Colistimethate is an antibiotic that fights bacteria.

Colistimethate is used to treat infections caused by bacteria.

Colistimethate may also be used for purposes not listed in this medication guide.

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Follow all directions on your prescription label. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Colistimethate is injected into a muscle, or into a vein through an IV. You may be shown how to use injections at home. Do not give yourself this medicine if you do not understand how to use the injection and properly dispose of needles, IV tubing, and other items used.

Colistimethate is a powder medicine that must be mixed with a liquid (diluent) before using it. If you are using the injections at home, be sure you understand how to properly mix and store the medicine.

After mixing colistimethate for injection into a vein (IV infusion), you must use the medicine right away. Do not store for later use.

After mixing colistimethate for injection into a muscle, you may store the mixture in a refrigerator or at cool room temperature. Do not freeze. Use within 7 days.

Colistimethate must be given slowly. Your IV infusion may take 3 to 5 minutes to complete. In some cases, colistimethate is given over a period of up to 23 hours. Follow your doctor's dosing instructions very carefully.

Use this medicine for the full prescribed length of time. Your symptoms may improve before the infection is completely cleared. Skipping doses may also increase your risk of further infection that is resistant to antibiotics. Colistimethate will not treat a viral infection such as the flu or a common cold.

If you need surgery, tell the surgeon ahead of time that you are using colistimethate. You may need to stop using the medicine for a short time.

Store unmixed colistimethate powder at cool room temperature, away from moisture and heat.

Use a disposable needle only once. Follow any state or local laws about throwing away used needles and syringes. Use a puncture-proof "sharps" disposal container (ask your pharmacist where to get one and how to throw it away). Keep this container out of the reach of children and pets.

Usual Adult Dose for Gram Negative Infection:

Parenteral: 2.5 to 5 mg/kg/day IM or IV in 2 to 4 divided doses, depending on severity of infection
Maximum dose: 5 mg/kg/day

Comments:
-The dosage is expressed in terms of colistin base.
-Clinical effectiveness has been shown in the treatment of infections due to Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa.

Approved indication: Treatment of acute or chronic infections due to sensitive strains of certain gram-negative bacilli (particularly infections due to P aeruginosa); not indicated for infections due to Proteus or Neisseria

Some experts recommend:
Inhalation: 50 to 75 mg in normal saline (3 to 4 mL total volume) via nebulizer 2 to 3 times a day

Usual Pediatric Dose for Gram Negative Infection:

Parenteral: 2.5 to 5 mg/kg/day IM or IV in 2 to 4 divided doses, depending on severity of infection
Maximum dose: 5 mg/kg/day

Comments:
-The dosage is expressed in terms of colistin base.
-Clinical effectiveness has been shown in the treatment of infections due to Enterobacter aerogenes, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa.

Approved indication: Treatment of acute or chronic infections due to sensitive strains of certain gram-negative bacilli (particularly infections due to P aeruginosa); not indicated for infections due to Proteus or Neisseria

Some experts recommend:
Inhalation:
Neonates: 4 mg/kg/dose every 12 hours to treat ventilator-associated pneumonia
Infants, children, adolescents: 50 to 75 mg in normal saline (3 to 4 mL total volume) via nebulizer 2 to 3 times a day

You should not use colistimethate if you are allergic to it.

To make sure colistimethate is safe for you, tell your doctor if you have:

• kidney disease.

It is not known whether colistimethate will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It is not known whether colistimethate passes into breast milk or if it could affect the nursing baby. Tell your doctor if you are breast-feeding.

Use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. An overdose of colistimethate can be fatal.

Overdose symptoms may include confusion, dizziness, loss of balance or coordination, severe numbness or tingling, rapid eye movement, problems with speech, weak or shallow breathing, or loss of consciousness.

colistimethate may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Antibiotic medicines can cause diarrhea, which may be a sign of a new infection. If you have diarrhea that is watery or bloody, call your doctor. Do not use anti-diarrhea medicine unless your doctor tells you to.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Colistimethate may cause serious side effects. Call your doctor at once if you have:

• severe stomach pain, diarrhea that is watery or bloody;

• a seizure (convulsions);

• slow breathing;

• unusual muscle weakness;

• fever; or

• kidney problems--little or no urination, painful or difficult urination, swelling in your feet or ankles, feeling tired or short of breath.

Common side effects of colistimethate may include:

• numbness or tingling in your hands, feet, mouth, or tongue;

• slurred speech;

• dizziness, spinning sensation;

• itching, mild rash; or

• upset stomach.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your doctor about all your current medicines and any you start or stop using, especially:

• any injected or IV antibiotics--amikacin, gentamicin, neomycin, polymyxin, streptomycin, tobramycin.

This list is not complete. Other drugs may interact with colistimethate, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.