Older antihistamines are associated with drowsiness, dizziness, constipation, upset stomach, blurry vision, a dry mouth/nose and throat, and difficulty urinating. The newer antihistamines are usually well tolerated but can cause drowsiness, dry mouth, and stomach problems.
Nasal corticosteroids can cause nasal dryness or irritation, nosebleed, throat irritation, headache, nausea,vomiting, cough, and fungal infections of the throat with long-term use.
Mast cell stabilizers can cause a short-lived stinging sensation inside the nose.
Leukotriene inhibitors are associated with unusual weakness, upset stomach, earache, dizziness, cough, headache, trouble sleeping. Serious but unlikely side effects include flu-like symptoms.
Nasal decongestants may cause a temporary burning, stinging, or dryness in the nose, a runny nose, and sneezing. Oral decongestants may cause dizziness, headache, nervousness, fast heartbeat, increased blood pressure, loss of appetite, and sleep problems.
Nasal anticholinergics can cause a bloody or dry nose, nasal congestion, dry mouth and irritated throat, bad taste in the mouth, dizziness, and nausea.
Topical corticosteroids for skin allergies can cause burning, itching, redness, and changes to skin color and thinning of skin.
Topical immunomodulators for skin allergies may cause stinging, burning, irritation, and itching at the application site. They may also cause headache and flu symptoms.
What are the drug interactions for allergy medications?
Antihistamines may interact with:
Other drugs that cause drowsiness, such as sleeping medications, narcotic pain medications, sedatives, muscle relaxants, antidepressantsand seizure medications.
Drugs with anticholinergic activity such as amitryptiline and other tricyclic antidepressants, antipsychotics like chlorpromazine, certain drugs to prevent vomiting (prochlorperazine and promethazine.
Corticosteroids may interact with:
Drugs affecting metabolism of corticosteroids, such as ketoconazole (Nizoral, Xolegel,
Extina, Ketoconazole Cream) and ritonavir (Kaletra Capsules, Kaletra Tablets, Norvir).
Leukotriene inhibitors may interact with:
Drugs that stimulate liver metabolism, such as phenytoin (Dilantin,)phenobarbital, and carbamazepine (Tegretol) – as well as the antibiotic Rifampin.
Oral decongestants may interact with:
Antidepressants, other cold or allergy medications, drugs used to treat migraines and high blood pressure.
Topical immunomodulators may interact with:
Certain antibiotics, antifungals, calcium channel blockers, and cimetidine (Tagamet).