Theophylline is a natural alkaloid derivative of xanthine isolated from the plants Camellia sinensis and Coffea arabica. Theophylline appears to inhibit phosphodiesterase and prostaglandin production, regulate calcium flux and intracellular calcium distribution, and antagonize adenosine. Physiologically, this agent relaxes bronchial smooth muscle, produces vasodilation (except in cerebral vessels), stimulates the CNS, stimulates cardiac muscle, induces […]

The thyroid hormones, triiodothyronine (T3) and its prohormone, thyroxine (T4), are tyrosine-based hormones produced by the thyroid gland that are primarily responsible for regulation of metabolism. Iodine is necessary for the production of T3 and T4. A deficiency of iodine leads to decreased production of T3 and T4, enlarges the thyroid tissue and will cause […]

Tobramycin is an aminoglycoside antibiotic used to treat infections caused by many different bacteria. Tobramycin is usually administered by intravenous infusion, intramuscular injection, or inhalation.

Trimellitic anhydride is a 2-benzofuran compound having oxo groups at the 1- and 3-positions and a carboxy substituent at the 5-position; the cyclic anhydride formed from the carboxy groups at the 1- and 2-positions of trimellitic acid. It has a role as an epitope, an allergen and a hapten. It is a cyclic dicarboxylic anhydride, […]

Trimethoprim (INN) is a bacteriostatic antibiotic used mainly in the prevention and treatment of urinary tract infections. It belongs to the class of chemotherapeutic agents known as dihydrofolate reductase inhibitors. Trimethoprim was formerly marketed by GlaxoSmithKline under trade names including Proloprim, Monotrim, and Triprim; but these trade names have been licensed to various generic pharmaceutical […]

Tryptophan is one of the 20 standard amino acids, as well as an essential amino acid in the human diet. It is encoded in the standard genetic code as the codon UGG. The slight mispronunciation “tWiptophan” can be used as a mnemonic for its single letter IUPAC code W. Only the L-stereoisomer of tryptophan is […]

Tubocurarine Chloride is the chloride salt form of tubocurarine, a naturally occurring curare alkaloid isolated from the bark and stem of Chondodendron tomentosum with a muscle relaxant property. Tubocurarine chloride competes with acetylcholine for the nicotinic receptors at the neuromuscular junction of skeletal muscles, thereby inhibiting the action of acetylcholine and blocking the neural transmission […]

Nadifloxacin is a fluoroquinolone antibiotic that is used topically. It is effective against the Gram-positive bacteria S. aureus and P. acnes, as well as Gram-negative bacteria.

Nalidixic acid (tradenames Nevigramon, Neggram, Wintomylon and WIN 18,320) is the first of the synthetic quinolone antibiotics. In the technical sense, it is a naphthyridone, not a quinolone: its ring structure is a 1,8-naphthyridine nucleus that contains two nitrogen atoms, unlike quinoline, which has a single nitrogen atom.