Doryx 100mg DR Tablets

Manufacturer WARNER CHILCOTT PROF PROD DIV Active Ingredient Doxycycline Delayed-Release Tablets(doks i SYE kleen) Pronunciation DOKS-ee-SYE-kleen
It is used to treat pimples (acne).It is used to treat or prevent bacterial infections.It is used to prevent malaria.It is used to treat swelling of the tissue around the teeth (periodontitis). It is used with scaling and root planing.It may be given to you for other reasons. Talk with the doctor.
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Drug Class
Antibiotic, Anti-acne agent, Antimalarial
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Pharmacologic Class
Tetracycline antibiotic
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Pregnancy Category
Category D
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FDA Approved
Jan 1967
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DEA Schedule
Not Controlled

Overview

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What is this medicine?

Doxycycline is an antibiotic used to treat many different types of bacterial infections, such as urinary tract infections, acne, gonorrhea, chlamydia, and gum disease. It can also be used to prevent malaria. It works by stopping the growth of bacteria.
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How to Use This Medicine

Taking Your Medication Correctly

To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. Continue taking your medication as directed by your doctor or healthcare provider, even if you start to feel better.

Special Instructions for Taking Your Medication

Some medications need to be taken with food, while others should be taken on an empty stomach. Check with your pharmacist to determine the best way to take your medication. It's also important to avoid taking your medication at the same time as milk, dairy products, or other foods that contain calcium, as this may reduce the effectiveness of the medication. If you have any questions, consult with your doctor or pharmacist.

Additional Tips

Drink plenty of non-caffeinated liquids, unless your doctor advises you to limit your fluid intake. Avoid taking certain medications, such as bismuth (Pepto-Bismol), calcium, iron, magnesium, zinc, multivitamins with minerals, colestipol, cholestyramine, didanosine, or antacids, within 2 hours of taking your medication.

How to Take Your Medication

Take your medication with a full glass of water. To minimize the risk of throat irritation, do not lie down after taking your medication. Ask your pharmacist how long you should wait before lying down. Swallow your medication whole; do not chew or crush it. If your doctor instructs you to break the tablet, you can do so. You can also sprinkle the contents of the tablet on applesauce, but be careful not to crush the pellets. Do not chew, crush, or damage the contents of the tablet. If you mix the medication with applesauce, swallow it immediately and do not store it for later use. Avoid mixing the medication with hot applesauce.

Storing and Disposing of Your Medication

Store your medication at room temperature, protected from light and moisture. Do not store it in a bathroom. Check the expiration date on the packaging and do not take the medication if it is outdated or has not been stored properly.

What to Do If You Miss a Dose

If you miss a dose, take it as soon as you remember. If it's close to the time for your next dose, skip the missed dose and continue with your regular schedule. Do not take two doses at the same time or take extra doses.
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Lifestyle & Tips

  • Take Doryx 100mg DR Tablets with a full glass of water (at least 8 ounces) to prevent irritation of the esophagus.
  • Remain in an upright position (sitting or standing) for at least 30 minutes, preferably 1 hour, after taking the medication to prevent esophageal irritation.
  • Avoid taking antacids, iron supplements, calcium supplements, or products containing bismuth subsalicylate (e.g., Pepto-Bismol) within 2-3 hours before or after taking Doryx, as they can interfere with absorption.
  • Avoid dairy products (milk, cheese, yogurt) within 2-3 hours before or after taking Doryx, as they can also interfere with absorption. Doryx DR formulation is less affected by food/dairy than immediate release, but separation is still a good precaution.
  • Doxycycline can make your skin more sensitive to sunlight (photosensitivity). Use sunscreen, wear protective clothing, and avoid prolonged sun exposure or tanning beds while taking this medication and for several days after stopping it.
  • Complete the full course of medication as prescribed, even if your symptoms improve, to prevent the infection from returning and to reduce the development of antibiotic resistance.
  • If you are taking oral contraceptives, consider using an additional non-hormonal birth control method (like condoms) as doxycycline may reduce the effectiveness of birth control pills, though this interaction is controversial.

