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Ketotifen
General Information
Ketotifen is an antihistamine and partial mast cell stabilizer traditionally used to prevent asthma attacks and treat allergic conditions. Oral ketotifen used to be available over the counter and has a good safety profile. Ketotifen is frequently used off-label to treat symptoms of mast cell activation syndrome (MCAS) that frequently occur in people with Long COVID, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and types of postural orthostatic tachycardia syndrome (POTS). It can help with symptoms like itching, brain fog, GI discomfort and more.
Dosing Instructions
Please carefully follow your dosing instructions in your RTHM dashboard. Take this medication with food or milk to avoid stomach upset.
Any time you increase your ketotifen dose, you’re at risk for daytime sleepiness. We recommend increasing dosages on days you don’t have work or other significant responsibilities. Do not increase your dose if your symptoms have resolved or you are having significant side effects.
Ketotifen is most often taken in two daily doses, one in the morning and one at bedtime. However, ketotifen can make some patients drowsy, dizzy, and less alert, making the morning dose difficult to manage. In this case, doses can be combined at bedtime instead.
Ketotifen can be taken with or without food.
Please read this treatment guide in its entirety for additional important information.
General Ketotifen Tips
  • Ideally, you want to start this medication on an evening prior to a day off, as it can make you sleepy.
  • Don`'t drive or operate machinery on a new or increased dose of ketotifen until you know how it affects you.
  • Ketotifen can cause increased appetite so it is important to monitor your diet in order to avoid unwanted weight gain.
  • Ketotifen’s therapeutic effect may require up to ten weeks to take full effect. Therapy should be maintained for at least 2-3 months to determine effectiveness unless you experience significant side effects.
What To Do If I Miss a Dose
If you miss a dose, take it as soon as possible. If you are close to the time of your next dose, wait to take the next dose and then resume your normal dosing schedule. Do not “double-up” the dose.
Precautions When Starting Ketotifen
  • Ketotifen can cause drowsiness, dizziness, and affect how alert you may be. It is important not to drive or operate machinery until you know how ketotifen will affect you.
  • In some, ketotifen can cause excitability, irritability, and nervousness, making it difficult to sleep. This is due to central nervous system stimulation and is more commonly seen in children or teens.
Potential Side Effects
For some medications, it’s common to experience mild side effects as your body adjusts during the first few months of use. Mild side effects can occur when taking ketotifen and usually diminish as your body adjusts to the treatment. These side effects can include:
  • Weight gain
  • Drowsiness
  • Dry mouth
  • Increased appetite
  • Irritability
  • Nervousness
  • Unexplained nosebleeds
  • Sleep disturbance
When to Seek Medical Attention
Take medication only as directed. In the event of an accidental overdose, contact emergency services immediately.
Serious side effects with ketotifen are very uncommon, but they can occur. If you experience any of these symptoms, call your healthcare provider right away or seek emergency medical care.
  • New onset or worsening confusion or cognitive impairment
  • New onset or worsening fainting
  • New onset or worsening pounding heart beats
  • Seizures
  • Difficulty breathing or bronchospasm
  • Severe sleepiness or sedation
  • Allergic reaction: skin rash, itching, hives, swelling of feet or hands
Interactions with Ketotifen
  • You should not take ketotifen if you are on any of the following medications. If your provider wants to start you on any of these medications, make sure to tell your provider you are taking ketotifen
    • Bupropion (Wellbutrin)
    • Donepezil (Aricept)
    • Pitolisant (Wakix)
    • Bromperidol (Bromidol, Impromen)
    • Orphenadrine
    • Oxomemazine
    • Kratom
    • Thalidomide
    • Amifampridine (Firdapse)
Who Should Not Take Ketotifen
Contraindications associated with the use of ketotifen include:
  • If you have more than 2 alcoholic beverages per day. Alcohol can exacerbate the side effects of ketotifen.
  • Severe kidney or liver disease can adversely affect the metabolism of ketotifen
  • If you have symptoms of fainting (syncope), near fainting (near-syncope) or seizures. Ketotifen can exacerbate syncope and seizures.
  • If you have an allergy to ketotifen or any of its active ingredients
  • Ketotifen interacts with several medications (see section above). You should not take ketotifen while on these other medications.
What If I Become Pregnant While Taking This Medication?
  • RTHM does not prescribe ketotifen for women who are pregnant or planning to become pregnant. If this medication is benefitting you, please have a discussion with your OB-GYN about the risks versus benefits of continuing this medication during your pregnancy.
  • If you become pregnant while taking this medication, ketotifen is FDA-rated as a pregnancy category C, meaning the potential risk cannot be ruled out.
Medication Storage
  • Keep this medication in the container provided by the pharmacy. Ensure it is properly closed and out of the reach of children. Store at room temperature and away from excess heat, direct light, and moisture (not in the bathroom).
  • Do not share this medication with anyone else.
  • Do not throw away unwanted or expired medications. Do not flush down the toilet or pour down the drain. Ask your local pharmacist about local drug take back programs to discard your medication
Questions?
If you have questions about this medication, please contact us by using our support form. We generally respond within 2 business days. If you have a more urgent issue, please seek care from your local primary care provider, urgent care or emergency services.
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