For the use of a Registered Medical Practitioner, Hospital or Laboratory only.
1. Description
Oxitres is the acetylated derivative of the amino acid L-cysteine. Acetylcysteine is the precursor to glutathione, one of the body’s most powerful antioxidants which prevents cellular damage. It prevents accumulation of free radicals inside our cells. N-acetyl cysteine provides the cysteine component for the production of glutathione in the body’s cells to protect cells and organs and to help regulate immune response.
2. Composition
Each tablet contains N-Acetylcysteine USP 600 mg
3. Dosage Form
Tablet
4. Pharmacology
Pharmacodynamics
Acetylcysteine (N-acetylcysteine, NAC) is an acetylated derivative of the amino acid L-cysteine. It serves as a precursor for the synthesis of glutathione (GSH), one of the body’s principal endogenous antioxidants. By replenishing intracellular glutathione stores, NAC protects cells against oxidative stress and free radical-induced injury.
The free sulfhydryl (-SH) group of acetylcysteine also directly scavenges reactive oxygen species (ROS), thereby reducing oxidative damage. In patients with chronic kidney disease (CKD), oxidative stress is increased during conditions such as haemodialysis, peritoneal dialysis, administration of intravenous iron, and exposure to radiographic contrast media. NAC helps reduce oxidative stress and may provide renoprotective and cardioprotective effects.
Pharmacokinetics
Absorption
Following oral administration, acetylcysteine is rapidly absorbed from the gastrointestinal tract. Peak plasma concentrations are reached approximately 1 hour after dosing. Due to extensive first-pass metabolism, the oral bioavailability is relatively low (approximately 4–10%). Despite this, oral acetylcysteine effectively increases systemic glutathione levels.
Distribution
Acetylcysteine is rapidly distributed to various tissues after absorption. It readily enters cells, where it is deacetylated to L-cysteine, the rate-limiting precursor for glutathione synthesis. It is incorporated into intracellular proteins and peptides involved in antioxidant defense.
Metabolism
Acetylcysteine undergoes extensive metabolism in the intestinal mucosa and liver, where it is deacetylated to L-cysteine. L-cysteine is subsequently utilised for the synthesis of glutathione and other sulfur-containing compounds. The biological activity of acetylcysteine is primarily attributed to its free sulfhydryl group and its ability to increase intracellular glutathione concentrations.
Elimination
Acetylcysteine and its metabolites are eliminated primarily through the kidneys. Plasma concentrations decline rapidly after administration, and the parent compound is generally undetectable approximately 12 hours after an oral dose. Metabolites are excreted mainly in the urine, with a small proportion eliminated in the faeces.
5. Indications
NAC is mainly indicated in:
- IV iron administration as Oxidative stress occurs rapidly with infusion of intravenous iron sucrose in patients with CKD.
- Peritoneal Dialysis as the reactive oxygen species (ROS) generated by conventional PD solution (PDS) mediate functional and structural alterations of peritoneal membrane causing peritoneal fibrosis.
- Haemodialysis as patients show an increase in generation of ROS during the process and NAC may help lower plasma homocysteine concentration. Patients with chronic renal failure, diabetes mellitus and heart failure have impaired nitric oxide activity, which could account for their susceptibility to develop contrast media nephrotoxicity (CIN).
- N-Acetylcysteine (Oxitres) acts as an antioxidant.
Uses of N-Acetylcysteine
Acute Kidney Failure: Radio contrast agents are given to patients before medical imaging to enhance image clarity or to highlight a specific organ or other internal structure.
Patients with kidney disease are at increased risk of acute kidney failure; sometimes connected with this procedure, a condition called radiocontrast nephropathy. Evidence for N-acetylcysteine in preventing contrast-induced nephropathy is mixed: the large PRESERVE trial (Weisbord SS et al., N Engl J Med 2018;378:603–614) found no benefit of oral acetylcysteine over placebo.
Protects the Heart: NAC helps improve the blood vessel function in people suffering from high blood pressure and diabetes, and thus preventing cardiovascular complications.
Protect the Kidneys: Kidney damage in diabetes can be prevented attenuated by supplementation with NAC.
6. Contraindications
Oxitres is contraindicated in patients with:
Known hypersensitivity to acetylcysteine or to any component of the formulation.
History of allergic or anaphylactic reactions to acetylcysteine.
7. Precautions
Pregnancy: Studies in pregnant women are inadequate. Therefore, NAC should be used with caution during pregnancy and only if clearly indicated.
8. Drug Interactions
- Nitroglycerin: concomitant use may cause significant hypotension and enhanced headache.
- Activated charcoal may reduce the absorption of N-acetylcysteine.
- Oral antibiotics (e.g., tetracyclines, penicillins, cephalosporins): separate doses by at least 2 hours.
9. Adverse Effects
NAC is generally safe and well tolerated even at high doses. The most common side effects associated with high oral doses are nausea, vomiting and other gastrointestinal disturbances. Therefore, oral administration is contraindicated in persons with active peptic ulcer. Infrequently, anaphylactic reactions due to histamine release occurs and can consist of rash, pruritus, angioedema, bronchospasm, tachycardia and changes in blood pressure.
10. Dosage & Administration
The typical oral dose for NAC:
- Haemodialysis – 600 mg a Day to 600 mg BID
- Peritoneal Dialysis – 1200 mg BID
- IV Iron Administration – 600 mg BID 10 Days Prior to Therapy
11. Overdosage
No data available.
12. Storage
Store in a dry place at a temperature not exceeding 30°C. Protect from light. Keep the medicine out of reach of children.
Additional Information
Mode of Action
NAC acts as an antioxidant by direct action against reactive oxygen species or by improving the body’s natural antioxidant availability of glutathione. Glutathione detoxifies chemicals, regulates cell proliferation, stores and transports cysteine and regulates the immune response.
Additional pharmacokinetic information
NAC is a sulfhydryl-containing compound, rapidly absorbed into various tissues following an oral dose, deacetylated and metabolized in the intestines as well as liver and its metabolites incorporated into proteins and peptides. Peak plasma levels of NAC occur approximately one hour after an oral dose; at 12 hours post-dose it is undetectable in plasma. Despite a relatively low bioavailability of only 4-10 percent, oral administration of NAC appears to be clinically effective. The biological activity of NAC is attributed to its sulfhydryl group, while its acetyl substituted amino group affords it protection against oxidative and metabolic processes. NAC administration is an effective method of increasing plasma glutathione (GSH) levels, as incorporation of cysteine into GSH appears to be the rate-limiting step in GSH synthesis.
13. Presentation
10 tablets in a strip, 10 strips in a Box.