Dosing & Administration

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Adult Dosing

Standard Dose: 100 mg every 12 hours or 200 mg once daily for most infections
Dose Range: 50 - 200 mg

Condition-Specific Dosing:

Acute Infections: 100 mg every 12 hours on day 1, then 100 mg once daily or 50 mg every 12 hours.
Severe Infections: 100 mg every 12 hours.
Acne Vulgaris: 20 mg twice daily or 50 mg once daily (sub-antimicrobial dose).
Malaria Prophylaxis: 100 mg once daily, starting 1-2 days before travel, continuing for 4 weeks after return.
Syphilis (early): 100 mg twice daily for 14 days.
Lyme Disease: 100 mg twice daily for 10-21 days.
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Pediatric Dosing

Neonatal: Not established (contraindicated due to dental effects)
Infant: Not established (contraindicated due to dental effects)
Child: Contraindicated in children under 8 years of age due to risk of permanent tooth discoloration and enamel hypoplasia. For children 8 years and older weighing less than 45 kg: 2.2 mg/kg body weight divided into two doses on the first day, then 2.2 mg/kg body weight given as a single daily dose or divided into two doses. For children 8 years and older weighing 45 kg or more: Adult dose.
Adolescent: Adult dose (typically 100 mg every 12 hours or 200 mg once daily)
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Dose Adjustments

Renal Impairment:

Mild: No adjustment needed
Moderate: No adjustment needed
Severe: No adjustment needed (primarily excreted via non-renal routes)
Dialysis: Not significantly removed by hemodialysis; no supplemental dose needed.

Hepatic Impairment:

Mild: No specific adjustment recommended
Moderate: Use with caution; monitor for increased adverse effects
Severe: Use with caution; monitor for increased adverse effects. Doxycycline is primarily eliminated by non-renal routes, but severe hepatic dysfunction may lead to accumulation.

Pharmacology

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Mechanism of Action

Doxycycline is a tetracycline antibiotic that inhibits bacterial protein synthesis by binding reversibly to the 30S ribosomal subunit, thereby preventing the binding of aminoacyl transfer RNA to the messenger RNA-ribosome complex. This action is bacteriostatic.
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Pharmacokinetics

Absorption:

Bioavailability: 90-100%
Tmax: 2-4 hours (for delayed-release formulations)
FoodEffect: Food, including dairy products, has a minimal effect on the absorption of Doryx (doxycycline hyclate delayed-release tablets) compared to other tetracyclines, which are significantly affected. However, it is recommended to take Doryx with food to minimize gastrointestinal irritation.

Distribution:

Vd: 0.7 L/kg
ProteinBinding: 80-95%
CnssPenetration: Limited (increases with inflamed meninges)

Elimination:

HalfLife: 16-22 hours
Clearance: Not readily available (primarily non-renal excretion)
ExcretionRoute: Primarily excreted unchanged in feces (via bile) and urine
Unchanged: Approximately 40% (renal) and 60% (fecal)
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Pharmacodynamics

OnsetOfAction: Variable, depends on infection type; generally within hours to days for clinical effect
PeakEffect: Correlates with peak plasma concentrations (2-4 hours post-dose)
DurationOfAction: Due to long half-life, allows for once or twice daily dosing

Safety & Warnings

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Side Effects

Urgent Side Effects: Seek Medical Help Right Away

Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:

Signs of an allergic reaction: rash, hives, itching, red, swollen, blistered, or peeling skin (with or without fever), wheezing, tightness in the chest or throat, trouble breathing, swallowing, or talking, unusual hoarseness, or swelling of the mouth, face, lips, tongue, or throat
Signs of liver problems: dark urine, tiredness, decreased appetite, upset stomach or stomach pain, light-colored stools, vomiting, or yellow skin or eyes
Signs of pancreatitis (pancreas problem): severe stomach pain, severe back pain, or severe upset stomach or vomiting
Chest pain or pressure, or a rapid heartbeat
Difficulty urinating or changes in urine output
Fever, chills, or sore throat; unexplained bruising or bleeding; or feeling extremely tired or weak
Throat irritation or trouble swallowing
Muscle or joint pain
Rapid breathing or flushing
Severe dizziness or fainting
Changes in skin color
Vaginal itching or discharge
Diarrhea (common with antibiotics), especially if severe, bloody, or watery (may be a sign of C. diff-associated diarrhea, a potentially life-threatening condition)

If you experience any of these symptoms, contact your doctor immediately.

