Metabolites:

Metabolites are intermediate products (solutes) synthesized or released during metabolism. Based on effect of metabolites on organism, metabolites are divided as primary metabolites and secondary metabolites.

Primary metabolites (nutrient metabolites) are always beneficial to the organism. Eg. Amino acids, vitamins, fat, etc.

Secondary metabolites are harmful to the organism. Secondary metabolites are also called anti-metabolites. Eg. Antibiotics, toxins, enzymes, poisons, etc

Antibiotics:

Antibiotics are anti-metabolites produced by the living cell (micro-organism) to inhibit growth or to kill another organism. Antibiotic is highly active in low concentration however, has adverse or side effects. Antibiotics cannot be synthesized artificially. They have high therapeutic use. Eg. Penicillin, streptomycin, neomycin, etc.