Pronil500 mg

Pronil is a nitroimidazole antimicrobial with antiprotozoal and antibacterial activity. Its indications differ somewhat by regulatory approval, but Pronil is used for the following:

Established / Approved Uses

• Bacterial vaginosis in patients 12 years of age and older — treated with a single oral dose of Pronil.
• Trichomoniasis (infection with Trichomonas vaginalis) in patients 12 years and older — treated with a single oral dose of Pronil; sexual partners should be treated at the same time to prevent reinfection.
• Intestinal amoebiasis (acute and asymptomatic/cyst-passer forms caused by Entamoeba histolytica) — a long-standing, guideline-supported use of Pronil in many countries, including Bangladesh.
• Hepatic (extra-intestinal) amoebiasis — Pronil is used as part of the overall management, generally alongside supportive care and, where indicated, drainage of an amoebic liver abscess.
• Giardiasis (infection with Giardia lamblia/duodenalis) — an established indication for Pronil outside the United States.

Pronil is particularly valued because its long half-life allows effective single-dose regimens in several of these infections, which can improve patient adherence compared with multi-day nitroimidazole courses.

Each tablet contains Secnidazole INN 500 mg or 1000 mg. Secnidazole is also formulated internationally as oral granules (2 g single-dose sachet) intended to be sprinkled onto soft food. Strength and dosage form available depend on the specific brand.

Pronil is a synthetic second-generation 5-nitroimidazole derivative closely related to metronidazole and tinidazole, but with a substantially longer plasma half-life. This pharmacokinetic property allows Pronil to maintain therapeutically effective concentrations after a single oral dose, making it useful for single-dose treatment of certain protozoal and bacterial infections.

Pronil is rapidly and almost completely absorbed after oral administration, with peak plasma concentrations reached in about 3 to 4 hours and an elimination half-life of roughly 17–29 hours (commonly cited as approximately 20 hours), permitting sustained antimicrobial activity for up to 72 hours after a single dose.

Pronil belongs to the nitroimidazole class of antimicrobial agents (a second-generation nitroimidazole), structurally related to metronidazole and tinidazole. It is classified as an antiprotozoal and antibacterial agent, primarily active against anaerobic bacteria and certain protozoa.

Secnidazole enters susceptible anaerobic and microaerophilic organisms by passive diffusion. Inside the cell, the nitro group of Secnidazole is reduced by low-redox-potential electron transport proteins unique to anaerobic organisms and protozoa, generating cytotoxic intermediates and free radicals. These reactive species bind to and cause strand breakage and destabilization of the organism's DNA helix, inhibiting nucleic acid synthesis and leading to cell death.

This mechanism accounts for the activity of Secnidazole against protozoa such as Trichomonas vaginalis, Entamoeba histolytica, and Giardia lamblia, as well as against many anaerobic bacteria associated with bacterial vaginosis (e.g., Gardnerella vaginalis and other anaerobes), while aerobic organisms lacking this reductive pathway are generally unaffected.

Pharmacokinetics: Secnidazole is well absorbed orally (peak plasma levels around 3–4 hours), widely distributed into body tissues and fluids, partially metabolized in the liver, and eliminated with a half-life of approximately 17–29 hours, with a portion excreted unchanged in urine over several days.

Pronil is administered orally. Tablets may be taken with or after food to reduce the chance of nausea. The oral granule formulation of Pronil must be sprinkled onto soft food (not dissolved in liquid) and eaten within 30 minutes without chewing the granules. Do not split or crush tablets of Pronil unless directed by a physician or pharmacist.

Pronil has a limited number of well-established clinically significant interactions:

• Alcohol: Concomitant use with alcohol may produce a disulfiram-like reaction (flushing, nausea, vomiting, abdominal cramps, headache). Alcohol should be avoided during treatment with Pronil and for at least 3 days after the last dose.
• Disulfiram: Co-administration with disulfiram is not recommended, as nitroimidazoles such as Pronil may cause psychotic reactions when combined with disulfiram.
• Warfarin and other coumarin anticoagulants: Pronil may potentiate the anticoagulant effect, prolonging prothrombin time; more frequent monitoring of coagulation parameters is advised if these drugs are used together.
• Hormonal contraceptives: No clinically significant interaction has been demonstrated between Pronil and combined oral contraceptives.

Most adverse effects of Pronil are mild and self-limiting.

