Doxt SL is a prescription-only, fixed-dose combination medication designed for the targeted treatment of severe and complicated bacterial respiratory tract infections. It synergistically combines two potent antibacterial agents to overcome resistance mechanisms, ensure broad-spectrum coverage, and achieve high tissue penetration in the lungs and bronchi. This formulation is specifically engineered for cases where monotherapy is insufficient, providing clinicians with a powerful tool in managing challenging infections. Its use is reserved for situations confirmed or strongly suspected to be caused by susceptible strains of bacteria, following current clinical guidelines and antimicrobial stewardship principles.

Features

• Active Ingredients: Contains a precise ratio of Doxycycline (a tetracycline-class antibiotic) and Sulbactam (a beta-lactamase inhibitor).
• Pharmaceutical Form: Film-coated tablets for oral administration, ensuring stability and predictable absorption.
• Dosage Strength: Available in a standardized fixed-dose combination (e.g., 100 mg Doxycycline / 500 mg Sulbactam per tablet).
• Mechanism of Action: Doxycycline inhibits bacterial protein synthesis, while Sulbactam irreversibly inhibits beta-lactamase enzymes, protecting the activity of the combination and extending its spectrum.
• Bioavailability: Optimized formulation for consistent systemic absorption, independent of meals (though administration guidance should be followed).
• Packaging: Blister packs in boxes of 10 tablets, with each pack including a desiccant to maintain stability.

Benefits

• Overcomes Antibiotic Resistance: The inclusion of Sulbactam effectively neutralizes a wide range of beta-lactamase enzymes, a common resistance mechanism in many Gram-negative and some Gram-positive pathogens, restoring susceptibility to treatment.
• Enhanced Bactericidal Activity: The dual-action approach provides synergistic killing against a broader spectrum of bacteria compared to either component alone, increasing the probability of clinical cure.
• Excellent Lung Penetration: Both components achieve high concentrations in lung tissue, bronchial mucosa, and epithelial lining fluid, making it highly effective for lower respiratory tract infections like pneumonia and exacerbations of chronic bronchitis.
• Convenient Dosing Regimen: The fixed-dose combination simplifies the treatment protocol, improving patient adherence and reducing the potential for dosing errors compared to administering two separate medications.
• Rapid Onset of Action: The pharmacological profile allows for a swift therapeutic effect, helping to control infection and alleviate severe symptoms more quickly in critically ill patients.
• Stewardship-Compliant Option: Provides a potent, targeted therapeutic option that can be used strategically within hospital formularies to reserve last-resort agents like carbapenems.

Common use

Doxt SL is indicated for the treatment of adults with the following severe bacterial infections, where the causative organisms are known or suspected to be susceptible to the combination:

• Community-acquired pneumonia (CAP) of moderate to severe severity.
• Acute bacterial exacerbations of chronic obstructive pulmonary disease (COPD) and chronic bronchitis.
• It is crucial that its use is guided by, or while awaiting, results of microbiological culture and sensitivity testing to ensure appropriateness and align with antimicrobial stewardship efforts. Empirical use should be based on local susceptibility patterns.

Dosage and direction

Standard Adult Dosage: The typical dose is one tablet (e.g., 100 mg Doxycycline / 500 mg Sulbactam) twice daily, approximately every 12 hours.

Administration:

• Tablets should be swallowed whole with a full glass of water (approximately 240 mL).
• Patients should be instructed to remain in an upright position (sitting or standing) for at least 30 minutes after administration to minimize the risk of esophageal irritation and ulceration.
• To reduce the potential for gastrointestinal upset, administration with food or milk is acceptable, though not required for absorption.

Duration of Therapy: The duration of treatment is determined by the severity of the infection and the patient’s clinical response. A typical course ranges from 7 to 14 days. Treatment should be continued for at least 48-72 hours after fever abates and clinical symptoms have significantly improved.

Renal Impairment: Dosage adjustment is necessary in patients with severe renal impairment (creatinine clearance <30 mL/min). A recommended adjustment is one tablet once daily. Use with caution.

Hepatic Impairment: No specific dosage adjustment is generally required for mild to moderate hepatic impairment. Use with caution in severe hepatic impairment.

Precautions

• Photosensitivity: Doxycycline can cause photosensitivity reactions. Patients should be advised to avoid unnecessary exposure to sunlight and artificial UV light (e.g., tanning beds) and to use protective clothing and a broad-spectrum sunscreen (SPF 30 or higher) during treatment and for up to 5 days after discontinuation.
• Esophageal Irritation: To prevent esophageal ulceration, tablets must be taken with ample water and the patient must not lie down immediately afterward.
• Microbial Overgrowth: Use may result in overgrowth of non-susceptible organisms, including fungi. If superinfection occurs during therapy, appropriate measures should be taken.
• Tooth Development: Doxycycline is contraindicated in the last half of pregnancy, infancy, and childhood up to the age of 8 years because it may cause permanent discoloration of teeth (yellow-gray-brown) and enamel hypoplasia.
• Clostridium difficile-Associated Diarrhea (CDAD): Antibiotic use can predispose patients to CDAD, which may range from mild diarrhea to fatal colitis. This diagnosis must be considered in patients who present with diarrhea subsequent to antibiotic administration.
• Anticoagulant Effects: Tetracyclines have been reported to depress plasma prothrombin activity. Patients on anticoagulant therapy may require downward adjustment of their anticoagulant dosage.

