Doryx Information
Doryx ()
Doryx () Description
Doryx () Capsules contain specially coated pellets of doxycycline hyclate, a broad-spectrum antibiotic synthetically derived from oxytetracycline, in a delayed-release formulation for oral administration.
The structural formula for doxycycline hyclate is
with a molecular formula of CHNO, HCl, ½ CHO, ½ HO and a molecular weight of 512.9. The chemical designation for doxycycline hyclate is [4S (4aR, 5S, 5aR, 6R, 12aS)]-4-(dimethylamino)-1,4,4a, 5,5a, 6, 11,12a-octahydro-3, 5,10,12,12a-pentahydroxy-6-methyl-1, 11-deoxonapthtacene-2-carboxamide monohydrochloride, compound with ethyl alcohol (2:1), monohydrate.
Doxycycline hyclate is a yellow crystalline powder soluble in water and in solutions of alkali hydroxides and carbonates. Doxycycline has a high degree of lipid solubility and a low affinity for calcium binding. It is highly stable in normal human serum. Doxycycline will not degrade into an epianhydro form.
Inert ingredients in the capsule formulation are: lactose; microcrystalline cellulose; povidone; starch wheat; magnesium stearate; cellulosic polymer coating. The capsule shell and/or band contains FD and C blue No. 1; FD and C yellow No. 6; D and C yellow No. 10; gelatin; silicon dioxide; sodium lauryl sulfate; titanium dioxide.
Doryx () Clinical Pharmacology
Tetracyclines are readily absorbed and are bound to plasma proteins in varying degree. They are concentrated by the liver in the bile, and excreted in the urine and feces at high concentrations and in a biologically active form. Doxycycline is virtually completely absorbed after oral administration.
Following a 200 mg dose, normal adult volunteers averaged peak serum levels of 2.6 mcg/mL of doxycycline at 2 hours decreasing to 1.45 mcg/mL at 24 hours. Excretion of doxycycline by the kidney is about 40%/72 hours in individuals with normal function (creatinine clearance about 75 mL/min). This percentage excretion may fall as low as 1-5%/72 hours in individuals with severe renal insufficiency (creatinine clearance below 10 mL/min). Studies have shown no significant difference in serum half-life of doxycycline (range 18-22 hours) in individuals with normal and severely impaired renal function.
Hemodialysis does not alter serum half-life.
Results of animal studies indicate that tetracyclines cross the placenta and are found in fetal tissues.
Doryx () Indications And Usage
To reduce the development of drug-resistant bacteria and maintain the effectiveness of Doryx () and other antibacterial drugs, Doryx () should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.
Doxycycline is indicated for the treatment of the following infections:
Doxycycline is also indicated for the treatment of infections caused by the following gram-negative microorganisms:
Because many strains of the following groups of microorganisms have been shown to be resistant to doxycycline, culture and susceptibility testing are recommended.
Doxycycline is indicated for treatment of infections caused by the following gram-negative microorganisms, when bacteriological testing indicates appropriate susceptibility to the drug:
Doxycycline is indicated for treatment of infections caused by the following gram-positive microorganisms when bacteriological testing indicates appropriate susceptibility to the drug:
Anthrax due to , including inhalation anthrax (post-exposure): to reduce the incidence or progression of disease following exposure to aerosolized .
When penicillin is contraindicated, doxycycline is an alternative drug in the treatment of infections due to:
In acute intestinal amebiasis doxycycline may be a useful adjunct to amebicides.
In severe acne doxycycline may be useful adjunctive therapy.
Doryx () Contraindications
The drug is contraindicated in persons who have shown hypersensitivity to any of the tetracyclines.
Doryx () Warnings
THE USE OF DRUGS OF THE TETRACYCLINE CLASS DURING TOOTH DEVELOPMENT (LAST HALF OF PREGNANCY, INFANCY AND CHILDHOOD TO THE AGE OF 8 YEARS) MAY CAUSE PERMANENT DISCOLORATION OF THE TEETH (YELLOW-GRAY-BROWN). This adverse reaction is more common during long-term use of the drugs but it has been observed following repeated short-term courses. Enamel hypoplasia has also been reported. TETRACYCLINE DRUGS, THEREFORE, SHOULD NOT BE USED IN THIS AGE GROUP, EXCEPT FOR ANTHRAX, INCLUDING INHALATION ANTHRAX (POST-EXPOSURE), UNLESS OTHER DRUGS ARE NOT LIKELY TO BE EFFECTIVE OR ARE CONTRAINDICATED.