• Common: nausea, altered/metallic taste (dysgeusia), headache, abdominal pain, diarrhea or vomiting, and vulvovaginal candidiasis (yeast infection) when used for bacterial vaginosis or trichomoniasis.
• Less common: urticaria (hives) and other hypersensitivity skin reactions, reversible leukopenia, dizziness, and vulvovaginal pruritus.
• Rare (typically with prolonged or high-dose use): vertigo, ataxia, and peripheral neuropathy (numbness or tingling in extremities).

Patients should seek medical attention if severe skin reactions, persistent neurological symptoms, or signs of blood dyscrasia (unusual bruising, bleeding, infection) occur while taking Pronil.

Pregnancy: Pronil is contraindicated in the first trimester of pregnancy. For later trimesters, data in humans are limited; Pronil should be used only if clearly needed and if the potential benefit justifies the potential risk to the fetus, and only under a physician's guidance.

Lactation: Pronil is excreted in breast milk. Breastfeeding is generally not recommended during treatment; when a single dose of Pronil is used, many guidelines advise interrupting breastfeeding for approximately 96 hours (about 4 days) after the dose. Consult a physician before breastfeeding while using Pronil.

Alcohol: Avoid alcohol during treatment with Pronil and for at least 3 days afterward due to the risk of a disulfiram-like reaction (see Interactions).

Blood dyscrasia: Use Pronil with caution in patients with a history of blood dyscrasias; periodic blood counts may be warranted with repeated or prolonged courses.

CNS disease: Use Pronil with caution in patients with active central nervous system disease such as epilepsy, particularly with high-dose or prolonged therapy, given the theoretical risk of neurotoxicity associated with nitroimidazoles.

Hepatic impairment: Dose adjustment (lower dose or extended interval) should be considered in patients with significant hepatic impairment (see Dosage and Administration).

Vulvovaginal candidiasis: Treatment with Pronil for bacterial vaginosis or trichomoniasis may increase the risk of subsequent yeast infection.

Carcinogenicity: Nitroimidazole compounds structurally related to Pronil have shown carcinogenicity in long-term animal studies; the clinical relevance of a single dose of Pronil in humans is unclear, but unnecessary or repeated use should be avoided.

Antimicrobial stewardship: Take Pronil exactly as prescribed by your physician; do not stop, extend, skip doses, or share this medicine with others without medical advice, and use it only for infections proven or strongly suspected to be caused by susceptible organisms.

There is limited clinical experience with overdosage of Pronil. Expected effects of an overdose would generally be an exaggeration of known adverse effects, such as severe nausea, vomiting, abdominal pain, and neurological symptoms (e.g., ataxia, dizziness, or numbness/tingling).

If an overdose of Pronil is suspected, seek immediate medical attention or contact a poison control center. There is no specific antidote; management is supportive and symptomatic, with treatment directed by a physician based on the patient's presentation.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children.

Renal impairment: Specific dose adjustment data for Pronil in renal impairment are limited; use with caution and physician supervision in patients with significant renal disease.

Hepatic impairment: Since Pronil is metabolized in the liver, patients with significant hepatic impairment may require a reduced dose or extended dosing interval (see Dosage and Administration).

Elderly: Data on the use of Pronil in patients 65 years and older are limited; use with caution, taking into account the greater likelihood of decreased hepatic or renal function.

Pediatric patients: Safety and effectiveness of Pronil for bacterial vaginosis and trichomoniasis have been established only in patients 12 years and older; it has not been studied for these indications in children under 12. For amoebiasis and giardiasis, weight-based dosing of Pronil has been used in children in some countries under medical supervision (see Dosage and Administration).

Duration varies by indication: a single dose of Pronil is used for bacterial vaginosis, trichomoniasis, acute intestinal amoebiasis, and giardiasis, while asymptomatic amoebiasis is treated for 3 days and hepatic amoebiasis for 5 days. Always complete the course of Pronil exactly as directed by your physician, even if symptoms improve earlier.

Nitroimidazole antimicrobials; Antiprotozoals; Antibacterials (anti-anaerobic agents).

Secnidazole is reduced intracellularly by susceptible anaerobic and protozoal organisms, generating cytotoxic free radicals and reactive intermediates that damage microbial DNA, causing strand breakage and inhibiting nucleic acid synthesis, which leads to cell death.

Pronil is approved in the United States for bacterial vaginosis and trichomoniasis only in patients 12 years of age and older; safety and effectiveness for these indications have not been established in children under 12 years of age.

Outside the United States, including in Bangladesh, Pronil has also been used in children for intestinal amoebiasis, hepatic amoebiasis, and giardiasis using weight-based dosing (approximately 30–50 mg/kg depending on indication), under the supervision of a physician. Use in young children should always follow specific medical guidance.