Systematic (IUPAC) name | |
---|---|
1-cyclopropyl-7-[(1S,6S)-2,8-diazabicyclo
[4.3.0]non-8-yl]-6-fluoro-8-methoxy-4-oxo- quinoline-3-carboxylic acid |
|
Identifiers | |
CAS number | 354812-41-2 |
ATC code | J01MA14 S01AX22 |
PubChem | CID 152946 |
DrugBank | APRD00281 |
ChemSpider | 134802 |
Chemical data | |
Formula | C21H24FN3O4 |
Mol. mass | 401.431 g/mol |
SMILES | eMolecules & PubChem |
Pharmacokinetic data | |
Bioavailability | 86 to 92% |
Protein binding | 30 to 50% |
Metabolism | Glucuronide and sulfate conjugation Cytochrome P450 system not involved |
Half-life | 12 hours |
Excretion | hepatic |
Therapeutic considerations | |
Pregnancy cat. | C (US) B3 (Australia) |
Legal status | Prescription Only |
Routes | Oral, IV, local (eyedrops) |
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Moxifloxacin is a fourth generation synthetic fluoroquinolone antibacterial agent developed by Bayer AG (initially called BAY 12-8039). It is marketed worldwide (as the hydrochloride) under the brand names Avelox, Avalox and Avelon for oral treatment. In most countries the drug is also available in parenteral form for intravenous infusion. Moxifloxacin is also sold in an ophthalmic solution (eye drops) under the brand name Vigamox for the treatment of conjunctivitis (pink eye).
A United States patent application was submitted on June 30, 1989 for Avelox (moxifloxacin hydrochloride)[1], but it was not until 1999 (ten years later) that Avelox was approved by the U.S. Food and Drug Administration (FDA) for use in the United States to treat severe and life threatening bacterial infections.[2]
The licensed uses for moxifloxacin are quite limited as moxifloxacin is to be considered a drug of last resort when all other antibiotics have failed.[3] There are currently only six approved uses in the adult population (three of which are restricted[4]) and Vigamox (ophthalmic) is the only one used for children. Moxifloxacin interacts with a number of other drugs, as well as a number of herbal and natural supplements.[5]
Avelox (moxifloxacin) was launched in the United States in 1999 and is currently marketed in more than 80 countries worldwide. In the United States Avelox is marketed by Bayer’s partner, Schering-Plough Corporation. Within the past year (2008–2009) Bayer has issued three Dear Doctor Letters concerning severe adverse reactions associated with the use of moxifloxacin, as well as giving notice regarding restrictions in its use.[4][6][7] First marketed in 1999, moxifloxacin is Bayer's heir apparent to ciprofloxacin.
Moxifloxacin was first patented (United States patent) in 1991[1] by Bayer A.G., and again in 1997.[8] Avelox was subsequently approved by the U.S. Food and Drug Administration (FDA) for use in the United States in 1999 to treat specific bacterial infections.[2] Ranking 140th within the top 200 prescribed drugs in the United States for 2007[9] moxifloxacin, in the same manner as ciprofloxacin, has proven to be a blockbuster drug for Bayer A. G., generating billions of dollars in additional revenue. In 2007 alone, Avelox generated sales of $697.3 million dollars worldwide.[10]
However, there were serious questions raised within the NDA (New Drug Application, 1999) regarding the safety and efficacy of moxifloxacin, which now appears to threaten its continuing viability. Of particular concern is moxifloxacin induced cardiac arrhythmias. The Medical Review Officer stated that “Moxifloxacin clearly prolongs QTc intervals in a concentration-related manner and as a result puts patients at risk for developing malignant arrhythmias. The data provided by the sponsor did not include all patients treated, about 90% were excluded, and ECG were obtained as late as 6 hours after the drug intake (peak concentration is about 2 hours). So the sponsor’s argument that moxifloxacin is safe because it only causes a small increase in QTc is flawed. What was shown in the database is that there are examples of patients on moxifloxacin with changes in QTc intervals greater than 80 msec over baseline with resulting QTc intervals above 500 msec.... Moxifloxacin raises the QTc interval in a concentration related manner and therefore has the potential to cause malignant ventricular arrhythmias, including torsade de pointes, and death.... In summary, it is hard to justify approving this agent as a first line therapy for non-life threatening infections in which there are a plethora of treatment choices.(sic)”[11] The FDA approved moxifloxacin over the objections of the members of the FDA advisory committee,[12] as well as the medical review officer (noted above), even though the studies submitted with the NDA failed to show any advantage over the comprators presented in a number of instances.