If CDAD is suspected or confirmed, ongoing antibiotic use not directed against may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of , and surgical evaluation should be instituted as clinically indicated.
All tetracyclines form a stable calcium complex in any bone-forming tissue. A decrease in fibula growth rate has been observed in prematures given oral tetracycline in doses of 25 mg/kg every six hours. This reaction was shown to be reversible when the drug was discontinued.
Results of animal studies indicate that tetracyclines cross the placenta, are found in fetal tissues and can have toxic effects on the developing fetus (often related to retardation of skeleton development). Evidence of embryotoxicity has been noted in animals treated early in pregnancy. If any tetracycline is used during pregnancy or if the patient becomes pregnant while taking these drugs, the patient should be apprised of potential hazard to the fetus.
The anti-anabolic action of the tetracyclines may cause an increase in BUN. Studies to date indicate that this does not occur with the use of doxycycline in patients with impaired renal function.
Photosensitivity manifested by an exaggerated sunburn reaction has been observed in some individuals taking tetracyclines. Patients apt to be exposed to direct sunlight or ultraviolet light should be advised that this reaction can occur with tetracycline drugs, and treatment should be discontinued at the first evidence of skin erythema.
Doryx () Precautions
As with other antibiotic preparations, use of this drug may result in overgrowth of non-susceptible organisms, including fungi. If superinfection occurs, the antibiotic should be discontinued and appropriate therapy instituted.
Bulging fontanels in infants and benign intracranial hypertension in adults have been reported in individuals receiving tetracyclines. These conditions disappeared when the drug was discontinued.
Incision and drainage or other surgical procedures should be performed in conjunction with antibiotic therapy, when indicated.
Doxycycline offers substantial but not complete suppression of the asexual blood stages of strains.
Doxycycline does not suppress sexual blood stage gametocytes. Subjects completing this prophylactic regimen may still transmit the infection to mosquitoes outside endemic areas.
Prescribing Doryx () in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.
Patients taking doxycycline for malaria prophylaxis should be advised:
All patients taking doxycycline should be advised:
Diarrhea is a common problem caused by antibiotics which usually ends when the antibiotic is discontinued. Sometimes after starting treatment with antibiotics, patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as two or more months after having taken the last dose of the antibiotic. If this occurs, patients should contact their physician as soon as possible.
Patients should be counseled that antibacterial drugs including Doryx () should only be used to treat bacterial infections. They do not treat viral infections (e.g., the common cold). When Doryx () is prescribed to treat a bacterial infection, patients should be told that although it is common to feel better early in the course of therapy, the medication should be taken exactly as directed. Skipping doses or not completing the full course of therapy may (1) decrease the effectiveness of the immediate treatment and (2) increase the likelihood that bacteria will develop resistance and will not be treatable by Doryx () or other antibacterial drugs in the future,
In venereal disease when coexistent syphilis is suspected, dark-field examination should be done before treatment is started and the blood serology repeated monthly for at least 4 months.
In long-term therapy, periodic laboratory evaluation of organ systems, including hematopoietic, renal, and hepatic studies should be performed.
Because tetracyclines have been shown to depress plasma prothrombin activity, patients who are on anticoagulant therapy may require downward adjustment of their anticoagulant dosage.
Since bacteriostatic drugs may interfere with the bactericidal action of penicillin, it is advisable to avoid giving tetracyclines in conjunction with penicillin.
Absorption of tetracyclines is impaired by antacids containing aluminum, calcium, or magnesium, and iron-containing preparations.
Absorption of tetracyclines is impaired by bismuth subsalicylate.
Barbiturates, carbamazepine, and phenytoin decrease the half-life of doxycycline.
