Fast-M500 mg+100 mg

Fast-M is indicated for the relief of mild-to-moderate pain and fever (analgesic-antipyretic use), with the methionine component included specifically to help protect the liver against paracetamol's dose-dependent hepatotoxic potential.

Established uses

• Relief of mild-to-moderate pain, such as headache, toothache, musculoskeletal pain, and dysmenorrhea.
• Reduction of fever (pyrexia) associated with common infections such as cold and flu.

Adjunct rationale (methionine component)

Methionine is an amino acid precursor of hepatic glutathione. It is combined with paracetamol to help maintain glutathione stores that detoxify paracetamol's minor toxic metabolite, offering a measure of hepatoprotection, particularly relevant if doses are inadvertently exceeded. This does not replace the need for emergency medical treatment in overdose (see Overdose).

Fast-M is not indicated for the treatment of an established paracetamol overdose; specific antidotal therapy (e.g., N-acetylcysteine) administered under medical supervision is required in that situation.

Each tablet/capsule of Paracetamol + Methionine typically contains Paracetamol (Acetaminophen) BP, commonly 500 mg, combined with Methionine BP, commonly 100 mg. Exact strengths vary by manufacturer and formulation; refer to the product label for the specific composition dispensed.

Fast-M is a fixed-dose combination analgesic-antipyretic product. Paracetamol is a widely used, well-established analgesic and antipyretic. Methionine, an essential sulfur-containing amino acid, is added as a hepatoprotective agent because it serves as a precursor for the synthesis of glutathione in the liver, which is involved in detoxifying a minor toxic metabolite of paracetamol. The combination is intended to provide effective symptomatic relief of pain and fever while offering an additional safety margin for liver health.

Fast-M belongs to the therapeutic class of Analgesic and Antipyretic preparations (non-opioid analgesic combination with a hepatoprotective amino acid).

Paracetamol + Methionine combines two components with complementary actions:

• Paracetamol: Exerts analgesic and antipyretic effects primarily through central inhibition of prostaglandin synthesis (cyclo-oxygenase inhibition in the central nervous system) and modulation of the hypothalamic heat-regulating center. It has negligible peripheral anti-inflammatory activity and does not significantly affect platelet function or the gastric mucosa at recommended doses.
• Methionine: An essential amino acid that acts as a metabolic precursor of cysteine and, subsequently, hepatic glutathione. Glutathione is required to conjugate and detoxify N-acetyl-p-benzoquinone imine (NAPQI), the minor toxic metabolite of paracetamol produced via hepatic cytochrome P450 metabolism. By supporting glutathione reserves, methionine is intended to reduce the risk of hepatotoxicity that can occur if paracetamol intake is excessive.

Pharmacokinetically, paracetamol is rapidly and almost completely absorbed from the gastrointestinal tract, extensively metabolized in the liver (mainly by glucuronidation and sulfation, with a minor CYP-mediated pathway producing NAPQI), and excreted primarily in urine as conjugated metabolites. Methionine is absorbed from the small intestine and metabolized via the transsulfuration pathway.

Take Fast-M tablets orally, preferably with a glass of water. May be taken with or without food; taking with food may reduce mild gastric discomfort. Swallow tablets whole; do not crush or chew unless the product is specifically designed as a chewable/dispersible form. Do not take with other paracetamol-containing products.

The following interactions are clinically significant and well-documented for the paracetamol component of Fast-M:

• Warfarin and other oral anticoagulants: Regular, prolonged use of paracetamol may enhance the anticoagulant effect, increasing bleeding risk; occasional use has minimal effect, but INR should be monitored with regular concurrent use.
• Hepatic enzyme inducers (e.g., phenytoin, carbamazepine, rifampicin, chronic alcohol use): Increase production of the toxic paracetamol metabolite (NAPQI), raising the risk of hepatotoxicity even at standard doses.
• Cholestyramine: Reduces absorption of paracetamol if administered within 1 hour of paracetamol; separate dosing is advised.
• Metoclopramide/domperidone: May increase the rate of paracetamol absorption.
• Other paracetamol-containing products: Concurrent use increases the risk of exceeding the maximum daily paracetamol dose and hepatotoxicity; must be avoided.