Since the approval of moxifloxacin in 1999, there has been numerous upgrades to the warnings sections of the package inserts, as well as three Dear Doctor Letters issued by the manufacturer over the past year.[4][6][7] The latest involving the very issues raised with the NDA, ten years ago. Within the 2009 “Rote-Hand-Brief” German officials warned German physicians of the associated risk of cardiac arrhythmia in women and older patients.[4] At its July 2008 meeting, the agency's Committee for Medicinal Products for Human Use (CHMP) recommended restricting the use of moxifloxacin due to safety concerns, mainly related to an increased risk of adverse hepatic reactions.[10]
Never the less moxifloxacin continues to be aggressively marketed by Bayer. Bayer makes about $500 million a year from moxifloxacin, which it sells in the United States as Avelox and elsewhere as Avalox, Avelon, Megaxin, Actira and Izilox.[13]
A United States patent application was made on June 30, 1989 for Avelox (moxifloxacin hydrochloride)[1], (Bayer A.G. being the assignee), which was subsequently approved on February 5, 1991. This patent was scheduled to expire on June 30, 2009. However, this patent was extended for an additional two and one half years on September 16, 2004, and as such is not expected to expire until 2012.[14] Moxifloxacin was subsequently (ten years later) approved by the U.S. Food and Drug Administration (FDA) for use in the United States in 1999. There have been at least four additional United States patents filed regarding moxifloxacin hydrochloride since the 1989 United States application,[8][15] as well as patents outside of the USA.
The intravenous preparation is not licensed for use in the UK. The licensed uses for Oral and I.V. moxifloxacin in the United States are as follows:
In the adult population Oral and I.V. moxifloxacin is limited to the treatment of proven serious and life threatening bacterial infections. The initial approval by the FDA (December 1999)[16] encompassed the following indications:
Additional indications were approved by the FDA as follows:
The licensed uses noted as restricted use requires that moxifloxacin only be prescribed when other antibiotics that have been initially recommended for treatment cannot be used or have failed.[3][4][23]
Currently there are no approved uses within the pediatric population for Oral and I.V. moxifloxacin. A significant number of drugs found within this class, including moxifloxacin, are not licensed by the FDA for use in children due to the risk of fatalities[24][25] as well as permanent injury to the musculoskeletal system.[26]
Prescribing moxifloxacin to treat an unapproved use (other than those listed above) within the pediatric, as well as the adult population, does however take place rather frequently.
In ophthalmology, moxifloxacin licensed use is limited to the treatment of conjunctival infections caused by susceptible bacteria.[27]
Note: Moxifloxacin may be licensed for other uses, or restricted, by the various regulatory agencies worldwide.
Moxifloxacin is available as:
See the latest package insert for Moxifloxacin (Avelox) for additional details.
Moxifloxacin is a broad-spectrum antibiotic that is active against both Gram-positive and Gram-negative bacteria. It functions by inhibiting DNA gyrase, a type II topoisomerase, and topoisomerase IV,[28] enzymes necessary to separate bacterial DNA, thereby inhibiting cell replication.
