A fixed-dose combination of a broad-spectrum tetracycline antibiotic (Doxycycline) and a probiotic (Lactobacillus). Doxycycline inhibits bacterial protein synthesis, while Lactobacillus spores help restore gut flora, potentially mitigating antibiotic-associated diarrhea and maintaining intestinal homeostasis. This combination is particularly relevant in the Indian context for managing infections in outpatient settings where compliance and GI tolerability are concerns.
Adult: 100 mg Doxycycline twice daily on the first day (loading dose), followed by 100 mg once daily. For severe infections, 100 mg twice daily may be continued. The Lactobacillus dose (60M spores) is concurrent with each antibiotic dose.
Note: Take Doxycycline + Lactobacillus with a full glass of water while sitting or standing, at least 1 hour before or 2 hours after meals. Do NOT take with dairy products, antacids, calcium, iron, or magnesium supplements. The probiotic can be taken with the antibiotic dose as the spores are resistant.
Doxycycline binds reversibly to the 30S ribosomal subunit of susceptible bacteria, inhibiting the binding of aminoacyl-tRNA to the mRNA-ribosome complex, thereby inhibiting protein synthesis. It is bacteriostatic. Lactobacillus spores germinate in the intestine into viable bacteria that compete with pathogens for adhesion sites and nutrients, produce bacteriocins, lower luminal pH, and modulate the host immune response.
Pregnancy: Category D. Doxycycline is contraindicated in pregnancy, especially second and third trimesters. It can cause retardation of fetal skeletal development, dental discoloration, and maternal hepatotoxicity. Lactobacillus is generally considered safe.
Driving: Generally safe. However, be cautious if dizziness, vertigo, or visual disturbances (signs of intracranial hypertension) occur.
| Antacids (Al, Ca, Mg), Iron, Zinc, Bismuth subsalicylate | Markedly reduced absorption of doxycycline due to chelation. | Major |
| Warfarin | Doxycycline may potentiate anticoagulant effect; increased INR risk. | Major |
| Oral Contraceptives (Estrogen-containing) | Antibiotic may reduce efficacy, leading to contraceptive failure. Use backup method. | Moderate |
| Penicillins (e.g., Amoxicillin) | Antagonistic antibacterial effect; avoid concurrent use. | Moderate |
| Anticonvulsants (Carbamazepine, Phenytoin, Barbiturates) | Increased metabolism of doxycycline, reducing its half-life and efficacy. | Moderate |
| Methoxyflurane | Concurrent use with tetracyclines can cause fatal nephrotoxicity. | Major |
| Isotretinoin | Increased risk of intracranial hypertension. Avoid concomitant use. | Major |
| Digoxin | Doxycycline may increase digoxin bioavailability by altering gut flora. | Moderate |
Same composition (Doxycycline (100mg) + Lactobacillus (60Million spores)), different brands: