Allergic reactions are treated with diphenhydramine as it works as an antihistamine. When the body suffers from various kinds of allergic reactions then histamine is released. Even the common cold and certain viral infections cause histamine to release though to a much lesser extent. All cells have receptors and when histamine attaches itself to the receptors the cells are stimulated and so sneezing, itching and an increase in mucus production results.
Once antihistamines attach themselves to the cell receptors and manage to prevent the histamines from doing the same the cells can no longer be stimulated and so histamines no longer produce the allergic reactions. Diphenhydramine is also used as a sedative as it causes drowsiness and helps to block acetylcholine from acting, this is also known as the anticholinergic affect. Diphenhydramine has been approved by FDA as early as 1946.
Before starting with diphenhydramine make sure you inform your doctor if you are allergic to it or to any other medication that you are taking.
Mention to the doctor specifically if you are taking any other prescribed diphenhydramine products including those used for the skin. Also mention if you are taking any medicines for colds, hay fever, allergies or medicines for anxiety, depression, seizures, muscle relaxants, narcotic painkillers, sedatives, sleeping pills and tranquilizers. You should also tell the doctor about any non-prescribed medications you might be taking or plan to take like herbal remedies, vitamins and nutritive supplements.
You must also communicate to the doctor if you have ever suffered any of the following medical conditions like asthma, emphysema, chronic bronchitis, or other types of lung disease, glaucoma that is leading to loss of vision, ulcers, any difficulty in urinating due to an enlarged prostrate gland, any heart disease, high blood pressure, seizures, or an overactive thyroid gland. In case you have been advised a low sodium diet then tell the doctor so especially if he suggests you take the liquid form of diphenhydramine.
Also mention to your doctor if you are pregnant or plan to get pregnant and whether you are breast feeding your baby. In case you become pregnant while taking diphenhydramine then notify the doctor immediately.
In case the dentist or the surgeon plan a surgical intervention for you then tell the dentist or the surgeon that you are taking diphenhydramine.
As diphenhydramine has the tendency to cause drowsiness, you must avoid driving a car or operating machinery till you know how this medication affects you. Alcohol consumption could very well add to the effect of drowsiness so you must steer clear of all alcoholic beverages.
Mention if you suffer from phenylketonuria where a special diet is required to prevent mental retardation as some brands of the chewable and rapid dissolving tablets of diphenhydramine may contain the sweetener aspartame which is a source of phenylalanine.
If you are over 65 years then before you start on diphenhydramine discuss with your doctor the risks and benefits of the medication as it is not as safe as some of the other medications that are used to treat similar conditions.
Allergic symptoms like rash, itching, watery eyes, itching nose, throat and eyes, cough, runny nose and sneezing caused by hay fever and common cold are relieved with diphenhydramine as it works as an antihistamine.
Symptoms like nausea, dizziness and vomiting caused by motion sickness are prevented with diphenhydramine. It is also used to relax muscles to enable a person to fall asleep.
During an allergic reaction the body produces a substance known as histamine. Diphenhydramine works by blocking the work of histamines and also another natural substance called acetylcholine. This is effective in successfully drying up watery eyes and runny noses.
Unless especially directed by the doctor, children below 6 years should not be given diphenhydramine to treat coughs and colds as it is neither safe nor effective. The long acting tablets of diphenhydramine are not to be given to children below 12 years. Your pharmacist or doctor could advice you on the safe use of this medication. Children should not be given this product to make them sleepy.
Diphenhydramine does not shorten the length of the common cold and nor does it cure it but it can cause serious side effects. To reduce side-effects the medication must be taken exactly as directed and should not be combined with other cough and cold medicines that might contain the same or similar ingredients. Perhaps you could ask the doctor or pharmacist to advise you on other methods of relieving cough and cold symptoms like using a humidifier and saline nose drops or spray and drinking plenty of fluids also helps.
Tremors and muscle stiffness caused by Parkinson's disease are also treated with diphenhydramine either alone or in combination with other medications. The side-effects of some psychiatric drugs that cause involuntary movements are also treated with diphenhydramine.
Use diphenhydramine as directed on the package or according to your doctor's directions. In case there is some confusion about the directions then ask the doctor, pharmacist or nurse to explain it to you.
The dose is to be taken with a full glass of water, with or without food. For motion sickness it should be taken 30 minutes before proceeding to travel, then with meals and finally at bedtime for the duration of the journey.
Diphenhydramine is to be taken 30 minutes before bedtime if used as an aid to help you to get to sleep.
The liquid form of diphenhydramine should be measured out in a dose-measuring cup or spoon which is available with the pharmacist. Get one from him and do not use a normal spoon to measure the medicine.
Do not take more than the prescribed amount of medication. In a twenty-four hour period the dose should not be more than 300 mg. In case you miss a dose then take it as soon as you remember unless it is too close to the next scheduled dose. You will then have to take the regular dose and not the missed one as that would double the dose of medication presently prescribed by the doctor.
It prevents the naturally occurring substance histamine from working properly as it reduces swelling, itching, sneezing and watery eyes which histamine stimulates.
Herbal remedies like valerian and kava kava may cause additional drowsiness and so combining these with diphenhydramine should be avoided. Ginkgo biloba leaf extract has a German Commission E and is indicated for vertigo but since it has not been researched in combination with antihistamines it is not recommended for use. Alcohol on the other hand can cause extreme sedation and must be totally avoided. Smoking marijuana also sees an increase in drowsiness and causes the mouth to dry; impaired thinking could also see a marked increase. Exposure to the sun should be avoided as it could cause photosensitivity. Some chemicals in the environment like the insecticides Aldrin, Dieldrin and Chlordane could render diphenhydramine ineffective and useless. Sevin on the other hand could help to increase the sedative effect.
Keep diphenhydramine out of reach of children and pets in the same tightly closed container it came in. Do not store in the bathroom as it should not be exposed to heat and moisture. The medication can be stored at room temperature. Dispose of any unused and outdated medication safely and according to the advice of the pharmacist.