Potentiates other CNS depressants,alcohol,sedatives, hypnotics, barbiturates, opoid analgesics and neuroleptics.

Masks ototoxicity of aminoglycoside antibiotics.

Regular uses of hydroxyzine reduces antihistamine action.

Reduced analgesia with pethidine.

Incompatible with chloramphenicol, heparin,hydrocortisone,phenobarb and thiopentone.

Forms a precipitate with aminophylline, chlorthiazide, X-ray contrast media.

Motion sickness.

 Antihistamines Include: First Generation ( Non-selective )  Ethanolamine- Carbinoxamine. Clemastine, Diphenhydramine. Ethylenediamines- Pyrilamine, Triplennamine Akylamines- Brompheneramine, Chlorpheniramine, Dexchlor pheniramine,Pheniramine,Triprolidine Phenothiazines- Methidilazine, Promethizine, trimeprazine

 Piperidines- Azatadine, Cyproheptadine, Phenindamine Miscellaneous- Astemazole, Loratadine, Terfenadine Second Generation ( Peripherally selective ) Phthalazinone - Azelastine Piperazine - Cetrizine

Refer - Chlorpheniramine maleate 

None reported if taken along with other CNS depressants, CNS depression, paradoxical excitation in children, Dryness of mouth,blurring of vision,

Retention of urine, constipation glaucoma,bradycardia followed by tachycardia and arrthyhmias GI disturbances, blood dyscrasias. Headache,hypotension, Giddiness,parathesias and tinnitus.

Hypersens,pregnancy,lactation,obstruction to GIT/urinary outflow,paralytic ileutus,neonates.

Special precautions:

Elderly,avoid alcohol,BHP,glaucoma,epilepsy,CVS disease, hypertension.

Indications: Active and prophylactic treatment of motion sickness.

Dosage:

Average adult dose is 25mg twice daily. Take initial dose 1/2 to 1 hour before travel and repeat 8 to 12 hours later.

Refer - Chlorpheniramine maleate

 1. Phenothiazines- Patients should report any involuntary muscle movements or unusual sensitivity to sunlight.

2. Allergies- Tell your doctor if you have ever had any unusual or allergic reaction to antihistamines. Also tell your doctor if you are allergic to any other substances such as foods, or drinks.

3.Pregnancy- Methdilazine, promethazine, and trimeprazine have not been studied in pregnant women. In animal studies, promethazine has not been shown to cause birth defects.

However other phnothiazine medicines caused jaundice, and muscle tremors in a few newborn babies whose mothes received these medicines during pregnancy. Also new born babies may have blood clotting problems if promethazine is taken 2 weeks before delivery.

4.Breast feeding- Small amounts of antihistamines pass into the breast milk. Use by nursing not recommended since babies are more suseptible to the side efects of antihistamines such as unusual excitement or irritability.

Also with the use of phenothiazine-derivative antihistamines there is a chance that nursing baby may be more at risk of having difficulty in breathing while sleeping or of sudden infant death syndrome( SIDS) Also, it is possible that the flow of breast milk may be reduced in some patients

5. Children- Serious side effects such as convulsions (seizures) are more likely to occur in younger patients and would be of greater risk to infants than to older children or adults. In general chidren are more sensitive to the effects of antihistamines

Use of phenothiazine derivative antihistamines are not recommended in children who have a history of difficulty in breathing while sleeping or a family history of sudden infant death syndrome (SIDS)

6. Adolescents- Adolesants who show signs of Reyes syndrome should be not be given phenothiazine derivatives especially by injections. Uncontrolled movements that may occur with phenothiazine- derivative antihistamine may be mistakenly confused with symptoms of reyes syndrome

7. Elderly- elderly patients are more sensitive to the effects of antihistamine. Confusion, difficult or painful urination, dizziness, drowsiness, feeling faint or dryness of mouth, nose, or throat may be more likely to occur in elderly patients. Also nightmares or unusual excitement, nervousness, restlessness or irritability may be more likely tooccur in elderly patients.

8. Other medicines- When you taking antihistamines, it is important that your doctor knows if you are taking any of the following medicines- Amoxipine or Antispychotics or Methyldopa or Metoclopramide or Metryosine or Pemoline or Pimozide or Rauwolfia alkaloids - side effects of these medicines such as uncontrolled body movements, may become more severe and frequent if they are used together with phenothizine derivative

Antihistamines Anticholinergics- side effects of phenothiazine derivative- antihistamine or anticholinergics, such as dryness of mouth, may be more likely to occur Central nervous system (CNS ) depressants or Maprtiline or Tricyclic antidepressants- effects of CNS depresant or anithistamines such as dryness of mouth to become more severe

Contrast agent - if you are having an x-ray test of the head,spinal canal or nervous system for which you are going to receive an injection into the spinal canal , the histamine may increase the chance of seizures, stop taking the antihitamine 48 hours before the test

Levodopa - when used together .the levodopa may not work as it should.

MAOInhibitors- if you taking or taken within the past 2 weeks any of the MAOI the side effects of the antihistamine become more severe. These medicines should not be taken together

9. Other medical problems- Tell your doctor if you have any other medical problems- Blood discease or Heart or blood vessel disease- these medicines may cause more serious conditions to develop Enlarged prostrate or Urinary tract blockage or difficult urination- these anithistamine may cause urinary problems to become worse Epilepsy- promethazine may increase the chance of seizures

Glaucoma- these medicines may cause a slight increase in iner eye presure that may worsen the condition Jaundice- these medicine may make the condition worse Liver disease- these medicines may build up in the body which may imcrease the chance of side effects such as muscle spasms

Reyes syndrome- promethazine given by injection may increase chance of uncontrolled movements

10. Missed dose- If you are taking the medicine regularly and you miss a dose, take it as soon as possible. However ifis time for the next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Refer Antihistamines

Reports not available

Refer Antihistamines