Promethazine also acts as an antihistamine. Dosage … Cough.

It also acts to block other receptors in the vomiting centre (serotonin receptors). Skip the missed dose if it is almost time for your next scheduled dose. Be careful if you drive or do anything that requires you to be awake and alert. This helps prevent and relieve the typical symptoms of an allergic reaction. Phenergan can cause side effects that may impair your thinking or reactions. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. You should not take Phenergan if you are allergic to promethazine or to similar medicines such as chlorpromazine, fluphenazine, mesoridazine, perphenazine, prochlorperazine, thioridazine, or trifluperazine.You should not take Phenergan if you have asthma or another lower respiratory tract disorder.To make sure Phenergan is safe for you, tell your doctor if you have:asthma, chronic obstructive pulmonary disease (COPD), sleep apnea, or other breathing disorder;low levels of calcium in your blood (hypocalcemia); orif you have ever had a serious side effect while using promethazine or any other phenothiazine.It is not known whether Phenergan will affect an unborn baby. Promethazine is a prescription drug. While an exact dosage of parenteral promethazine is not provided by the manufacturer, the FDA-approved product label recommends not exceeding one-half of the recommended adult dosage (12.5—25 mg/dose). There are many other medicines that can interact with promethazine. 1.1 mg/kg/dose PO or PR (Max: 25 mg/dose). Children 6-12 years: One to two 10mg tablets, or 10 to 25mL of the elixir as a single dose at night, or one 10mg tablet, or 10mL of the elixir, two to three times daily. Promethazine is favored because it is a reasonable treatment for lots of different common canine problems. 6-12 years: 2.5-5 mL PO 4-6hr, up to 25 mg/60 mg (20 mL) in 24 hr Get up slowly and steady yourself to prevent a fall.Drinking alcohol can increase certain side effects of Phenergan. For motion sickness, Phenergan is usually started within 1 hour before traveling. Be careful if you drive or do anything that requires you to be alert. Tell your doctor if you are pregnant or plan to become pregnant while using this medicine.It is not known whether promethazine passes into breast milk or if it could affect a nursing baby. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.Stop using Phenergan and call your doctor at once if you have:uncontrolled muscle movements in your face (chewing, lip smacking, frowning, tongue movement, blinking or eye movement);easy bruising or bleeding (nosebleeds, bleeding gums);sudden weakness or ill feeling, fever, chills, sore throat, mouth sores, red or swollen gums, trouble swallowing; orvery stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.Side effects such as confusion and severe drowsiness may be more likely in older adults.This is not a complete list of side effects and others may occur. _____ 2. Please be aware that we do not give advice on your individual medical condition, if you want advice please see your treating physician. Select one or more newsletters to continue. Tell your doctor if you regularly use any of these medicines.Also tell your doctor if you are using any of the following medicines: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;bronchodilators such as ipratropium (Atrovent) or tiotropium (Spiriva);bladder or urinary medications such as oxybutynin (Ditropan, Oxytrol), solifenacin (Vesicare), and others;a MAO inhibitor such as isocarboxazid (Marplan), tranylcypromine (Parnate), phenelzine (Nardil), or selegiline (Eldepryl, Emsam) or methylene blue injection; ormedicines to treat Parkinson's disease, restless leg syndrome, or pituitary gland tumor (prolactinoma); ormedicine 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).This list is not complete and there are many other medicines that can interact with Phenergan. Follow all directions on your prescription label. Promethazine also acts on receptors in the gut (muscarinic receptors) to decrease the amount of fluid secreted from the lining of the gut and decrease the actions of the gut muscles.