Banned Drugs: Chloramphenicol & Nitrofurans

What are chloramphenicol (CAP) and nitrofurans (NF)?

Chloramphenicol

Highly effective and well-tolerated broad-spectrum antibiotic. It is an antibiotic first isolated from Streptomyces venequelae in 1947 but now produced synthetically

Nitrofurans

Group of broad spectrum antibiotics and antiprotozoa. The common nitrofurans are furazolidone (AOZ), furaltadone (AMOZ), nitrofurantoin (AHD) and nitrofurazone (SC). Nitrofurans are quickly metabolized in animals but the tissue-bound nitrofuran metabolites are detectable for a long time after administration. AOZ, AMOZ, AHD and SEM (SC), which are commonly tested, are the metabolites of the nitrofuran parent drugs.

How do CAP and NF work?

Chloramphenicol

CAP inhibits the synthesis of protein and is mainly bacteriostatic. Mechanism of the action of inhibition includes the interruption of peptide-chain elongation, the blocking of the A site of ribosomes, the misreading of the genetic code or the prevention of the attachment of oligosaccharide side chains to glycoproteins

Nitrofurans

Nitrofurans inhibit a number of microbial enzyme systems, including those involved in carbohydrate metabolism, and they also block the initiation of translation.

Laws and Regulations on CAP and NF
As these drugs have a broad spectrum of activity against bacteria, they may be misused in food-producing animals such as poultry, livestock, honey bees and aquaculture products mainly shrimp.

CAP and NF are banned drugs under Malaysian Food Act 1983 (Malaysia), Food and Drug Administration (USA), Canadian Health Protection Branch (Canada) and EU requirements on residues of veterinary medicines (European countries).

Is there any maximum residue limit (MRL) for CAP and NF?
There is NO maximum residue limit for CAP and NF/ NF metabolites. They should not be detected in food products at all, regardless of concentration.

Common specimens which require CAP and NF tests

Chloramphenicol – Meat or muscle, egg, milk and honey

Nitrofurans – Meat or muscle, feed and egg

The adverse effects of CAP and NF on humans

Chloramphenicol

  • Aplastic anaemia (bone marrow ceases to produce sufficient red and white blood cells, as well as platelets)*
  • Hypersensitivity reactions, gastrointestinal complaints and neurological complications after long-term treatment
    Note:* due to therapeutic treatment courses with CAP

Nitrofurans

  • Carcinogenic
  • Mutagenic