This mechanism can also affect mammalian cell replication. In particular, some congeners of this drug family (for example those that contain the C-8 fluorine),[29] display high activity not only against bacterial topoisomerases, but also against eukaryotic topoisomerases and are toxic to cultured mammalian cells and in vivo tumor models.[30] Although quinolones are highly toxic to mammalian cells in culture, its mechanism of cytotoxic action is not known. Quinolone induced DNA damage was first reported in 1986 (Hussy et al.).[31]
Recent studies have demonstrated a correlation between mammalian cell cytotoxicity of the quinolones and the induction of micronuclei.[32][33][34][35] As such some fluoroquinolones, including moxifloxacin, may cause injury to the chromosome of eukaryotic cells.[36][37][38][39][40][41]
There continues to be considerable debate as to whether or not this DNA damage is to be considered one of the mechanisms of action concerning the severe adverse reactions experienced by some patients following fluoroquinolone therapy.[30][42][43]
The fluoroquinolone class is now considered to be contraindicated for the treatment of certain sexually transmitted diseases by some experts due to bacterial resistance.[44] Due to growing prevalence of antibiotic resistance to the fluoroquinolones in southeast Asia, the use of the drugs found within the fluoroquinolone class (which would include moxifloxacin) in patients who have been to southeast Asia is increasingly being contraindicated.[44][45]
There are only two listed contraindications found within the 2008 package insert:
Though not stated as such within the package insert ziprasidone is also considered to be contraindicated as it may have the potential to prolong QT interval. Moxifloxacin should also be avoided in patients with uncorrected hypokalemia, or concurrent administration of other medications known to prolong the QT interval (antipsychotics and tricyclic antidepressants).[47]
Moxifloxacin should be used with caution in patients suffering from diabetes as glucose regulation may be significantly altered.[47]
Moxifloxacin is also considered to be contraindicated within the pediatric population, pregnancy, nursing mothers, patients with a history of tendon disorder, patients with documented QT prolongation[7] and in patients with epilepsy or other seizure disorders. Coadministration of moxifloxacin with other drugs that also prolong the QT interval or induce bradycardia (eg, beta-blockers, amiodarone) should be avoided. Careful consideration should be given in the use of moxifloxacin in patients with cardiovascular disease, including those with conduction abnormalities.[47]
Recently (2008) Bayer issued a Europrean Dear Doctor Letter concerning moxifloxacin associated liver damage and as such the use of moxifloxacin would now be considered contraindicated in patients who have impaired liver function.[4]
The fluoroquinolones rapidly cross the blood-placenta and blood-milk barrier, and are extensively distributed into the fetal tissues. For this reason the fluroquinolones are contraindicated during pregnancy due to the risk of spontaneous abortions and birth defects. The flouroquinolones have also been reported as being present in the mother’s milk and are passed on to the nursing child, which may increases the risk of the child suffering from this syndrome as well, even though the child had never been prescribed or taken any of the drugs found within this class.[48][49]
Fluoroquinolones are not licensed by the FDA for use in children due to the risk of fatalities[25] as well as permanent injury to the musculoskeletal system, with two exceptions. Ciprofloxacin is being licensed for the treatment of Complicated Urinary Tract Infections and Pyelonephritis due to Escherichia coli and Inhalational Anthrax (post-exposure) and Levofloxacin was recently licensed for the treatment of Inhalational Anthrax (post-exposure). However, the fluoroquinolones are licensed to treat lower respiratory infections in children with cystic fibrosis in the UK. It does not appear that there have been any pediatric trials involving oral or IV moxifloxacin to date. But the fluoroquinolones that have been involved in pediatric clinical trials reveal the following:
Within one study it was stated that the pediatric patient has a 3.8% chance of experiencing a serious musculoskeletal adverse event.[50] Within the studies submitted in response to a Pediatric Written Request (Ciprofloxacin, circa 2004) the rate of athropy was reported to be 9.3%.[51]
Two recent pediatric studies involving the use of levofloxacin indicates that the pediatric patient has a greater than 50% chance of experiencing one or more adverse reactions. Which would be consistent with the studies found within the NDA (new drug application) for Levofloxacin[52] which showed and ADR rate in excess of 40%, as well as a number of reported fatalities. Within the first study[24] it is stated that “Of the 712 subjects evaluable for safety, 275 (52%) levofloxacin-treated subjects experienced one or more adverse event... Serious adverse events were reported in 33 (6%) levofloxacin-treated subjects... Two serious adverse events in levofloxacin-treated subjects resulted in fatal outcomes.” Within the second study[53] it is stated that “Of the 204 subjects evaluable for safety, 122 experienced one or more adverse events.... Twelve subjects (6%) discontinued study drug due to an adverse event.... Seven subjects (3%) experienced 8 serious adverse events'.” (circa 2007)
Within the BPCA Pediatric Studies Summary for ciprofloxacin[51] it was stated that the overall incidence of adverse events at six weeks was 41%. This would be consistent with the safety profile found with the other fluoroquinolones studied in the pediatric population, as noted above with levofloxacin. As such the current ban on the use of the fluoroquinolones in the pediatric population is both reasonable and supported by various clinical studies. The risk of permanent injury outweighs the potential benefits.
