Ketotifen (Oral)

Ketotifen is an oral antihistamine most commonly prescribed for the treatment of asthma in minors.


Ketotifen is asthma medicine which is taken daily alongside other asthma medications to reduce asthma attacks. It reduces the daily requirements of antiasthma drugs, but it does not relieve an asthma attack that has started. The drug is administered orally only under the doctor's prescription and it can either be taken with or without food. It works by inhibiting substances in the body that cause asthma symptoms and inflammation. For quick and efficient relief, continuous intake is recommended. Ketotifen contains carbohydrates, hence the healthcare provider should be informed if the patient is on any diet like the low sugar diet. The dosage depends on the body weight, age and the response shown after the first dosage. It does not work immediately hence it is not suitable for the onset of sudden asthma attacks. In most cases, it takes 2 to 3 months to see the results of the drug.

Conditions Treated

  • Asthma
  • Allergic rhinitis
  • Allergic conjunctivitis
  • Exercise-induced urticaria
  • Cold-induced urticaria

Type Of Medicine

  • Antihistamine

Side Effects

Along with the needed effects, Ketotifen may sometimes cause unwanted effects. Not all of the effects mentioned here may occur, but it's important to check with the doctor if they do. The most common effects are diarrhea, chills, cough, fever, general discomfort, headache, loss of appetite and sweating. Some patients have also reported joint pains, nausea, runny nose, sore throat, muscle pains and aches, vomiting, and trouble sleeping. Most of the effects do not require medical attention as they stop after some time.

Ketotifen may also cause some severe effects although their occurrence is rare. Cases of patients having convulsions, stomach or abdominal pains, cloudy or bloody urine, clay-colored stools and peeling, itching and blistering of the skin has been reported. Some patients may have rashes, dark urine, muscle jerking or spasm of all extremities, loss of consciousness, frequent urge to urinate and unpleasant breath. Immediate medical attention is required when the patient's skin and eyes turn yellow or if they start to vomit blood.

Ketotifen may cause blurred vision, disorientation, convulsions, drowsiness, dizziness, and palpitations in the case of overdose. It may also cause irregular, fast or pounding heartbeats. Also, some patients experience excess sweating, unusual tiredness, lightheadedness or faintness when suddenly waking up from a sitting or sleeping position and hyperexcitability in overdose cases. All overdose effects need immediate medical help to provide quick relief.

Most of the side effects tend to go away after some time as the patient's body continues to adjust itself to the drug. Also, your doctor may give some tips or advice on some of the methods that you can use to reduce the impact of the effects. The effects may vary from one patient to another, and therefore it's crucial to let your doctor know when you have a question or when they become bothersome.

Ketotifen may cause effects like increased appetite, irritability, mouth dryness, bloody nose, weight gain, drowsiness, nervousness, unexplained nosebleeds or swelling eyelids. Other effects are not listed here that may occur. It is advisable to always check with the doctor in case you notice other effects. You can also report the side effects to FDA at 1-800-FDA-1088.


Ketotifen is administered into the body orally (by mouth) two times per day. The dose given varies in different patients hence it's important to carefully follow the doctor's instructions as well as the label. The information provided below is the average Ketotifen dosage. If the doctor prescribes a different dosage, do not change it.

The medicine amount taken depends on the patient's condition and the strength of the drug. It is also based on how the patient responses to the initial dosage. It also depends on the intake frequency: the time taken between one dose and the other, the number of prescriptions and the period the patient is under medication. In many cases, the doctor may first give the patient a small amount and adjust it slowly to reduce the side effects.

The usual oral dosage (tablets) for asthma is:

Children above three years and adults - 1 milligram(mg) or 5 milliliters (ml) two times per day, one in the morning and one in the evening.

Infants and children between 6 months to 3 years - the dose is determined by the healthcare provider, and it depends on the body weight. Usually, it is 0.25ml (0.05mg) per kilogram administered twice per day.

During pregnancy, Ketotifen should only be used when needed. The patient should, therefore, disclose to the doctor when they are pregnant or plan to get pregnant. Both the risks and benefits of using the drugs will be outweighed before the drug is given. The medicine is also excreted in breast milk. It is therefore not advisable to use the drug while breastfeeding as it can harm the child.

In case an overdose is suspected, seek immediate medical attention. You can also contact your local poison control or emergency room. If you skip a dose, take it as soon as possible once you remember; however, if it's almost time for the following dose, you can entirely skip the missed dose and go back to the regular schedule. This will help in preventing double dosing. Also, do not share the dose with somebody else.