Additional Important Warnings

C. diff-associated diarrhea (CDAD) may occur during or after antibiotic treatment, which can lead to a life-threatening bowel condition. If you experience stomach pain, cramps, or severe diarrhea, contact your doctor right away.
Raised pressure in the brain has been reported with this medication, which may cause headaches or vision problems (such as blurred vision, double vision, or loss of vision). If you experience any of these symptoms, contact your doctor immediately.

Other Possible Side Effects

While many people may not experience side effects or only have mild ones, it's essential to be aware of the following:

Diarrhea, upset stomach, or vomiting
Decreased appetite

If you're concerned about any side effects or if they persist or worsen, contact your doctor for guidance.

Reporting Side Effects

If you have questions or concerns about side effects, you can:

Contact your doctor for medical advice
Report side effects to the FDA at 1-800-332-1088
Submit a report online at https://www.fda.gov/medwatch
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Seek Immediate Medical Attention If You Experience:

  • Severe skin rash or blistering (signs of severe skin reaction)
  • Yellowing of the skin or eyes (jaundice), dark urine, severe stomach pain (signs of liver problems)
  • Severe headache, blurred vision, double vision, or vision loss (signs of pseudotumor cerebri)
  • Difficulty swallowing, painful swallowing, or chest pain (signs of esophageal irritation)
  • Severe diarrhea that is watery or bloody (signs of C. difficile infection)
  • Signs of a new infection (e.g., fever, sore throat, rash) that may indicate a superinfection (e.g., yeast infection)
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Before Using This Medicine

Before Taking This Medication: Important Information to Share with Your Doctor

It is essential to inform your doctor about the following:

Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the symptoms you experienced.
If you are currently taking any of the following medications: Acitretin, isotretinoin, or a penicillin.
* If you are breastfeeding or plan to breastfeed, as you may need to avoid breastfeeding while taking this medication.

Please note that this is not an exhaustive list of all potential interactions. To ensure your safety, it is crucial to discuss all of your medications (including prescription, over-the-counter, natural products, and vitamins) and health conditions with your doctor and pharmacist. Before starting, stopping, or changing the dose of any medication, consult with your doctor to confirm that it is safe to do so in conjunction with this medication.
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Precautions & Cautions

It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you are on long-term treatment with this drug, your doctor may recommend regular blood tests to monitor your condition.

This medication may interfere with certain laboratory tests, so be sure to notify all your healthcare providers and lab personnel that you are taking this drug. Do not exceed the prescribed duration of treatment, as this may increase the risk of a second infection.

You may be more susceptible to sunburn while taking this medication, so take necessary precautions when exposed to the sun. If you experience unusual sunburn or sensitivity, inform your doctor promptly.

There is a risk of severe skin reactions associated with this medication, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other serious conditions that can affect multiple organs. These reactions can be life-threatening. Seek immediate medical attention if you experience symptoms such as red, swollen, blistered, or peeling skin; red or irritated eyes; sores in your mouth, throat, nose, eyes, genitals, or skin; fever; chills; body aches; shortness of breath; or swollen glands.

If you are using birth control pills or other hormone-based contraception, note that this medication may reduce their effectiveness. Consider using an additional form of birth control, such as condoms, to prevent pregnancy.

In children under 8 years old, this medication may cause permanent tooth discoloration (yellow-gray brown) or affect bone growth. If taken during pregnancy, it may also cause tooth discoloration in the unborn baby. These changes are irreversible. Other tooth problems have been reported in children taking this medication. Discuss any concerns with your doctor.

