Ketek
Ketek - General Information
Ketek is a semi-synthetic erythromycin derivative. It is used to treat mild to moderate respiratory infections. Ketek prevents bacteria from growing, by interfering with their protein synthesis. Ketek binds to the subunit 50S of the bacterial ribosome, and blocks the progression of the growing polypeptide chain. In addition, telithromycin binds simultaneously to two domains of 23S RNA of the 50 S ribosomal subunit, where older macrolides bind only to one.
Pharmacology of Ketek
Ketek is a macrolide antibiotic which has an antimicrobial spectrum similar or slightly wider to that of penicillin, and is often used for people who have an allergy to penicillins. For respiratory tract infections, it has better coverage of atypical organisms, including mycoplasma. It is also used to treat outbreaks of chlamydia, syphilis, and gonorrhea. Ketek prevents bacteria from growing, by interfering with their protein synthesis. Ketek binds to the subunit 50S of the bacterial ribosome, and thus inhibits the translocation of peptides.
Ketek for patients
MEDICATION GUIDE
KETEK®
(KEE tek)
Tablets
(telithromycin)
READ THE MEDICATION GUIDE THAT COMES WITH KETEK BEFORE YOU START TAKING IT. TALK TO YOUR DOCTOR IF YOU HAVE ANY QUESTIONS ABOUT KETEK. THIS MEDICATION GUIDE DOES NOT TAKE THE PLACE OF TALKING WITH YOUR DOCTOR ABOUT YOUR MEDICAL CONDITION OR TREATMENT.
WHAT IS THE MOST IMPORTANT INFORMATION I SHOULD KNOW ABOUT KETEK?
1. Do not take KETEK if you have Myasthenia Gravis (a rare disease which causes muscle weakness). Worsening of myasthenia gravis symptoms including life-threatening breathing problems have happened in patients with myasthenia gravis after taking KETEK in some cases leading to death.
KETEK can cause other serious side effects, including:
2. SEVERE LIVER DAMAGE (HEPATOXICITY). SEVERE LIVER DAMAGE, IN SOME CASES LEADING TO A LIVER TRANSPLANT OR DEATH HAS HAPPENED IN PATIENTS TREATED WITH KETEK. SEVERE LIVER DAMAGE HAS HAPPENED DURING TREATMENT, EVEN AFTER A FEW DOSES, OR RIGHT AFTER TREATMENT WITH KETEK HAS ENDED.
Stop KETEK and call your doctor right away if you have signs of liver problems. Do not take another dose of KETEK unless your doctor tells you to do so.
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Signs of liver problems include: • increased tiredness • loss of appetite • yellowing of the skin and/or eyes • right upper belly pain |
• light-colored stools • dark urine • itchy skin |
Do not take KETEK if you have ever had side effects of the liver while taking KETEK or macrolide antibiotics. Macrolide antibiotics include erythromycin, azithromycin (Zithromax®), clarithromycin (Biaxin®) or dirithromycin (Dynabac®).
3. Vision problems. KETEK may cause blurred vision, trouble focusing, and double vision. You may notice vision problems if you look quickly from near objects to far objects.
4. Fainting. You may faint especially if you are also having nausea, vomiting, and lightheadedness.
- BE AWARE THAT VISION PROBLEMS AND FAINTING WHILE TAKING KETEK MAY AFFECT YOUR ABILITY TO DRIVE OR DO DANGEROUS ACTIVITIES. LIMIT DRIVING AND OTHER DANGEROUS ACTIVITIES.
- IF YOU HAVE VISION PROBLEMS OR FAINT WHILE TAKING KETEK
- DO NOT DRIVE, OPERATE HEAVY MACHINES, OR DO DANGEROUS ACTIVITIES.
- CALL YOUR DOCTOR BEFORE TAKING ANOTHER DOSE OF KETEK IF YOU HAVE VISION PROBLEMS OR FAINT.
See "What are the possible side effects of KETEK? for other side effects of KETEK.
WHAT IS KETEK?
KETEK is an antibiotic. KETEK is used to treat adults 18 years of age and older with a lung infection called "community acquired pneumonia" that is caused by certain bacteria germs.
- KETEK is not for other types of infections caused by bacteria
- KETEK, like other antibiotics, does not kill viruses.
WHO SHOULD NOT TAKE KETEK?