Drugs interact in the body irrespective of the route they were administered to the body in. Some of these medications may cause dangerous interactions which may increase the risk of having adverse side effects or reduce the effectiveness of others. For this reason, some medicines should not be used together with others. For some drugs, it is necessary to use them with others even if they cause interactions. When taking Ketotifen, you should let your doctor know if you are taking any of the drugs mentioned below.

  • Bupropion
  • Donepezil

The patient is required to keep a record of all the drugs they are taking including the nonprescribed ones, vitamin supplements or herbal medicines. This will help the doctor in determining whether you are taking any prescription that could cause an interaction. Also, report any medications that can cause drowsiness such as the anti-anxiety drugs, sleeping pills, some antihistamines like diphenhydramine, muscle relaxants, psychiatric drugs, anti-seizure drugs and narcotic pain relievers. Some cold and cough preparations can also cause drowsiness so consult with your doctor to avoid creating drug interactions. Do not start using another medicine without the doctor's approval.

Some medications should not be used together with some foods or drinks since interactions can take place. Avoid using tobacco or alcohol when taking Ketotifen since interactions can take place. Discuss with your doctor if you are taking tobacco or alcohol.


Some medical problems can affect Ketotifen. Ensure that you inform your healthcare provider if you have any of these medical issues.

For patients with diabetes mellitus, the medicine may interfere with the sugar levels in the body. In case you notice any change in your urine and blood sugar levels or blood, inform the doctor immediately. Ketotifen may increase the risks of having convulsions in patients with epilepsy.

It is vital that the doctor keeps checking your progress at routine visits, this lets the doctor determine if the drug is working well for you or not. The dosage may be changed or the medication discontinued entirely if it's not working on a patient or where it causes severe unwanted effects.

The drug may make some patients dizzy, less alert or drowsy. Make sure you do not drive or operate machinery immediately after taking Ketotifen. The medicine can also make some patients become nervous, irritated, excited or have sleeping troubles. These can be symptoms of central nervous system stimulation, and it occurs mostly in small children.

Let your doctor know if you are allergic to the drug or any of its ingredients. You can ask for the drug's ingredients to be sure. Also, inform your healthcare provider if you have any other types of allergies like food, preservatives, animals and dyes allergies. For the nonprescribed products, carefully go through the instructions and the labels carefully.

Ketotifen should not be used by breastfeeding mothers. This is because the drug is passed in the milk to the baby and it may harm the child. It's therefore essential to inform the doctor if you are lactating before the drug is administered. The safety of the medicine during pregnancy has not yet been determined hence the medication is only given after outweighing the benefits and risks of the drug.


Store the drug at room temperature or below 77 degrees. Keep it away from direct sunlight and moisture but do not freeze or store in the bathroom. Keep it in a safe place away from the reach of children and pets. Do not flush it down the toilet after use or pour in a drain unless you have been instructed to do so. If it has expired or it is no longer needed, discard it in a safe place. Consult with your healthcare provider or local waste disposal company to get more information on how to discard it safely.


Ketotifen is used in the long-term maintenance of asthma to decrease or prevent troubled breathing or wheezing caused by allergic asthma. It is usually used together with other asthma medications like inhaled beta agonists like salbutamol or corticosteroids like prednisone. It is an antihistamine that controls asthma symptoms and can improve the exercise ability of a child. Ketotifen does not work immediately hence it is not sufficient medicine for sudden attacks of breath/asthma shortness.

Ketotifen is taken orally in the form of tablets or syrup and is taken with or without food. The usual frequency intake is two times per day although your healthcare provider may adjust the dosage depending on the condition. However, the drug interacts with Bupropion and Donepezil hence the doctor should be made aware of the other medications the patient may be taking. Also, Ketotifen is passed in human milk while breastfeeding and therefore it should not be taken while breastfeeding to avoid harming the baby.

Ketotifen may sometimes cause unwanted effects like drowsiness, increase weight/appetite, nervousness and trouble sleeping. Most patients do not experience severe effects, but it's advisable to always check with the doctor when a side effect becomes bothersome. Patients with diabetes mellitus or epilepsy should take the drug with caution as it might worsen the condition. For the drug to be beneficial, it should be taken at the same time every day and patients should avoid skipping some doses. Patients should not stop taking it without the doctor's approval. It may take 2-3 months to see the effectiveness of the drug.