Although this medication is not typically recommended for children under 8 years old, there may be exceptions. Consult with your doctor to determine the best course of treatment.

In some cases, adults have also experienced tooth discoloration, which has been reported to reverse after stopping the medication and undergoing dental cleaning. If you have concerns, discuss them with your doctor.

If you are pregnant or become pregnant while taking this medication, you should contact your doctor immediately, as it may harm the unborn baby.
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Overdose Information

Overdose Symptoms:

  • Nausea
  • Vomiting
  • Diarrhea
  • Liver damage (rare, but possible with very high doses)

What to Do:

Seek immediate medical attention or call a Poison Control Center (1-800-222-1222). Treatment is supportive and symptomatic. Gastric lavage may be considered if ingestion is recent. Doxycycline is not significantly removed by hemodialysis.

Drug Interactions

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Major Interactions

  • Antacids (containing aluminum, calcium, magnesium): Decreased doxycycline absorption.
  • Iron preparations (including multivitamins with iron): Decreased doxycycline absorption.
  • Bismuth subsalicylate: Decreased doxycycline absorption.
  • Oral retinoids (e.g., isotretinoin): Increased risk of pseudotumor cerebri (benign intracranial hypertension).
  • Penicillins: Tetracyclines may interfere with the bactericidal action of penicillin. Avoid concomitant use.
  • Warfarin and other anticoagulants: Doxycycline may potentiate the anticoagulant effect, requiring dose adjustment of the anticoagulant.
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Moderate Interactions

  • Barbiturates (e.g., phenobarbital), Carbamazepine, Phenytoin: May decrease doxycycline half-life due to enzyme induction.
  • Oral contraceptives: May decrease efficacy of oral contraceptives (though evidence is controversial, advise backup method).
  • Methotrexate: Tetracyclines may increase methotrexate levels by inhibiting renal tubular secretion.
  • Ergot alkaloids: Theoretical increased risk of ergotism.
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Minor Interactions

  • Cholestyramine: May decrease doxycycline absorption (separate administration by several hours).

Monitoring

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Baseline Monitoring

Liver function tests (ALT, AST, bilirubin)

Rationale: To establish baseline and identify pre-existing hepatic impairment, especially given its hepatic elimination route.

Timing: Prior to initiation, particularly in patients with known or suspected hepatic dysfunction.

Renal function tests (BUN, creatinine)

Rationale: To establish baseline, though doxycycline is primarily excreted non-renally, it's good practice for antibiotic use.

Timing: Prior to initiation.

Complete Blood Count (CBC)

Rationale: To establish baseline and monitor for potential hematologic abnormalities, though rare.

Timing: Prior to initiation.

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Routine Monitoring

Clinical response to therapy

Frequency: Daily/as clinically indicated

Target: Resolution of infection symptoms

Action Threshold: Lack of improvement or worsening symptoms may indicate treatment failure or resistance.

Signs/symptoms of adverse effects (e.g., GI upset, photosensitivity, candidiasis)

Frequency: Daily/as clinically indicated

Target: Absence of severe adverse effects

Action Threshold: Severe GI distress, severe sunburn, new fungal infections, or signs of esophageal irritation warrant evaluation and potential discontinuation.

INR (if on warfarin)

Frequency: Regularly, as per anticoagulant monitoring guidelines, with increased frequency upon initiation or dose change of doxycycline.

Target: Therapeutic range for indication

Action Threshold: INR outside target range requires anticoagulant dose adjustment.

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Symptom Monitoring

  • Nausea
  • Vomiting
  • Diarrhea
  • Abdominal pain
  • Heartburn
  • Difficulty swallowing
  • Chest pain (especially after taking dose)
  • Severe sunburn or rash after sun exposure
  • Vaginal itching or discharge (signs of candidiasis)
  • Oral thrush (white patches in mouth)
  • Headache (especially severe or persistent, could indicate pseudotumor cerebri)
  • Blurred vision or visual disturbances

Special Patient Groups

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Pregnancy

Doxycycline is classified as Pregnancy Category D. It should be avoided during pregnancy, especially during the second and third trimesters, due to the risk of permanent discoloration of deciduous teeth (yellow-gray-brown) and inhibition of bone growth in the fetus. Use only if the potential benefit justifies the potential risk to the fetus.

