary difference between this drug and the older, traditional antihistamines is that it has little or no sedative effect on the central nervous system. It is therefore useful for people who need to avoid drowsiness – for example, at work.
Astemizole’s slow onset of full therapeutic effect makes it unsuitable for treating allergic conditions such as reactions to food and the intense itching of skin reactions. Moreover, because of the drug’s extended action in the body, it should be discontinued for at least 4 weeks prior to skin testing for allergy.
Information For Users
Follow instructions on the label. Call your doctor if symptoms worsen.
How taken
Tablets, liquid.
Frequency and timing of doses
Once daily.
Adult dosage range
Not to exceed 10mg daily.
Onset of effect
1-3 hours.
Duration of action
Up to 3 weeks.
Diet advice
None.
Storage
Keep in a closed container in a cool, dry place out of the reach of children.
Missed dose
No cause for concern. If it is almost time for your next dose, take a single dose now and skip the next.
Stopping the drug
Can be safely stopped as soon as you no longer need it.
Exceeding the dose
An occasional unintentional extra dose is unlikely to be a cause for concern.
But if you notice any unusual symptoms, or if a large overdose has been taken, notify your doctor.
Possible Adverse Effects
Weight gain, perhaps due to an increase in appetite, occurs occasionally with astemizole; other side effects are very rare. A rash may be a sign of an unusual allergic reaction.
Astemizole can rarely produce dangerous changes in heart rhythm. If palpitations develop or you feel faint, seek medical help without delay.
Quick Reference
Drug group Antihistamine
Overdose danger rating Medium
Dependence rating Low
Prescription needed No
Available as generic No
Special Precautions
Be sure to consult your doctor or pharmacist before taking this drug if:
You have a long-term liver problem.
You have had a previous allergic reaction to astemizole.
You have had heart problems.
You are taking other medications.
Pregnancy
Safety in pregnancy not established. Discuss with your doctor. Adequate contraception should be continued for several weeks after stopping the drug.
Breast-feeding
The drug passes into the breast milk. Discuss with your doctor.
Infants and children
Not recommended under 6 years. Reduced dose necessary in older children.
Over 60
Reduced dose may be necessary.
Driving and hazardous work
Problems are unlikely. However, avoid such activities until you know how astemizole affects you.
Alcohol
Avoid excessive amounts.
Interactions
Antifungal drugs
Ketoconazole, fluconazole, itraconazole, and possibly other antifungal drugs increase levels of astemizole, and may lead to adverse effects on the heart.
Anticholinergic drugs
The anticholinergic effects of astemizole may be increased by all drugs that have anticholinergic effects, including antipsychotics and tricyclic antidepressants.
Antidepressants/antipsychotics
These drugs increase the possibility of abnormal heart rhythms.
Diuretics
These drugs may increase the risk of adverse effects on the heart.
Erythromycin
This drug may increase levels of astemizole and lead to adverse effects on the heart.
Prolonged Use
Astemizole should be discontinued at least 4 weeks prior to allergy skin testing.