The serious adverse effects that may occur as a result of moxifloxacin therapy include irreversible peripheral neuropathy, spontaneous tendon rupture and tendonitis,[54] acute liver failure or serious liver injury, QTc prolongation/torsades de pointes, toxic epidermal necrolysis (TEN) and clostridium difficile associated disease (CDAD),[55] as well as photosensitivity/phototoxicity reactions.[56] Hepatitis, pseudomembranous colitis, psychotic reactions and Stevens-Johnson syndrome have also been associated with moxifloxacin therapy.[57]
There has been a number of regulatory actions taken as a result of such adverse reactions, which included published warnings,[58] the issuance of numerous "Dear Doctor Letters",[4][6][7][59] the restrictions regarding the use of moxifloxacin instituted by the European agency's Committee for Medicinal Products for Human Use (CHMP),[10] as well as the recent addition of Black Box Warnings.[60] On March 22, 2010 Health Canada issued a notice to health care professionals and Canadians regarding the recent changes to the labeling information for Avelox (moxifloxacin). The 2010 Canadian updated labeling now includes information regarding the risk of severe liver injury taking place during moxifloxacin therapy.[61]
These serious events may occur with therapeutic or with acute overdose. Such adverse reactions may manifest during, as well as after moxifloxacin therapy.[62]
Most recently the German regulatory authorities placed additional restrictions on the use of oral moxifloxacin in patients with acute bacterial sinusitis (ABS), acute exacerbation of chronic bronchitis (AECB) and community-acquired pneumonia (CAP) stating that in case of these diseases moxifloxacin should only be prescribed when other antibiotics that have been initially recommended for treatment cannot be used or have failed. Additional notice was given that rhabdomyolysis, the exacerbation of symptoms of myasthenia gravis and the risk of cardiac arrhythmia in women and older patients, was associated with moxifloxacin.[7] Currently the German regulatory authorities are investigating the association of severe and life threatening QTc prolongation/torsades de pointes with moxifloxacin therapy, which the FDA had raised serious concerns about during the initial drug approval process back in 1999.[63][64][65]
Serious visual complications have also been reported to occur with ophthalmic fluoroquinolone therapy, which may also occur with Vigamox, especially corneal perforation, but also evisceration and enucleation. Corneal perforation occurred most commonly in elderly patients with deep ulcers. This increased incidents of corneal perforation may be due to fluoroquinolones causing alterations in stromal collagen, leading to a reduction in tectonic strength.[66][67]
Antacids containing aluminium or magnesium ions inhibit the absorption of moxifloxacin. Drugs that prolong the QT interval (e.g., pimozide) may have an additive effect on QT prolongation and lead to increased risk of ventricular arrhythmias. The INR (International Normalised Ratio) may be increased or decreased in patients treated with warfarin. Moxifloxacin has been shown in a number of case reports to interact with warfarin.[68] The exact mechanism for the warfarin-quinolone drug interaction is unknown.[69] A precautionary measure would be to monitor the INR more closely and, if necessary, adjust the anticoagulant dose as necessary. Moxifloxacin does not appear to inhibit theophylline metabolism.[70] However, caution may be warranted when using theophylline with all of the fluoroquinolones, including moxifloxacin. Drug Interaction Facts notes that some fluoroquinolones, especially ciprofloxacin, enoxacin, and norfloxacin interact with theophylline.[69]
Moxifloxacin is not believed to be associated with clinically significant drug interactions due to inhibition or stimulation of hepatic metabolism. Thus it should not, for the most part, require special clinical or laboratory monitoring to ensure its safety.[71] However there is an additive effect of moxifloxacin and drugs that prolong the QT interval, such as cisapride, erythromycin, antipsychotics and tricyclic antidepressants. Therefore moxifloxacin should be used with caution when given concurrently with such drugs. Moxifloxacin also has a potential for a serious drug interaction with NSAIDS. Additionally the package insert cautions that prothrombin time should be closely monitored if moxifloxacin is concomitantly administered with warfarin.[72]
