Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ACHROMYCIN vs ACTICLATE CAP
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Tetracycline antibiotic that inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit, preventing aminoacyl-t RNA from binding to the A site.
Inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit, blocking aminoacyl-t RNA binding.
Infections caused by susceptible strains of bacteria (e.g., Mycoplasma pneumoniae, Chlamydia trachomatis, Rickettsia species),Acne vulgaris,Periodontitis (as adjunctive therapy),Off-label: Chronic obstructive pulmonary disease exacerbations, malaria prophylaxis
Treatment of infections caused by susceptible bacteria, including respiratory tract infections, urinary tract infections, and acne vulgaris
250-500 mg orally every 6 hours or 500 mg intravenously every 12 hours.
350 mg orally once daily, increased to 350 mg twice daily if no response after 2 weeks.
6-12 hours; prolonged to 48-72 hours in severe renal impairment
Terminal elimination half-life 6-10 hours; prolonged in renal impairment (up to 22 hours in anuria)
Primarily renally excreted unchanged; minimal hepatic metabolism.
Primarily hepatic; metabolites include 4-epimino derivatives; not significantly metabolized via CYP450.
Renal (60-80% unchanged via glomerular filtration); biliary/fecal (10-20%)
Renal (60-70% as unchanged drug), fecal (20-30% as metabolites); minor biliary elimination
50-60% bound to serum proteins
90-95% bound to serum proteins, primarily albumin
1.5-2.0 L/kg; indicates extensive tissue penetration
0.75 L/kg (50-70 L in adults); distributes well into tissues including bone, teeth, and synovial fluid
Oral: 75-80%; Topical: minimal systemic absorption
Oral: 90-100% (capsule); food or dairy reduces absorption by up to 50%
GFR 50-80 m L/min: no adjustment; GFR 10-50 m L/min: administer every 12-24 hours; GFR <10 m L/min: administer every 24 hours or avoid.
e GFR 30-59 m L/min: 350 mg once daily; e GFR <30 m L/min: not recommended.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: avoid use.
Child-Pugh A: no adjustment; Child-Pugh B or C: 175 mg once daily.
25-50 mg/kg/day orally divided every 6 hours; maximum 2 g/day.
Not established for children <12 years; for ≥12 years, same as adult dosing.
Initiate at lower end of dosing range due to age-related renal function decline; monitor renal function.
Initiate at 175 mg once daily; titrate cautiously based on renal function.
No FDA boxed warning
Photosensitivity: severe sunburn can occur with sun exposure; discontinue if photosensitivity occurs. Tooth development: use during tooth development (last half of pregnancy, infancy, childhood to age 8) may cause permanent tooth discoloration. Bone growth: may retard bone growth in premature infants. Renal toxicity: may cause azotemia, hyperphosphatemia, and acidosis. Avoid in renal impairment.
Photosensitivity reactions,Esophageal ulceration if taken with insufficient fluids,Pseudotumor cerebri in adults,Pancreatitis,Hepatotoxicity,Renal impairment (accumulation may worsen renal function),Superinfection with resistant organisms
Photosensitivity, tooth discoloration, bone growth retardation, renal impairment, hepatotoxicity, increased intracranial pressure, superinfection, and use in pregnancy/lactation.
Hypersensitivity to tetracyclines,Pregnancy (second and third trimesters) due to fetal harm,Children under 8 years due to permanent tooth discoloration and enamel hypoplasia,Severe hepatic or renal impairment
Hypersensitivity to tetracyclines, pregnancy, breastfeeding, children under 8 years, renal impairment, and concurrent use with oral retinoids.
Avoid dairy products (milk, cheese, yogurt) within 2-3 hours of taking Achromycin, as calcium binds tetracycline and reduces absorption. Also avoid iron-fortified foods, calcium-fortified juices, and high-calcium meals. Take on an empty stomach with a full glass of water; food, especially dairy, decreases absorption by up to 50%.
Avoid food and beverages for at least 1 hour before and after administration, as they can reduce the efficacy of activated charcoal. Do not mix with milk or ice cream, as they decrease binding capacity. Administer with water or a non-carbonated, non-alcoholic drink.
ACHROMYCIN (tetracycline) is classified as FDA Pregnancy Category D. First trimester: Associated with minor malformations, but risk is low. Second and third trimesters: Exposure can cause permanent discoloration of deciduous teeth (yellow-gray-brown) due to deposition during calcification, and reversible inhibition of bone growth. Avoid use after the fourth month of pregnancy. Risk of maternal hepatotoxicity if used intravenously in pregnancy.
