Doxecitine and doxribtimine

Doxecitine and doxribtimine is used to treat thymidine kinase 2 deficiency (TK2d; genetic disorder that causes progressive muscle weakness). Doxecitine and doxribtimine are both in a class of medications called pyrimidine nucleosides. They work by replacing the mitochondrial DNA absent in TK2d that leads to muscle weakness.

Doxecitine and doxribtimine comes as a powder to be mixed with water to take by mouth. Take with food three times a day. Each dose should be taken 6 hours apart, plus or minus 2 hours on either side. Take doxecitine and doxribtimine at around the same times every day.

Take doxecitine and doxribtimine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

You will be provided a ZX2000 administration kit to prepare and give the dose of doxecitine and doxribtimine. It is important to only use this to prepare and give the dose.

You will be told how many packets you will need to use to get your daily dose. Each packet requires 40 mL of room temperature water.

To mix doxecitine and doxribtimine:

• obtain the prescribed number of packets for a full daily dose.
• pour the prescribed amount of water into the mixing bottle.
• add the prescribed number of packets to the mixing bottle.
• place the dosing cup on top of the bottle and screw tightly.
• mix by inverting bottle back and forth at least 20 times. If powder remains, repeat until it is completely dissolved. The mixture may appear cloudy and may have some residual particles at the bottom or top.

To give a dose of doxectine and doxribtimine:

• before each dose, invert the mixing bottle back and forth at least 3 times.
• use either the dosing cup or oral syringe to give the medicine based on the volume to be given. See the Patient Instructions for Use for guidance.
• give the prescribed amount of doxectibine and doxribtimine in 3 divided doses.
• discard any unused mixture 16 hours after adding the water to the powder or after the 3 daily doses are given, whichever comes first.

If giving through a feeding tube, follow the instructions of the feeding tube manufacturer on how to give the dose. Flush any remaining solution in the syringe or feeding tube until no solution is remaining.

Your doctor will probably start you on a low dose of doxecitine and doxribtimine and gradually increase your dose, not more than once every 2 weeks.

You will be given Patient Instructions for Use. Read the instructions carefully and ask your doctor or pharmacist any questions you may have.

Doxecitibe and doxribtimine controls TK2d but does not cure it. Do not stop taking doxecitibe and doxribtimine without talking to your doctor.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Before taking doxecitine and doxribtimine,

• tell your doctor or pharmacist if you are allergic to this medication, any part of this medication, or any other medications, foods or substances. Tell your doctor or pharmacist about the allergy and what symptoms you had.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take.
• tell your doctor if you have or have ever had liver or kidney diseases.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking doxecitine and doxribtimine, call your doctor.

Unless your doctor tells you otherwise, continue your normal diet.

Take the missed dose as soon as you remember it. However, if it is within 2 hours of the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Doxecitine and doxribtimine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• diarrhea
• abdominal pain
• vomiting

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

• yellowing of the skin or whites of the eyes, extreme tiredness, low of appetite, light colored stools, dark urine, abdominal pain

Doxecitine and doxribtimine may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (https://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). The mixture of powder after water has been added can be stored at room temperature or in the refrigerator.

Keep all medication out of sight and reach of children as many containers are not child-resistant. Always lock safety caps. Place the medication in a safe location – one that is up and away and out of their sight and reach. https://www.upandaway.org

Dispose of unneeded medications in a way so that pets, children, and other people cannot take them. Do not flush this medication down the toilet. Use a medicine take-back program. Talk to your pharmacist about take-back programs in your community. Visit the FDA's Safe Disposal of Medicines website https://goo.gl/c4Rm4p for more information.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Keep all appointments with your doctor and the laboratory. Your doctor may order certain lab tests to check your body's response to doxecitine and doxribtimine.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.

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