Fast-M is generally well tolerated at recommended doses. Reported adverse effects include:

• Common/uncommon: Nausea, mild gastric discomfort (more often attributable to the methionine component at higher doses).
• Rare: Hypersensitivity reactions including skin rash, urticaria, angioedema, and, very rarely, severe cutaneous reactions or anaphylaxis.
• Rare: Blood dyscrasias (thrombocytopenia, leukopenia, agranulocytosis) with prolonged paracetamol use.
• Rare: Hepatotoxicity, primarily a risk with overdose or chronic excessive use rather than at recommended therapeutic doses (see Overdose).

Pregnancy: Paracetamol, the principal component of Fast-M, is widely used in pregnancy at recommended doses when clinically needed and is generally considered acceptable for short-term use; however, as with any medicine in pregnancy, Fast-M should be used only if clearly needed, at the lowest effective dose for the shortest duration, and only after consulting a physician, since data specific to the combination product (including the methionine component) in pregnancy are limited.

Lactation: Paracetamol passes into breast milk in small amounts generally considered compatible with breastfeeding at recommended doses. Data on methionine supplementation during lactation are limited. Fast-M should be used during breastfeeding only if the potential benefit justifies the potential risk, and a physician should be consulted before use.

The following precautions apply to the use of Fast-M:

• Do not exceed the maximum recommended daily dose of paracetamol; doing so risks severe, potentially fatal liver damage. Methionine does not eliminate this risk and must never be relied upon to justify exceeding recommended doses.
• Avoid concurrent use of any other paracetamol-containing product (including cold/flu remedies) to prevent inadvertent overdose.
• Use with caution in patients with pre-existing liver disease, chronic alcohol use/dependence, malnutrition, dehydration, or chronic malnourishment, all of which increase susceptibility to hepatotoxicity (see Contraindications for severe hepatic impairment).
• Use with caution in renal impairment; dosing interval may need to be extended.
• Seek medical advice if pain persists for more than a few days, if fever persists for more than 3 days, or if symptoms worsen, as this may indicate a condition requiring different treatment.
• This product is not an antibiotic and has no role in treating bacterial infections.

Overdose of Fast-M is a medical emergency, driven primarily by the paracetamol component, and can cause severe, potentially fatal hepatotoxicity (and, less commonly, renal impairment) even though methionine is included to provide some protective effect — this protection is limited and unreliable in overdose.

Early symptoms (first 24 hours) may be minimal or include nausea, vomiting, abdominal pain, and pallor; liver damage may not become clinically apparent for 1–4 days.

Seek immediate medical attention or contact emergency services/poison control even if the patient feels well, as early treatment (e.g., with N-acetylcysteine, guided by blood paracetamol levels and timing) significantly improves outcomes. Do not attempt to treat a suspected overdose at home.

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

Elderly: Use at the lowest effective dose; monitor for reduced hepatic/renal reserve.

Hepatic impairment: Use with caution at reduced dose/frequency in mild-to-moderate impairment; contraindicated in severe hepatic impairment (see Contraindications).

Renal impairment: Extend the dosing interval in significant renal impairment.

Chronic alcohol users: Increased risk of hepatotoxicity even at standard doses of Fast-M; use with caution and consider a lower maximum daily dose.

Pregnancy and lactation: See Pregnancy and Lactation section.

Fast-M is intended for short-term, symptomatic use. For pain, do not use for more than 5 days without medical advice; for fever, do not use for more than 3 days without medical advice. If symptoms persist or worsen, consult a physician, as continued self-treatment may mask an underlying condition requiring specific therapy.

Non-opioid analgesic and antipyretic combination (paracetamol) with a hepatoprotective amino acid adjunct (methionine).

Paracetamol acts centrally to inhibit prostaglandin synthesis and reset the hypothalamic thermoregulatory set-point, producing analgesic and antipyretic effects without significant peripheral anti-inflammatory action. Methionine is metabolized via the transsulfuration pathway to cysteine, a rate-limiting substrate for hepatic glutathione synthesis; adequate glutathione stores allow conjugation and safe elimination of NAPQI, the minor toxic metabolite generated during paracetamol metabolism, thereby offering a degree of hepatoprotection in Paracetamol + Methionine.

Safety and efficacy of the fixed-dose combination Fast-M specifically have not been well established in children under 12 years, and this product is generally not recommended for that age group. Where paracetamol is needed in children, weight-based, age-appropriate paediatric paracetamol formulations should be used instead, under a physician's or pharmacist's guidance. In adolescents 12 years and above, adult dosing of Fast-M may be used with the same precautions that apply to adults.