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(Generic versions may still be available.)
Tablets and Suppositories
- Patient Information:
Details with Side Effects
Each tablet of Phenergan contains 12.5 mg, 25 mg, or 50 mg promethazine HCl. The inactive ingredients present are lactose, magnesium stearate, and methylcellulose. Each dosage strength also contains the following:
12.5 mg-FD&C Yellow 6 and saccharin sodium;
25 mg-saccharin sodium;
50 mg-FD&C Red 40.
Each rectal suppository of Phenergan contains 12.5 mg, 25 mg, or 50 mg promethazine HCl with ascorbyl palmitate, silicon dioxide, white wax, and cocoa butter. Phenergan (promethazine) Suppositories are for rectal administration only.
Promethazine HCl is a racemic compound; the empirical formula is C17H20N2S•HCl and its molecular weight is 320.88.
Promethazine HCl, a phenothiazine derivative, is designated chemically as 10H-Phenothiazine-10-ethanamine, N,N,alpha;-trimethyl-, monohydrochloride, (±)- with the following structural formula:
Promethazine HCl occurs as a white to faint yellow, practically odorless, crystalline powder which slowly oxidizes and turns blue on prolonged exposure to air. It is freely soluble in water and soluble in alcohol.
What are the possible side effects of oral promethazine (Pentazine, Phenergan)?
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Stop using promethazine and call your doctor at once if you have any of these serious side effects:
- twitching, or uncontrollable movements of your eyes, lips, tongue, face, arms, or legs;
- tremor (uncontrolled shaking), drooling, trouble swallowing, problems with balance or walking;
- feeling restless, jittery, or agitated;
- high fever, stiff muscles, confusion, sweating,...
What are the precautions when taking promethazine (Phenergan)?
See also Warning section.
Before taking promethazine, tell your doctor or pharmacist if you are allergic to it; or to any other phenothiazines (such as prochlorperazine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: breathing problems (such as asthma, chronic obstructive pulmonary disease-COPD, sleep apnea), blood/immune system problems (such as bone marrow depression), high pressure in the eye (glaucoma), heart disease (such as irregular heartbeat), high blood pressure, liver disease, certain brain disorders (such as neuroleptic malignant...
Last reviewed on RxList: 6/21/2007
This monograph has been modified to include the generic and brand name in many instances.
Additional Phenergan Information
Phenergan - User Reviews
Phenergan User Reviews
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Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
Allergies & Asthma
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