The concurrent use of tetracycline and Penthrane (methoxyflurane) has been reported to result in fatal renal toxicity.
Concurrent use of tetracycline may render oral contraceptives less effective.
Long-term studies in animals to evaluate carcinogenic potential of doxycycline have not been conducted. However, there has been evidence of oncogenic activity in rats in studies with the related antibiotics, oxytetracycline (adrenal and pituitary tumors) and minocycline (thyroid tumors).
Likewise, although mutagenicity studies of doxycycline have not been conducted, positive results in mammalian cell assays have been reported for related antibiotics (tetracycline, oxytetracycline).
Doxycycline administered orally at dosage levels as high as 250 mg/kg/day had no apparent effect on the fertility of female rats. Effect on male fertility has not been studied.
Doryx () Adverse Reactions
Due to oral doxycycline’s virtually complete absorption, side effects to the lower bowel, particularly diarrhoea, have been infrequent. The following adverse reactions have been observed in patients receiving tetracyclines:
Gastrointestinal: Anorexia, nausea, vomiting, diarrhoea, glossitis, dysphagia, enterocolitis, and inflammatory lesions (with monilial overgrowth) in the anogenital region. Hepatotoxicity has been reported rarely. These reactions have been caused by both the oral and parenteral administration of tetracyclines. Rare instances of esophagitis and esophageal ulcerations have been reported in patients receiving capsule and tablet forms of drugs in the tetracycline class. Most of these patients took medications immediately before going to bed. (see ).
Skin: Maculopapular and erythematous rashes. Exfoliative dermatitis has been reported but is uncommon. Photosensitivity is discussed above (see ).
Renal toxicity: Rise in BUN has been reported and is apparently dose related. (see ).
Hypersensitivity reactions: Urticaria, angioneurotic edema, anaphylaxis, anaphylactoid purpura, serum sickness, pericarditis, and exacerbation of systemic lupus erythematosus.
Blood: Hemolytic anemia, thrombocytopenia, neutropenia and eosinophilia have been reported.
Other: Bulging fontanels in infants and benign intracranial hypertension in adults (See -).
When given over prolonged periods, tetracyclines have been reported to produce brown-black microscopic discolouration of thyroid glands. No abnormalities of thyroid functions are known to occur.
Doryx () Overdosage
In case of overdosage, discontinue medication, treat symptomatically and institute supportive measures. Dialysis does not alter serum half-life and thus would not be of benefit in treating cases of overdosage.
Doryx () Dosage And Administration
THE USUAL DOSAGE AND FREQUENCY OF ADMINISTRATION OF DOXYCYCLINE DIFFERS FROM THAT OF THE OTHER TETRACYCLINES. EXCEEDING THE RECOMMENDED DOSAGE MAY RESULT IN AN INCREASED INCIDENCE OF SIDE EFFECTS.
Adults: The usual dose of oral doxycycline is 200 mg on the first day of treatment (administered 100 mg every 12 hours) followed by a maintenance dose of 100 mg/day. The maintenance dose may be administered as a single dose or 50 mg every 12 hours. In the management of more severe infections (particularly chronic infections of the urinary tract), 100 mg every 12 hours is recommended.
For children above eight years of age: The recommended dosage schedule for children weighing 100 pounds or less is 2 mg/lb of body weight divided into two doses on the first day of treatment, followed by 1 mg/lb of body weight given as a single daily dose or divided into two doses on subsequent days. For more severe infections up to 2 mg/lb of body weight may be used. For children over 100 pounds, the usual adult dose should be used.
The therapeutic antibacterial serum activity will usually persist for 24 hours following recommended dosage.
When used in streptococcal infections, therapy should be continued for 10 days.
Administration of adequate amounts of fluid along with capsule and tablet forms of drugs in the tetracycline class is recommended to wash down the drugs and reduce the risk of esophageal irritation and ulceration (see ).
If gastric irritation occurs, doxycycline may be given with food or milk. Studies to date have indicated that administration of doxycycline at the usual recommended doses does not lead to excessive accumulation of the antibiotic in patients with renal impairment.