Do not take KETEK if you:
- have myasthenia gravis
- have had side effects on the liver while taking KETEK or macrolide antibiotics.
- have ever had an allergic reaction to KETEK or macrolide antibiotics.
- take cisapride (Propulsid®) or pimozide (Orap®).
KETEK may not be right for you. Before taking KETEK, tell your doctor about all of your medical conditions, including if you:
- have myasthenia gravis
- have liver problems
- have (or have a family history of) a heart problem called "QTc prolongation"
- have other heart problems
- are pregnant or breastfeeding
Tell your doctor about all of the medicines you take, including prescription and nonprescription medicines, vitamins, and herbal supplements. KETEK and other medicines may affect or interact with each other, sometimes causing serious side effects.
You should not take the following cholesterol lowering medicines while taking KETEK:
- simvastatin (Zocor®, Vytorin®)
- lovastatin (Mevacor®)
- atorvastation (Lipitor®)
Know the medicines you take. Keep a list of your medicines with you to show your doctor or pharmacist.
Do not take other medicines with KETEK without first checking with your doctor. Your doctor will tell you if you can take other medicines with KETEK.
HOW SHOULD I TAKE KETEK?
- Take KETEK exactly as your doctor tells you. Skipping doses or not taking
all of an antibiotic may:
- make the treatment not work as well
- increase the chance that the bacteria will develop resistance to the antibiotic
- The usual dose is two 400 mg KETEK Tablets taken at the same time once a day for 7 to 10 days. If you have kidney disease, your doctor may prescribe a lower dose for you.
- Take KETEK with or without food.
- Swallow KETEK tablets whole.
- Call your doctor if you took too much KETEK.
WHAT ARE THE POSSIBLE SIDE EFFECTS OF KETEK?
See "What is the most important information I should know about KETEK?" for worsening of myasthenia gravis symptoms, and serious liver, vision, and fainting side effects.
Other serious side effects include:
- Pseudomembranous colitis (an intestine infection). Pseudomembranous colitis can happen with most antibiotics, including KETEK. Call your doctor if you get watery diarrhea, diarrhea that does not go away, or bloody stools. You may also have stomach cramps and a fever. Pseudomembranous colitis can happen up to 2 months after you have finished your antibiotic.
The most common side effects of KETEK are nausea, headache, dizziness, vomiting, and diarrhea.
These are not all of the side effects of KETEK. Ask your doctor or pharmacist for more information.
HOW SHOULD I STORE KETEK?
- Store KETEK tablets at room temperature, 59° to 86°F (15° to 30°C).
- Keep KETEK and all medicines out of the reach of children.
GENERAL INFORMATION ABOUT KETEK
- Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide.
- Do not use KETEK for a condition for which it was not prescribed.
- Do not share KETEK with other people, even if they have the same symptoms that you have. It may harm them.
This Medication Guide summarizes the most important information about KETEK. If you would like more information, talk with your doctor. You can ask your doctor or pharmacist for information about KETEK that was written for healthcare professional. This information is also available on the KETEK website at www.KETEK.com.
What are the ingredients in KETEK?
Active Ingredient: telithromycin
Inactive Ingredients: croscarmellose sodium, hypromellose, magnesium stearate, microcrystalline cellulose, polyethylene glycol, povidone, red ferric oxide, talc, titanium dioxide, and yellow ferric oxide
Ketek Interactions
Telithromycin is a strong inhibitor of the cytochrome P450 3A4 system. Co-administration of Telithromycin tablets and a drug primarily metabolized by the cytochrome P450 3A4 enzyme system may result in increased plasma concentration of the drug co-administered with telithromycin that could increase or prolong both the therapeutic and adverse effects. Therefore, appropriate dosage adjustments may be necessary for the drug co-administered with telithromycin.
The use of Telithromycin is contraindicated with cisapride.
The use of Telithromycin is contraindicated with pimozide. Although there are no studies looking at the interaction between Telithromycin and pimozide, there is a potential risk of increased pimozide plasma levels by inhibition of CYP 3A4 pathways by Telithromycin as with macrolides.
In a pharmacokinetic study, simvastatin levels were increased due to CYP 3A4 inhibition by telithromycin. Similarly, an interaction may occur with lovastatin or atorvastatin, but not with pravastatin or fluvastatin. High levels of HMG-CoA reductase inhibitors increase the risk of myopathy. Use of simvastatin, lovastatin, or atorvastatin concomitantly with Telithromycin should be avoided. If Telithromycin is prescribed, therapy with simvastatin, lovastatin, or atorvastatin should be suspended during the course of treatment.
