tetracycline hydrochloride

(tet ra sye' kleen)

Achromycin, Apo-Tetra (CAN), Novo-Tetra (CAN), Nu-Tetra (CAN), Sumycin


Pregnancy Category D


Drug classes




Therapeutic actions

Bacteriostatic: Inhibits protein synthesis of susceptible bacteria, preventing cell replication.



Systemic administration

        Infections caused by rickettsiae; Mycoplasma pneumoniae; agents of psittacosis, ornithosis, lymphogranuloma venereum and granuloma inguinale; Borrelia recurrentis, Haemophilus ducreyi, Yersinia pestis, Yersinia tularensis, Bartonella bacilliformis, Bacteroides, Vibrio cholerae, Campylobacter fetus, Brucella, Escherichia coli, Enterobacter aerogenes, Shigella, Acinetobacter calcoaceticus, Haemophilus influenzae, Klebsiella

        When penicillin is contraindicated, infections caused by Neisseria gonorrhoeae, Treponema pallidum, Treponema pertenue, Listeria monocytogenes, Clostridium, Bacillus anthracis, Fusobacterium fusiforme, Actinomyces

        Adjunct to amebicides in acute intestinal amebiasis

        Uncomplicated urethral, endocervical or rectal infections in adults caused by Chlamydia trachomatis

        Adjunctive therapy for severe acne


Contraindications and cautions

Systemic administration

        Contraindicated with allergy to any of the tetracyclines; pregnancy (toxic to the fetus); lactation (causes damage to the teeth of infant).

        Use cautiously with hepatic or renal dysfunction.


Available forms

Capsules—250, 500 mg; oral suspension—125 mg/5 mL



Systemic administration


1–2 g/day PO in two to four equal doses. Up to 500 mg PO qid.

        Brucellosis: 500 mg PO qid for 3 wk with 1 g streptomycin bid IM the first week and daily the second wk.

        Syphilis: 30–40 g PO in divided doses over 10–15 days (Sumycin); 500 mg PO qid for 15–30 days (all others).

        Uncomplicated gonorrhea: 1.5 g initially, then 500 mg q 6 hr PO to a total of 9 g.

        Gonococcal urethritis: 1.5 g PO initially, then 500 mg q 4–6 hr for 4–6 days.

        Uncomplicated urethral, endocervical, or rectal infections with chlamydia trachomatis: 500 mg qid PO for at least 7 days.

        Severe acne: 1 g/day PO in divided doses; then 125–500 mg/day.



25–50 mg/kg/day PO in four equal doses.








2–4 hr


Metabolism: T1/2: 6–12 hr

Distribution: Crosses placenta; enters breast milk

Excretion: Urine and feces


Adverse effects

Systemic administration

        Dermatologic: Phototoxic reactions, rash, exfoliative dermatitis

        GI: Discoloring and inadequate calcification of primary teeth of fetus if used by pregnant women, discoloring and inadequate calcification of permanent teeth if used during period of dental development, fatty liver, liver failure, anorexia, nausea, vomiting, diarrhea, glossitis, dysphagia, enterocolitis, esophageal ulcers

        Hematologic: Hemolytic anemia, thrombocytopenia, neutropenia, eosinophilia, leukocytosis, leukopenia

        Hypersensitivity: Reactions from urticaria to anaphylaxis, including intracranial hypertension

        Other: Superinfections, local irritation at parenteral injection sites



        Decreased absorption with calcium salts, magnesium salts, zinc salts, aluminum salts, bismuth salts, iron, urinary alkalinizers, food, dairy products, charcoal

        Increased digoxin toxicity

        Increased nephrotoxicity with methoxyflurane

        Decreased effectiveness of hormonal contraceptives, although rare, has been reported with a risk of breakthrough bleeding or pregnancy

        Decreased activity of penicillins


Nursing considerations


        History: Allergy to any of the tetracyclines, tartrazine; hepatic or renal dysfunction, pregnancy, lactation.

        Physical: Site of infection, skin color, lesions; R, adventitious sounds; bowel sounds, output, liver evaluation; urinalysis, BUN, liver and renal function tests.



        Administer oral medication on an empty stomach, 1 hr before or 2–3 hr after meals. Do not give with antacids. If antacids must be used, give them 3 hr after the dose of tetracycline.

        Culture infection before beginning drug therapy.

        Do not administer during pregnancy; drug is toxic to the fetus.

        WARNING: Do not use outdated drugs; degraded drug is highly nephrotoxic and should not be used.

        Arrange for regular renal function tests with long-term therapy.


Teaching points

        Take the drug throughout the day for best results. The drug should be taken on an empty stomach, 1 hr before or 2–3 hr after meals, with a full glass of water. Do not take the drug with food, dairy products, iron preparations, or antacids.

        Finish your complete prescription; if any is left, discard it immediately. Never take an outdated tetracycline product.

        There have been reports of pregnancy occurring when taking tetracycline with hormonal contraceptives. To be certain of avoiding pregnancy, use an additional type of contraceptive.

        This drug should not be used during pregnancy; using barrier contraceptives is advised.

        You may experience these side effects: Stomach upset, nausea (reversible); superinfections in the mouth, vagina (frequent washing may help this problem; if severe, request medication); sensitivity of the skin to sunlight (use protective clothing and a sunscreen).

        Report severe cramps, watery diarrhea, rash or itching, difficulty breathing, dark urine or light-colored stools, yellowing of the skin or eyes.


Adverse effects in Italic are most common; those in Bold are life-threatening.