Uncomplicated gonococcal infections in adults (except anorectal infections in men): 100 mg, by mouth, twiceaday for 7 days. As an alternate single visit dose, administer 300 mg stat followed in one hour by a second 300 mg dose. The dose may be administered with food, including milk or carbonated beverage, as required.
Uncomplicated urethral, endocervical, or rectal infection in adults caused by 100 mg by mouth, twice a day for 7 days.
Nongonococcal urethritis (NGU) caused by and 100 mg, by mouth, twice a day for 7 days.
Syphilis – early: Patients who are allergic to penicillin should be treated with doxycycline 100 mg by mouth twice a day for 2 weeks.
Syphilis of more than one year’s duration: Patients who are allergic to penicillin should be treated with doxycycline 100 mg by mouth twice a day for 4 weeks.
Acute epididymo-orchitis caused by 100 mg, by mouth, twiceaday for at least 10 days.
Acute epididymo-orchitis caused by 100 mg, by mouth, twice a day for at least 10 days.
For prophylaxis of malaria: For adults, the recommended dose is 100 mg daily. For children over 8 years of age, the recommended dose is 2 mg/kg given once daily up to the adult dose. Prophylaxis should begin 1-2 days before travel to the malarious area. Prophylaxis should be continued daily during travel in the malarious area and for 4 weeks after the traveller leaves the malarious area.
Inhalation anthrax (post-exposure):
ADULTS: 100 mg of doxycycline, by mouth twiceaday for 60 days.
CHILDREN: weighing less than 100 lb (45 kg); 1 mg/lb (2.2 mg/kg) of body weight, by mouth, twiceaday for 60 days. Children weighing 100 lb or more should receive the adult dose.
Doryx () Capsules may also be administered by carefully opening the capsules and sprinkling the capsule contents on a spoonful of applesauce. However, any loss of pellets in the transfer would prevent using the dose. The applesauce should be swallowed immediately without chewing and followed with a cool 8-ounce glass of water to ensure complete swallowing of the capsule contents. The applesauce should not be hot, and it should be soft enough to be swallowed without chewing. In the event that a prepared dose of applesauce / Doryx () pellets cannot be taken immediately, the mixture should be discarded and not stored for later use.
Doryx () How Supplied
Doryx () (doxycycline hyclate) Delayed-Release Capsules, 100 mg have a dark yellow transparent body with light blue opaque cap; the capsule bearing the inscription “Doryx () ” and “WC” in a circle, printed in white. Pellets are coloured yellow. Each capsule contains specially coated pellets of doxycycline hyclate equivalent to 100 mg of doxycycline, supplied in:
Bulk containers of 60,000 capsules (NDC 50546-400-01).
Doryx () (doxycycline hyclate) Delayed-Release Capsules, 75 mg have an orange transparent body with opaque green cap; the capsule bearing the inscription “Doryx () ” on the cap and “75mg” on the body, printed in black. Pellets are coloured yellow. Each capsule contains specially coated pellets of doxycycline hyclate equivalent to 75 mg doxycycline, supplied in:
Bulk containers of 60,000 capsules (NDC 50546-550-01).
Doryx () Storage Conditions
Doryx () Animal Pharmacology And Toxicology
Hyperpigmentation of the thyroid has been produced by members of the tetracycline class in the following species: in rats by oxytetracycline, doxycycline, tetracycline PO, and methacycline; in minipigs by doxycycline, minocycline, tetracycline PO, and methacycline; in dogs by doxycycline and minocycline; in monkeys by minocycline.
Minocycline, tetracycline PO, methacycline, doxycycline, tetracycline base, oxytetracycline HCl, and tetracycline HCl were goitrogenic in rats fed a low iodine diet. This goitrogenic effect was accompanied by high radioactive iodine uptake. Administration of minocycline also produced a large goiter with high radioiodine uptake in rats fed a relatively high iodine diet.
Treatment of various animal species with this class of drugs has also resulted in the induction of thyroid hyperplasia in the following: in rats and dogs (minocycline); in chickens (chlortetracycline); and in rats and mice (oxytetracycline). Adrenal gland hyperplasia has been observed in goats and rats treated with oxytetracycline.
Doryx ()