Monitoring of digoxin side effects or serum levels should be considered during concomitant administration of digoxin and Telithromycin.
Patients should be monitored with concomitant administration of midazolam and dosage adjustment of midazolam should be considered if necessary. Precaution should be used with other benzodiazepines, which are metabolized by CYP 3A4 and undergo a high first-pass effect (e.g., triazolam).
Concomitant treatment of Telithromycin with rifampin, a CYP 3A4 inducer, should be avoided. Concomitant administration of other CYP 3A4 inducers such as phenytoin, carbamazepine, or phenobarbital is likely to result in subtherapeutic levels of telithromycin and loss of effect.
In patients treated with metoprolol for heart failure, the increased exposure to metoprolol, a CYP 2D6 substrate, may be of clinical importance. Therefore, co-administration of Telithromycin and metoprolol in patients with heart failure should be considered with caution.
Spontaneous post-marketing reports suggest that administration of Telithromycin and oral anticoagulants concomitantly may potentiate the effects of the oral anticoagulants. Consideration should be given to monitoring prothrombin times/INR while patients are receiving Telithromycin and oral anticoagulants simultaneously.
No specific drug interaction studies have been performed to evaluate the following potential drug-drug interactions with Telithromycin. However, these drug interactions have been observed with macrolide products.
Drugs metabolized by the cytochrome P450 system such as carbamazepine, cyclosporine, tacrolimus, sirolimus, hexobarbital, and phenytoin: elevation of serum levels of these drugs may be observed when co-administered with telithromycin. As a result, increases or prolongation of the therapeutic and/or adverse effects of the concomitant drug may be observed.
Ergot alkaloid derivatives (such as ergotamine or dihydroergotamine): acute ergot toxicity characterized by severe peripheral vasospasm and dysesthesia has been reported when macrolide antibiotics were co-administered. Without further data, the co-administration of Telithromycin and these drugs is not recommended.
Laboratory test interactions
There are no reported laboratory test interactions.
Ketek Contraindications
Telithromycin is contraindicated in patients with a history of hypersensitivity to telithromycin and/or any components of Telithromycin tablets, or any macrolide antibiotic. Concomitant administration of Telithromycin with cisapride or pimozide is contraindicated.
Additional information about Ketek
Ketek Indication: For the treatment of Pneumococcal infection, acute sinusitis, acute bacterial tonsillitis, acute bronchitis and bronchiolitis, lower respiratory tract infection and lobar (pneumococcal) pneumonia.
Mechanism Of Action: Ketek acts by binding to domains II and V of 23S rRNA of the 50S ribosomal subunit. By binding at domain II, telithromycin retains activity against gram-positive cocci (e.g., Streptococcus pneumoniae) in the presence of resistance mediated by methylases (erm genes) that alter the domain V binding site of telithromycin. Ketek may also inhibit the assembly of nascent ribosomal units.
Drug Interactions: Not Available
Food Interactions: Not Available
Generic Name: Telithromycin
Synonyms: Not Available
Drug Category: Anti-Bacterial Agents; Ketolides
Drug Type: Small Molecule; Approved; Investigational
Other Brand Names containing Telithromycin: Ketek;
Absorption: Not Available
Toxicity (Overdose): LD50>2000 mg/kg (PO in rats)
Protein Binding: 60%-70%
Biotransformation: Hepatic
Half Life: 10 hours
Dosage Forms of Ketek: Tablet Oral
Chemical IUPAC Name: (1R,2R,4R,6S,7R,8R,10R,13R,14S)-7-[(2S,3R,4S,6R)-4-dimethylamino-3-hydroxy-6-methyloxan-2-yl]oxy-13-ethyl-6-methoxy-2,4,6,8,10,14-hexamethyl-17-[4-(4-pyridin-3-ylimidazol-1-yl)butyl]-12,15-dioxa-17-azabicyclo[12.3.0]heptadecane-3,9,11,16-tetrone
Chemical Formula: C43H65N5O10
Telithromycin on Wikipedia: https://en.wikipedia.org/wiki/Telithromycin
Organisms Affected: Enteric bacteria and other eubacteria