Trimester-Specific Risks:

First Trimester: Limited data, but theoretical risk of teratogenicity. Generally avoided.
Second Trimester: High risk of permanent tooth discoloration (deciduous teeth) and inhibition of bone growth.
Third Trimester: High risk of permanent tooth discoloration (deciduous teeth) and inhibition of bone growth.
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Lactation

Doxycycline is excreted into breast milk. While the amount transferred is generally low and calcium in milk may chelate the drug, there is a theoretical risk of dental staining and inhibition of bone growth in the nursing infant, especially with long-term use. The American Academy of Pediatrics considers tetracyclines compatible with breastfeeding with caution for short-term use. Monitor infant for diarrhea, candidiasis, and potential dental effects. Consider alternative agents or temporary interruption of breastfeeding for prolonged therapy.

Infant Risk: L3 (Moderate risk) - Theoretical risk of dental staining and bone growth inhibition; monitor infant for adverse effects.
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Pediatric Use

Contraindicated in children under 8 years of age due to the risk of permanent tooth discoloration (yellow-gray-brown) and enamel hypoplasia. Also, inhibition of bone growth has been observed in premature infants. For children 8 years and older, dosing is weight-based, and the risks of dental effects should still be considered, especially with repeated or prolonged courses.

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Geriatric Use

No specific dose adjustment is generally required for elderly patients based on age alone. However, elderly patients may be more susceptible to adverse effects such as gastrointestinal irritation or photosensitivity. Monitor renal and hepatic function if concerns exist, although doxycycline's non-renal excretion makes it a favorable option in renal impairment.

Clinical Information

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Clinical Pearls

  • Doryx is a delayed-release formulation designed to reduce gastrointestinal irritation, particularly esophageal irritation, compared to immediate-release doxycycline. However, taking it with a full glass of water and remaining upright is still crucial.
  • Despite the DR formulation, photosensitivity is a significant side effect; counsel patients on strict sun protection.
  • Doxycycline is a broad-spectrum antibiotic effective against a wide range of bacteria, including atypical organisms (e.g., Mycoplasma, Chlamydia), spirochetes (e.g., Borrelia burgdorferi), and some protozoa (e.g., Plasmodium falciparum for malaria prophylaxis).
  • It is a preferred agent for certain conditions like Lyme disease, Rocky Mountain Spotted Fever, and chlamydial infections.
  • The sub-antimicrobial dose (e.g., 20 mg BID or 50 mg QD) used for acne (e.g., Oracea) works primarily through anti-inflammatory mechanisms rather than direct antibacterial action, reducing the risk of resistance.
  • Unlike other tetracyclines, doxycycline does not accumulate significantly in patients with renal impairment, making it a safe choice for those with kidney disease.
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Alternative Therapies

  • Other tetracyclines (e.g., minocycline, tetracycline)
  • Macrolides (e.g., azithromycin, erythromycin) for atypical infections or penicillin allergies
  • Fluoroquinolones (e.g., ciprofloxacin, levofloxacin) for certain bacterial infections
  • Beta-lactam antibiotics (e.g., amoxicillin, penicillin) for susceptible bacterial infections
  • Topical or other oral agents for acne (e.g., retinoids, benzoyl peroxide, other antibiotics)
  • Other antimalarials (e.g., mefloquine, atovaquone/proguanil)
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Cost & Coverage

Average Cost: $100 - $500+ per 30 tablets (Doryx brand)
Generic Available: Yes
Insurance Coverage: Tier 2 or 3 (Brand), Tier 1 (Generic)
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General Drug Facts

If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe and effective treatment, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it is a good idea to consult with your pharmacist. If you have any questions or concerns about this medication, do not hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide detailed information about the overdose, including the medication taken, the amount, and the time it occurred.