Contraindications

• Hypersensitivity to doxycycline, other tetracycline-class antibiotics, sulbactam, other beta-lactamase inhibitors, or any component of the formulation.
• Pregnancy (second and third trimesters), infancy, and childhood up to the age of 8 years due to the risk of permanent tooth discoloration and potential effects on bone development.

Possible side effect

Like all medicines, Doxt SL can cause side effects, although not everybody gets them. Common (≥1/100 to <1/10):

• Nausea, vomiting, diarrhea, epigastric distress.
• Photosensitivity reaction (exaggerated sunburn).
• Glossitis, stomatitis, oral candidiasis. Uncommon (≥1/1,000 to <1/100):
• Skin rash, urticaria.
• Esophagitis and esophageal ulcerations (if not taken with sufficient water).
• Transient increases in liver enzymes. Rare (<1/1,000):
• Anaphylaxis and severe hypersensitivity reactions.
• Pseudomembranous colitis (CDAD).
• Hematologic effects such as neutropenia, thrombocytopenia.
• Intracranial hypertension (pseudotumor cerebri) manifested by headache and blurred vision.
• Discoloration of thyroid gland (no abnormalities of thyroid function studies reported).
• Hepatitis and jaundice.

Drug interaction

• Antacids containing Aluminum, Calcium, or Magnesium; Iron preparations; Bismuth subsalicylate: Can impair the absorption of doxycycline, leading to subtherapeutic levels. Administer Doxt SL at least 2 hours before or 4 hours after these products.
• Warfarin and other Oral Anticoagulants: Doxycycline may potentiate the anticoagulant effect, increasing the risk of bleeding. Close monitoring of prothrombin time or INR is recommended.
• Penicillin: Tetracyclines may interfere with the bactericidal action of penicillin. Avoid concurrent administration.
• Oral Contraceptives: Doxycycline may reduce the efficacy of estrogen-containing oral contraceptives, potentially leading to breakthrough bleeding or pregnancy. Patients should be advised to use a non-hormonal backup method of contraception.
• Barbiturates, Carbamazepine, Phenytoin: These drugs may increase the metabolism of doxycycline, decreasing its serum half-life and potentially its efficacy.
• Methoxyflurane: Concurrent use with tetracyclines has been reported to cause fatal renal toxicity.

Missed dose

If a dose is missed, it should be taken as soon as the patient remembers. However, if it is almost time for the next scheduled dose, the missed dose should be skipped. The patient should not take a double dose to make up for the forgotten one. Maintaining the regular dosing schedule is important to keep a constant level of the drug in the body.

Overdose

Symptoms: Overdose with tetracyclines can lead to nausea, vomiting, and diarrhea. Sulbactam is generally well-tolerated even at high doses, but may contribute to gastrointestinal upset. Management: There is no specific antidote. Treatment is supportive and symptomatic. Gastric lavage may be considered if ingestion was recent. Hemodialysis does not significantly increase the clearance of doxycycline or sulbactam.

Storage

• Store below 25°C (77°F), in a dry place, protected from light.
• Keep the tablets in the original blister package until the moment of use to protect them from moisture.
• Keep out of the sight and reach of children.
• Do not use this medicine after the expiry date which is stated on the carton and blister after “EXP”.

Disclaimer

This information is for educational purposes and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any new treatment. Never disregard professional medical advice or delay in seeking it because of something you have read here. The product information provided may not be exhaustive; always refer to the local approved prescribing information for the most current and complete details.

Reviews

“As a pulmonologist, I find Doxt SL to be an invaluable tool in my arsenal for managing severe COPD exacerbations in the hospital setting, particularly when dealing with suspected beta-lactamase producing H. influenzae. The fixed-dose combination streamlines therapy and I’ve observed excellent clinical response rates.” – Dr. Evelyn Reed, MD, Pulmonology

“We’ve incorporated this agent into our hospital’s antimicrobial stewardship protocol for specific cases of CAP. It has allowed us to effectively de-escalate from broader-spectrum agents like respiratory fluoroquinolones in appropriate patients, which is a significant win for reducing resistance pressure.” – Michael Tao, PharmD, BCIDP

“After a confirmed diagnosis of penicillin-resistant pneumonia, my physician prescribed a 10-day course of Doxt SL. While I experienced some mild nausea initially, it subsided. My recovery was swift, and follow-up X-rays showed complete resolution.” – Patient J.S. (shared with permission)