Doryx 100mg DR Tablets
Overview
What is this medicine?
How to Use This Medicine
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 Check the expiration date on the packaging and do not take the medication if it is outdated or has not been stored properly.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.
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.
Available Forms & Alternatives
Available Strengths:
Generic Alternatives:
Dosing & Administration
Adult Dosing
Condition-Specific Dosing:
Pediatric Dosing
Dose Adjustments
Renal Impairment:
Hepatic Impairment:
Pharmacology
Mechanism of Action
Pharmacokinetics
Absorption:
Distribution:
Elimination:
Pharmacodynamics
Safety & Warnings
Side Effects
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
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)
Before Using This Medicine
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.
Precautions & Cautions
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.
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
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.
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.
Minor Interactions
- Cholestyramine: May decrease doxycycline absorption (separate administration by several hours).
Monitoring
Baseline Monitoring
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.
Rationale: To establish baseline, though doxycycline is primarily excreted non-renally, it's good practice for antibiotic use.
Timing: Prior to initiation.
Rationale: To establish baseline and monitor for potential hematologic abnormalities, though rare.
Timing: Prior to initiation.
Routine Monitoring
Frequency: Daily/as clinically indicated
Target: Resolution of infection symptoms
Action Threshold: Lack of improvement or worsening symptoms may indicate treatment failure or resistance.
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.
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.
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
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:
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.
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.
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
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.
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)