Antihistamines, Phenothiazine-derivative (Systemic)

Proper Use of This Medicine

Antihistamines are used to relieve or prevent the symptoms of your medical problem. Take them only as directed . Do not take more of them and do not take them more often than recommended on the label, unless otherwise directed by your doctor. To do so may increase the chance of side effects.

For patients taking this medicine by mouth :

• Antihistamines can be taken with food or a glass of water or milk to lessen stomach irritation if necessary.
• If you are taking the extended-release capsule form of this medicine, swallow it whole. Do not break, crush, or chew before swallowing.

For patients taking promethazine for motion sickness :

• Take this medicine 30 minutes to 1 hour before you begin to travel.

For patients using the suppository form of this medicine :

• To insert suppository: First remove the foil wrapper and moisten the suppository with cold water. Lie down on your side and use your finger to push the suppository well up into the rectum. If the suppository is too soft to insert, chill the suppository in the refrigerator for 30 minutes or run cold water over it before removing the foil wrapper.

For patients using the injection form of this medicine :

• If you will be giving yourself the injections, make sure you understand exactly how to give them. If you have any questions about this, check with your health care professional.

Dosing - The dose of an antihistamine will be different for different patients. Follow your doctor's orders or the directions on the label . The following information includes only the average doses of antihistamines. If your dose is different, do not change it unless your doctor tells you to do so.

The number of capsules or tablets or teaspoonfuls of liquid that you take depends on the strength of the medicine. Also, the number of doses you take each day and the time between doses depends on whether you are taking a short-acting or long-acting form of antihistamine .

For methdilazine
• For regular (short-acting) oral dosage forms (tablets or liquid):
  • For allergy symptoms:
    • Adults and teenagers - 8 milligrams (mg) every six to twelve hours as needed.
    • Children younger than 3 years of age - Use and dose must be determined by your doctor.
    • Children 3 to 12 years of age - 4 mg every six to twelve hours as needed.

For promethazine
• For regular (short-acting) oral dosage forms (tablets or liquid):
  • For allergy symptoms:
    • Adults and teenagers - 10 to 12.5 mg four times a day before meals and at bedtime; or 25 mg at bedtime as needed.
    • Children younger than 2 years of age - Use and dose must be determined by your doctor.
    • Children 2 years of age and older - Your doctor will determine dose based on the weight and/or size of the child. Children usually are given 5 to 12.5 mg three times a day or 25 mg at bedtime as needed.
  • For nausea and vomiting:
    • Adults and teenagers - 25 mg for the first dose, then 10 to 25 mg every four to six hours if needed.
    • Children younger than 2 years of age - Use and dose must be determined by your doctor.
    • Children 2 years of age and older - Your doctor will determine dose based on the weight and/or size of the child. Children usually are given 10 to 25 mg every four to six hours as needed.
  • For prevention of motion sickness:
    • Adults and teenagers - 25 mg taken one-half to one hour before traveling. The dose may be repeated eight to twelve hours later if needed.
    • Children younger than 2 years of age - Use and dose must be determined by your doctor.
    • Children 2 years of age and older - Your doctor will determine dose based on the weight and/or size of the child. Children usually are given 10 to 25 mg one-half to one hour before traveling. The dose may be repeated eight to twelve hours later if needed.
  • For vertigo (dizziness):
    • Adults and teenagers - 25 mg two times a day as needed.
    • Children younger than 2 years of age - Use and dose must be determined by your doctor.
    • Children 2 years of age and older - Your doctor will determine dose based on the weight and/or size of the child. Children usually are given 10 to 25 mg two times a day as needed.
  • For use as a sedative:
    • Adults and teenagers - 25 to 50 mg.
    • Children younger than 2 years of age - Use and dose must be determined by your doctor.
    • Children 2 years of age and older - Your doctor will determine dose based on the weight and/or size of the child. Children usually are given 10 to 25 mg.
• For injection dosage form:
  • For allergy symptoms:
    • Adults and teenagers - 25 mg injected into a muscle or into a vein.
    • Children younger than 2 years of age - Use and dose must be determined by your doctor.
    • Children 2 years of age and older - Your doctor will determine dose based on the weight and/or size of the child. Children usually are given 6.25 to 12.5 mg injected into a muscle three times a day or 25 mg at bedtime as needed.
  • For nausea and vomiting:
    • Adults and teenagers - 12.5 to 25 mg injected into a muscle or into a vein every four hours as needed.
    • Children younger than 2 years of age - Use and dose must be determined by your doctor.
    • Children 2 years of age and older - Your doctor will determine dose based on the weight and/or size of the child. Children usually are given 12.5 to 25 mg injected into a muscle every four to six hours as needed.
  • For use as a sedative:
    • Adults and teenagers - 25 to 50 mg injected into a muscle or into a vein.
    • Children younger than 2 years of age - Use and dose must be determined by your doctor.
    • Children 2 years of age and older - Your doctor will determine dose based on the weight and/or size of the child. Children usually are given 12.5 to 25 mg injected into a muscle.
• For suppository dosage form:
  • For allergy symptoms:
    • Adults and teenagers - 25 mg inserted in rectum. Another 25-mg suppository may be inserted two hours later if needed.
    • Children younger than 2 years of age - Use and dose must be determined by your doctor.
    • Children 2 years of age and older - Your doctor will determine dose based on the weight and/or size of the child. Children usually are given 6.25 to 12.5 mg inserted into the rectum three times a day or 25 mg at bedtime as needed.
  • For nausea and vomiting:
    • Adults and teenagers - 25 mg inserted into the rectum for the first dose, then 12.5 to 25 mg every four to six hours if needed.
    • Children younger than 2 years of age - Use and dose must be determined by your doctor.
    • Children 2 years of age and older - Your doctor will determine dose based on the weight and/or size of the child. Children usually are given 12.5 to 25 mg inserted into the rectum every four to six hours as needed.
  • For vertigo (dizziness):
    • Adults and teenagers - 25 mg inserted into the rectum, two times a day as needed.
    • Children younger than 2 years of age - Use and dose must be determined by your doctor.
    • Children 2 years of age and older - Your doctor will determine dose based on the weight and/or size of the child. Children usually are given 12.5 to 25 mg inserted into the rectum two times a day as needed.
  • For use as a sedative:
    • Adults and teenagers - 25 to 50 mg inserted into the rectum.
    • Children younger than 2 years of age - Use and dose must be determined by your doctor.
    • Children 2 years of age and older - Your doctor will determine dose based on the weight and/or size of the child. Children usually are given 12.5 to 25 mg inserted into the rectum.

For trimeprazine
• For regular (short-acting) oral dosage forms (tablets or liquid):
  • For allergy symptoms:
    • Adults and teenagers - 2.5 mg four times a day as needed.
    • Children younger than 2 years of age - Use and dose must be determined by your doctor.
    • Children 2 to 3 years of age - 1.25 mg at bedtime or three times a day as needed.
    • Children 3 to 12 years of age - 2.5 mg at bedtime or three times a day as needed.
• For long-acting oral dosage forms (extended-release capsules):
  • For allergy symptoms:
    • Adults and teenagers - 5 mg every twelve hours as needed.
    • Children younger than 6 years of age - Use and dose must be determined by your doctor.
    • Children 6 to 12 years of age - 5 mg once a day as needed.

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

Storage - To store this medicine:

• Keep out of the reach of children, since overdose may be very dangerous in children.
• Store away from heat and direct light.
• Do not store the capsule or tablet form of this medicine in the bathroom medicine cabinet, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Keep the liquid form of this medicine from freezing.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.