Antihistamines are commonly used to treat sneezing, rash, itching, hives, runny nose and watery eyes due to the common cold and allergies. They can also be used to treat anxiety, motion sickness and insomnia. Antihistamine side effects tend to affect most patients taking this type of medication, but they often subside within two weeks of taking this type of medication. However, sometimes antihistamine side effects will persist or be particularly bothersome for some patients. If this occurs the patient may need to try a different antihistamine, have their dose adjusted or completely stop taking antihistamine medications.
The most common antihistamine side effects often affect most patients to some degree. The majority of patients will find these antihistamine side effects tolerable and not long-lasting. The most common antihistamine side effects include drowsiness, dry mouth, dry nose, dizziness, irritability, headache, vision changes, stomach upset and loss of appetite. If any of these side effects are significant or long-lasting, the patient should contact their physician.
Some antihistamine side effects are considered much more serious. These side effects are not as common, but they do occur. The more serious antihistamine side effects include breathing difficulties, difficulty urinating, ringing in the ears and irregular or pounding heartbeat. These antihistamine side effects are considered serious and in some cases warrant immediate medical attention. All patients experiencing these side effects should alert their physician and seek emergency medical attention if necessary.
Certain precautions should be taken when taking an antihistamine because certain medical conditions, drugs and other factors could lead to undesirable antihistamine side effects. Patients who have narrow angle glaucoma, overactive thyroid, stomach ulcers, lung problems, difficulty urinating, seizures, an enlarged prostate, high blood pressure and heart disease should avoid antihistamines because adverse reactions may occur.
When taking this type of medication patients should be careful when standing because the antihistamine side effect dizziness, may occur in a more significant manner. Those taking this medication should limit their alcohol intake and avoid performing any activities in which they need to be alert because this type of medication can cause drowsiness. Alcohol can increase a patient’s drowsiness. Pregnant and breastfeeding women may not be able to take this type of medication.
Antihistamine side effects and antihistamines in general may be dangerous for the elderly and children under twelve because those of these age groups are often more sensitive to antihistamines and their effects. Children under twelve cannot be prescribed long-acting forms.
Antihistamine side effects and its general affects may be made more pronounced by certain drugs and medications. Common drugs and medications that may increase antihistamine side effects include sleeping pills, other cold and allergy medications, sedatives, narcotic pain relievers, tranquilizers, seizure medications, muscle relaxers and antidepressants. Antihistamines may also affect allergy testing so those expecting this type of test should consult their physician for information on how many days before the test they need to stop taking their antihistamine.
If a patient misses a dose they should take it as soon as they remember unless it it almost time for their next dose. They should then skip the missed dose and resume their normal dosing schedule. Taking more than prescribed can result in an increase in antihistamine side effects and sometimes, overdose.