A potentially serious drug interaction is the combination of corticosteroids and moxifloxacin, as this combination increases tendon toxicity which can potentially result in tendonitis and disability.[73]
"In the event of acute overdose, the stomach should be emptied and adequate hydration maintained. ECG monitoring is recommended due to the possibility of QT interval prolongation. The patient should be carefully observed and given supportive treatment. The administration of activated charcoal as soon as possible after oral overdose may prevent excessive increase of systemic moxifloxacin exposure. About 3% and 9% of the dose of moxifloxacin, as well as about 2% and 4.5% of its glucuronide metabolite are removed by continuous ambulatory peritoneal dialysis and hemodialysis, respectively."(sic) Quoting from the 12/29/2008 package insert for Avelox [46]
"Moxifloxacin, a fluoroquinolone, is available as the monohydrochloride salt of 13 1-cyclopropyl-7-[(S,S)-2,8-diazabicyclo[4.3.0]non-8-yl]-6-fluoro-8-methoxy-1,4-dihydro-4-oxo-3 14 quinoline carboxylic acid. It is a slightly yellow to yellow crystalline substance with a molecular 15 weight of 437.9. Its empirical formula is C21H24FN3O4 *HCl." Quoting from the 12/29/2008 package insert for Avelox [46]
There are a number of the endogenous compounds that have been reported to be affected by moxifloxacin as inhibitors, alteraters and depletors. See the latest package insert for Ciprofloxacin for additional details.
Approximately 52% of an oral or intravenous dose of moxifloxacin is metabolized via glucuronide and sulfate conjugation. The cytochrome P450 system is not involved in moxifloxacin metabolism, and is not affected by moxifloxacin. The sulfate conjugate (M1) accounts for approximately 38% of the dose, and is eliminated primarily in the feces. Approximately 14% of an oral or intravenous dose is converted to a glucuronide conjugate (M2), which is excreted exclusively in the urine. Peak plasma concentrations of M2 are approximately 40% those of the parent drug, while plasma concentrations of M1 are generally less than 10% those of moxifloxacin.[46]
In vitro studies with cytochrome (CYP) P450 enzymes indicate that moxifloxacin does not inhibit 80 CYP3A4, CYP2D6, CYP2C9, CYP2C19, or CYP1A2, suggesting that moxifloxacin is unlikely to alter the pharmacokinetics of drugs metabolized by these enzymes.[46]
The pharmacokinetics of moxifloxacin in pediatric subjects have not been studied.[46]
The half life of moxifloxacin is 11.5-15.6 hours (single dose, oral).[74] Approximately 45% of an oral or intravenous dose of moxifloxacin is excreted as unchanged drug (~20% in urine and ~25% in feces). A total of 96% ± 4% of an oral dose is excreted as either unchanged drug or known metabolites. The mean (± SD) apparent total body clearance and renal clearance are 12 ± 2 L/hr and 2.6 ± 0.5 L/hr, respectively.[74] The CSF penetration of moxifloxacin is 70 to 80% in patients with meningitis.[75]
Moxifloxacin should only be administered as described within the Dosage Guidelines table found within the most current package insert. The status of the patient’s renal function and hepatic function must also be taken into consideration to avoid an accumulation that may lead to a fatal drug overdose. Moxifloxacin is eliminated primarily by renal excretion. However, the drug is also metabolized and partially cleared through the liver and the intestine. Modification of the dosage is recommended using the table found within the package insert for those with impaired kidney function. (Particularly for patients with severe renal dysfunction.) No dosage adjustment is recommended by the manufacturer for mild, moderate, or severe hepatic insufficiency (Child-Pugh Classes A, B, or C). However, due to metabolic disturbances associated with hepatic insufficiency, which may lead to QT prolongation, moxifloxacin should be used with caution in these patients. However, since the drug is known to be substantially excreted by the kidneys, the risk of toxic reactions to this drug may be greater in patients with impaired renal function. The standard dose of moxifloxacin is 400 mg (orally or as an intravenous infusion) once every 24 hours. The duration of treatment depends upon the severity of infection and the usual duration is 7 to 14 days.
