Ketotifen belongs to the classes of medications called antiallergics and asthma prophylactics. This medication is used in combination with other medications to treat mild allergic asthma in children.

Ketotifen is an anti-allergy medication that helps to reduce asthma symptoms by reducing the body's response to allergens (substances that cause allergic reactions). These allergens can often trigger an acute asthma attack. It may take several weeks of regularly using this medication before you see benefits.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. As well, some forms of this medication may not be used for all of the conditions discussed here. If you have not discussed this with your doctor or are not sure why you are using this medication, speak to your doctor. Do not stop giving this medication to your child without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as your child. It can be harmful for people to use this medication if their doctor has not prescribed it.

For children 5 years of age and older, the usual recommended dose is 1 mg twice daily, in the morning and evening.

To reduce side effects, your child's doctor may suggest you start with a lower dose and increase to the recommended dose after 5 days.

Many things can affect the dose of medication that a child needs, such as body weight or other medications. If your doctor has recommended a dose different from the one listed here, do not change the way that you are giving the medication to your child without consulting your doctor.

Use an oral syringe to measure each dose of the liquid, as it gives a more accurate measurement than household teaspoons.

Both ketotifen tablets and liquid should be swallowed. It may be taken with or without food.

Ketotifen does not relieve symptoms of an asthma or allergic attack. It must be taken regularly for it to be effective. If it becomes necessary to stop using this medication, talk to your doctor. It should not be stopped suddenly, as this may cause an increase in asthma symptoms. It is important to use this medication exactly as prescribed by your doctor. If you miss giving your child a dose, give it as soon as possible and continue with the regular dosing schedule. If it is almost time for your child's next dose, skip the missed dose and continue with the regular dosing schedule. Do not give your child a double dose to make up for the missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store both forms of ketotifen at room temperature, protect from moisture, and keep out of the reach of children.

Tablets
Each scored white tablet embossed with the name "ZADITEN" contains 1 mg of ketotifen fumarate. Nonmedicinal ingredients: starch 1500, magnesium stearate, and lactose monohydrate.

Syrup
Each 5 mL of strawberry-flavoured syrup contains 1 mg of ketotifen fumarate. Nonmedicinal ingredients: alcohol, citric acid, methyl-p-hydroxybenzoate, propyl-p-hydroxybenzoate, sodium phosphate, sorbitol solution, strawberry flavour, sucrose, and water.

This medication should not be given to anyone who:

• is allergic to ketotifen or any ingredients of this medication
• is sensitive to benzoate compounds (if taking the liquid form)

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people using this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if your child experiences these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• drowsiness
• dry mouth
• feeling excited
• increased appetite
• irritability
• nervousness
• sleep disturbances (e.g., trouble sleeping)
• slight dizziness
• weight gain

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• flu-like symptoms (e.g., sudden lack of energy, fever, cough, sore throat)
• nosebleeds
• puffy eyelid(s)
• signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don’t stop bleeding)
• signs of liver problems (e.g., abdominal pain, nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
• skin rashes and itching
• symptoms of bladder inflammation (e.g., increased need to urinate, pain in the pelvis or lower back, frequent need to urinate at night, cloudy or red urine, burning sensation when urinating)
• symptoms of respiratory infections (e.g., headache, body ache, difficulty breathing, fatigue, or fever)

Stop giving the medication to your child and seek immediate medical attention if any of the following occur:

• seizures
• signs of a severe skin reaction such as blistering, peeling, a rash covering a large area of the body, a rash that spreads quickly, or a rash combined with fever or discomfort

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are using this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Drowsiness/reduced alertness: This medication may cause drowsiness. Parents and guardians should be aware that children may experience drowsiness when they first start using this medication. They should not perform potentially hazardous tasks until you have determined how this medication affects them.

Other asthma medications: Medications used to treat and prevent asthma (e.g., b2-agonists such as salbutamol; sodium cromoglycate; corticosteroids such as beclomethasone, budesonide, and fluticasone) already in use should not be reduced immediately when treatment with ketotifen is started. Follow your doctor's instructions closely.

Seizure: Ketotifen may increase the risk of seizures, particularly if your child has a history of seizures. If you or your child have seizures or a history of seizures, discuss with your doctor how this medication may affect this medical condition, how this medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication may pass into breast milk. If you are breast-feeding and taking ketotifen, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of this medication have not been established for children under 5 years of age.

Seniors: The safety and effectiveness of this medication have not been determined for older adults and should not be used for this group of people.

There may be an interaction between ketotifen and any of the following:

• acetylcholinesterase inhibitors (e.g., donepezil, galantamine, rivastigmine)
• aclidinium
• alcohol
• amantadine
• antihistamines (e.g., azelastine, cetirizine, doxylamine, diphenhydramine, hydroxyzine, loratadine)
• antipsychotics (e.g., cariprazine, chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
• atropine
• benzodiazepines (e.g., alprazolam, clonazepam, diazepam, lorazepam)
• benztropine
• betahistine
• botulinum toxin-containing medications
• brimonidine
• buprenorphine
• butalbital
• butorphanol
• cannabis
• chloral hydrate
• clidinium
• clonidine
• darifenacin
• dimenhydrinate
• disopyramide
• domperidone
• efavirenz
• entacapone
• esketamine
• fesoterodine
• flibanserin
• flunarizine
• general anesthetics (medications used to put people to sleep before surgery)
• glucagon
• glycopyrrolate
• guanfacine
• hyaluronidase
• ipratropium
• kava kava
• lemborexant
• metoclopramide
• mirabegron
• mirtazapine
• monoamine oxidase inhibitors (e.g., moclobemide, phenelzine, tranylcypromine)
• muscle relaxants (e.g., baclofen, cyclobenzaprine, methocarbamol, orphenadrine)
• nabilone
• narcotic pain relievers (e.g., codeine, fentanyl, morphine, oxycodone, tapentadol, tramadol)
• nitroglycerin
• olopatadine
• oxybutynin
• perampanel
• pitolisant
• pizotifen
• pomalidomide
• potassium chloride
• pramipexole
• pregabalin
• prucalopride
• ropinirole
• rotigotine
• scopolamine
• seizure medications (e.g., clobazam, gabapentin, levetiracetam, phenobarbital, primidone, rufinamide, topiramate, valproic acid)
• solifenacin
• tetrabenazine
• thalidomide
• thiazide diuretics (water pills; e.g., hydrochlorothiazide, indapamide, metolazone)
• tiotropium
• tizanidine
• tolterodine
• trazodone
• tricyclic antidepressants (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
• trospium
• umeclidinium
• zolpidem
• zopiclone

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.