Generic Phenergan

Common use

Phenergan is an antihistamine which used to treat different types of allergy symptoms, including itching, runny nose, sneezing, itchy or watery eyes, hives, and itchy skin rashes. It works by decreasing the effects of histamine, a chemical the body releases in response to certain irritants. Also Phenegran is used as a sedative and sleep aid for all types of patients and prevent or control nausea and vomiting, treat motion sickness. You can use it with other medications, for pain after surgery also.



Dosage and direction

Take it orally with or without food/milk. It is better take this medication with food if you want to avoid stomach upset. For treating allergy the recommended dose is 25 mg before sleeping. You can repeat the dose within two hours if necessary. For treating motion sickness the recommended dose is 25 mg twice daily.

Note: this instruction presented here just for review. It's very necessary to consult with your doctor before using. It help you to get best results.



Precautions

Do not give this drug to patients in coma Do not use alcohol while you taking Phenergan because it can extreme drowsiness. Avoid alcohol use. Phenergan may increase sensitivity to sunlight. Wear a sunscreen and protective clothing when you are exposed to the sun, it'll help you to avoid a heat stroke. Phenergan should not be used during pregnancy, becoming pregnancy or lactating without tell your doctor. Do not use before breast-feeding without doctor's advice.



Contraindications

Phenergan is not allowed to children under 2 years of age. Phenergan is contraindicated in comatose states, and in individuals known to be hypersensitive or to have had an idiosyncratic reaction to promethazine or to other phenothiazines. Also this drug is contraindicated for use in the treatment of lower respiratory tract symptoms including asthma.



Possible side effect

They may include an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Also the most possible side effects include:

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, fast or uneven heartbeats, rapid breathing;

feeling like you might pass out;

seizure (convulsions);

pale skin, easy bruising or bleeding, fever, sore throat, flu symptoms;

decreased night vision, tunnel vision, watery eyes, increased sensitivity to light;

hallucinations, agitation;

nausea and stomach pain, skin rash, and jaundice (yellowing of the skin or eyes);

urinating less than usual or not at all;

joint pain or swelling with fever, swollen glands, muscle aches, chest pain, vomiting, unusual thoughts or behavior, and patchy skin color; or

slow heart rate, weak pulse, fainting, slow breathing (breathing may stop).



Less serious include:

dizziness, drowsiness, anxiety;

blurred vision, dry mouth, stuffy nose;

ringing in your ears;

weight gain, swelling in your hands or feet;

impotence, trouble having an orgasm; or

constipation.

If you experience one of them stop using Phenegran and tell your doctor as soon as possible. Also consult with your doctor about any side effect that seems unusual.



Drug interaction

Phenergan interact with such drugs as:

lithium (Eskalith, Lithobid);

atropine (Atreza, Sal-Tropine), belladonna (Donnatal, and others), benztropine (Cogentin), dimenhydrinate (Dramamine), methscopolamine (Pamine), or scopolamine (Transderm-Scop); blood pressure medication such as guanadrel (Hylorel), guanethidine (Ismelin), propranolol (Inderal), and others; a blood thinner such as warfarin (Coumadin); bronchodilators such as ipratropium (Atrovent) or tiotropium (Spiriva); bladder or urinary medications such as oxybutynin (Ditropan, Oxytrol), solifenacin (Vesicare), and others; an MAO inhibitor such as isocarboxazid (Marplan), tranylcypromine (Parnate), phenelzine (Nardil), selegiline (Eldepryl, Emsam); medicines to treat Parkinson's disease, restless leg syndrome, or pituitary gland tumor (prolactinoma); medicine to treat stomach ulcer or irritable bowel syndrome, such as dicyclomine (Bentyl), glycopyrrolate (Robinul), hyoscyamine (Anaspaz, Cystospaz, Levsin, and others), mepenzolate (Cantil), or propantheline (Pro-Banthine). Also note that interaction between two medications does not always mean that you must stop taking one of them. As usual it affects the the effect of drugs, so consult with your doctor about how it interactions are being managed or should be managed.



Missed dose

If you forgot to take your dose in time, please do it as soon as you remember. But do not take if it is too late or almost time for your next dose. Do not take double or extra doses. Take your usually dose next day in the same regularly time.



Overdose

Symptoms of Phenergan overdose may include: severe drowsiness, dizziness, dry mouth, large pupils, flushing, nausea, vomiting, shallow breathing, and fainting. If you experience one of them call your doctor immediately.



Storage

Store at room temperature between 59-77 degrees F (15-25 degrees C) away from light and moisture, kids and pets. Do not use after expiration term.



Disclaimer

We provide only general information about medications which does not cover all directions, possible drug integrations, or precautions. Information at the site cannot be used for self-treatment and self-diagnosis. Any specific instructions for a particular patient should be agreed with your health care adviser or doctor in charge of the case. We disclaim reliability of this information and mistakes it could contain. We are not responsible for any direct, indirect, special or other indirect damage as a result of any use of the information on this site and also for consequences of self-treatment.

Clinical Verification

Last Clinically Updated: August 15, 2026

Written By

Dr. Elena Vance, PharmD

Clinical Specialist in Neuropharmacology

Fact Checked By

Marcus Thorne, MS

Biomedical Data & FDA Label Verification

Medically Reviewed By

Dr. Arthur Campbell, MD

Board-Certified Psychiatrist (ABPN)