NOTE: The patient’s serum levels should be monitored during therapy to avoid a drug overdose. See the most current Package Insert for proper dosing guidelines and relevant warnings/precautions.
A broad spectrum of bacteria is susceptible including, but not limited to:
6/12/2002 Changes made to minimize the impact of warnings concerning adverse reactions.[76]
6/26/2003 New Zealand Pharmacovigilance warns of moxifloxacin induced respiratory insufficiency.[77]
10/6/2003 Changes made to minimize the impact of post marketing reports as well as the risk of tendon injuries.[78]
12/29/2008 Addition of numerous adverse reactions associated with the use of moxifloxacin.[79]
04/27/2009 Issuance of a Medication Guide and revisions to include new safety information including the addition of the Black Box Warning to the Medication Guide. The FDA had determined that Moxifloxacin poses a serious and significant public health concern, requiring the distribution of a Medication Guide.[80]
06/24/2009 Updating of the carton and container labels to include a statement to let dispensers know that a Medication Guide must be dispensed with the product.(emphasis added)[81]
Musculoskeletal disorders attributed to use of quinolone antibiotics were first reported in the medical literature in 1972, as an adverse reaction to nalidixic acid.[82] Rheumatic disease after use of a fluoroquinolone (norfloxacin) was first reported eleven years later.[83] In a 1995 letter published in the New England Journal of Medicine, representatives of the U.S. Food and Drug Administration (FDA) stated that the agency would "update the labeling [package insert] for all marketed fluoroquinolones to include a warning about the possibility of tendon rupture."[84]
By August 1996, the FDA had not taken action, and the consumer advocacy group Public Citizen filed a petition with the FDA prompting the agency to act.[85] Two months later, the FDA published an alert in the FDA Medical Bulletin and requested that fluoroquinolone package inserts be amended to include information on this risk.[86]
In 2005, the Illinois Attorney General filed a petition with the FDA seeking black box warnings and "Dear Doctor" letters emphasizing the risk of tendon rupture; the FDA responded that it had not yet been able to reach a decision on the matter.[87] In 2006, Public Citizen, supported by the Illinois Attorney General, renewed its demand of ten years prior for a black box warning.[87][88] In January 2008, Public Citizen filed suit to compel the FDA to respond to their 2006 petition.[89][90] On July 7, the FDA ordered the makers of systemic-use fluoroquinolones to add a boxed warning regarding tendon rupture, and to develop a Medication Guide for patients.[91] The package inserts for Cipro (ciprofloxacin), Avelox (moxifloxacin), Proquin XR, Factive (gemifloxacin), Floxin (ofloxacin), Noroxin (norfloxacin) and Levaquin (levofloxacin) were amended on September 8, 2008 to include these new warnings.[92][93] Bayer, which manufactures Cipro, Avelox and Proquin XR, issued a Dear Healthcare Professional letter on October 22 concerning these changes.[94] Ortho-McNeil, the manufacturers of Levaquin, issued a similar letter in November.[95] through the Health Care Notification Network, a registration-only website that distributes drug alerts to licensed healthcare professionals.
Review of the FDA website indicates that the generic versions of the fluoroquinolones have not been updated to include this Black Box Warning as of February 2009. And there are numerous reports that this information has not been dessiminated to the pharmacist, the products continue to contain the previous labels that are absent of this warning, and the Medication Guide has not been made available to the pharmicist or physician for distribution.
The manufacturers of Avelox (moxiflocaxin – Bayer A. G.) have received warning letters from the FDA regarding false advertising, promotion of unapproved uses and failure to provide adequate warnings within their promotional materials:
December 15, 1999 Lack of fair balance and presentation of misleading safety information, promotion of unapproved uses, unsubstantiated superiority claims.[96]
June 21, 2001 Promotion of unapproved uses.[97]
Resistance to moxifloxacin and other fluoroquinolones may evolve rapidly, even during a course of treatment. Numerous pathogens, including Staphylococcus aureus, enterococci, and Streptococcus pyogenes now exhibit resistance worldwide.[98] Widespread veterinary usage of the fluoroquinolones, in particular in Europe, has been implicated.[99]
The ever increasing bacterial resistance to moxifloxacin, (which is a major concern) together with an unacceptable safety profile, may very well threaten its future viability to treat serious and life threatening bacterial infections. Years ago the FDA had added warnings regarding the proper use of these drugs within the package inserts to combat such antibiotic abuse. Advising physicians that moxifloxacin: "...should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria....'"(See the monographs for this class)
Normally moxifloxacin and other fluoroquinolone drugs would only be used in patients who have failed at least one prior therapy. Reserved for the use in patients who are seriously ill and may soon require immediate hospitalization.[100] Though considered to be a very important and necessary drug required to treat severe and life threatening bacterial infections, the associated scripting abuse of moxifloxacin remains unchecked, which has contributed to the problem of bacterial resistance. The overuse of antibiotics such as happens with children suffering from otitis media has given rise to a breed of super bacteria which are resistant to antibiotics entirely.[101]
For example the use of the fuoroquinolones had increased three-fold in an emergency room environment in the United States between 1995 and 2002, while the use of safer alternatives such as macrolides declined significantly.[102][103]
Fluoroquinolones had become the most commonly prescribed class of antibiotics to adults in 2002. Nearly half (42%) of these prescriptions were for conditions not approved by the FDA, such as acute bronchitis, otitis media, and acute upper respiratory tract infection, according to a study that was supported in part by the Agency for Healthcare Research and Quality.[103][104] Additionally they are commonly prescribed for medical conditions that are not even bacterial to begin, with such as viral infections, or those to which no proven benefit exist.
Resistance to moxifloxacin arises in Mycobacterium tuberculosis if moxifloxacin is used alone instead of in combination with other anti-TB drugs,[105] and this appears to be the explanation for the appearance of moxifloxacin resistance in newly diagnosed TB patients in Baltimore[106] and in Taiwan.[107] Of concern is that the development of resistance can appear in as short a time as seven days.[107] This calls into question the first line use of moxifloxacin and other respiratory quinolones as first line therapy for the treatment of community-acquired pneumonia in populations where TB is still endemic.
In 2007, the U.S. District Court for the District of Delaware held that two Bayer patents on Avelox (moxifloxacin hydrochloride) are valid and enforceable, and infringed by Dr. Reddy's ANDA for a generic version of Avelox.[108][109] The district court sided with Bayer, citing the Federal Circuit's prior decision in Takeda v. Alphapharm [110] as "affirming the district court's finding that defendant failed to prove a prima facie case of obviousness where the prior art disclosed a broad selection of compounds, any one of which could have been selected as a lead compound for further investigation, and defendant did not prove that the prior art would have led to the selection of the particular compound singled out by defendant." According to Bayer’s press release[108] announcing the court’s decision, it was noted that Teva had also challenged the validity of the same Bayer patents at issue in the Dr. Reddy's case. Within Bayer’s first quarter 2008 stockholder’s newsletter[111] Bayer stated that they had reached an agreement with Teva Pharmaceuticals USA, Inc., the adverse party, to settle their patent litigation with regard to the two Bayer patents. Under the settlement terms agreed upon, Teva would obtain a license to sell its generic moxifloxacin tablet product in the U.S. shortly before the second of the two Bayer patents expires in March 2014.
The adverse drug reaction profile of moxifloxacin and other fluoroquinolone drugs has spawned a grass root movement of those so affected to lobby for Black Box Warnings and Dear Doctor Letters as well as the petitioning of the FDA for the removal of some fluoroquinolone drugs from clinical practice.[112][113][114][115][116][117][118][119]
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