First trimester: Category D; tetracyclines can cause fetal harm including inhibited bone growth and discoloration of teeth (yellow-gray-brown). Second and third trimesters: Known to cause permanent tooth discoloration (enamel hypoplasia) and reversible inhibition of bone growth; use contraindicated after 15 weeks gestation.
Tetracycline is excreted into breast milk in low concentrations. Theoretical risk of dental discoloration and bone growth suppression in nursing infants, but levels are usually below therapeutic. M/P ratio is approximately 0.5-0.8. Use with caution, especially in infants with prolonged exposure. American Academy of Pediatrics considers tetracyclines compatible with breastfeeding.
Tetracyclines are excreted in breast milk but absorption by the infant is limited due to chelation with milk calcium; M/P ratio for doxycycline is approximately 0.3-0.4. Theoretical risk of tooth staining and bone inhibition, but clinical significance is low with short-term use; caution with prolonged therapy.
No dosage adjustment is recommended for pregnancy; however, use is contraindicated after the first trimester due to risks to the fetus. If essential, use the lowest effective dose for the shortest duration. Intravenous doses should be cautious due to risk of hepatotoxicity; reduce dose in renal impairment.
No dosage adjustment is typically recommended for doxycycline in pregnancy due to minimal pharmacokinetic changes; however, use is generally avoided in the second and third trimesters. If indicated, standard dosing may be used in the first trimester with caution.
Achromycin (tetracycline) should be administered on an empty stomach (1 hour before or 2 hours after meals) to ensure adequate absorption. Avoid concurrent use with dairy products, antacids, iron, calcium, magnesium, or bismuth subsalicylate as they chelate tetracycline and reduce absorption. Tetracycline can cause photosensitivity; advise patients to avoid prolonged sun exposure and use sunscreen. It is contraindicated in pregnancy (risk of hepatotoxicity and fetal bone/teeth discoloration), lactation, and children under 8 years (permanent tooth discoloration and bone growth inhibition). Monitor for signs of superinfection, especially Clostridium difficile-associated diarrhea. Tetracycline may increase the effect of warfarin; monitor INR closely.
ACTICLATE CAP is a high-dose activated charcoal formulation used for acute poisoning or overdose. Administer within 1 hour of ingestion for optimal efficacy. Do not use in patients with impaired consciousness unless the airway is protected. Monitor for vomiting and ensure rapid administration via nasogastric tube if necessary. Not effective for alcohols, metals, or caustics.
Take this medication on an empty stomach, at least 1 hour before or 2 hours after meals.,Do not take with dairy products, antacids, iron supplements, or calcium supplements; separate by at least 2-3 hours.,Avoid excessive sunlight or tanning beds; use sunscreen and wear protective clothing to prevent severe sunburn.,Complete the full course of treatment even if you feel better; do not skip doses.,Notify your doctor immediately if you develop watery or bloody diarrhea, rash, headache, blurred vision, or signs of infection worsening.,Do not use if you are pregnant, planning to become pregnant, or breastfeeding; this medication can harm the unborn baby or nursing infant.,Keep out of reach of children; expired tetracycline can cause kidney damage.
Take ACTICLATE CAP only if directed by a healthcare professional after a poisoning or overdose.,This medication is not for regular use; it is a one-time emergency treatment.,Avoid taking this with food or drinks; take on an empty stomach for best absorption of toxins.,You may experience black stools or vomiting; this is normal.,Seek immediate medical attention if you have trouble swallowing, severe vomiting, or signs of bowel obstruction.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ACHROMYCIN vs ACTICLATE CAP, answered by our medical review team.
ACHROMYCIN is a Tetracycline Antibiotic that works by Tetracycline antibiotic that inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit, preventing aminoacyl-t RNA from binding to the A site.. ACTICLATE CAP is a Tetracycline Antibiotic that works by Inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit, blocking aminoacyl-t RNA binding.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ACHROMYCIN and ACTICLATE CAP depend on the specific clinical indication. These are both Tetracycline Antibiotic agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of ACHROMYCIN is: 250-500 mg orally every 6 hours or 500 mg intravenously every 12 hours.. The standard adult dose of ACTICLATE CAP is: 350 mg orally once daily, increased to 350 mg twice daily if no response after 2 weeks.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between ACHROMYCIN and ACTICLATE CAP in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. ACHROMYCIN is classified as Category C. ACHROMYCIN (tetracycline) is classified as FDA Pregnancy Category D. First trimester: Associated with minor malformations, but risk is low. Second and third trimesters: Exposure ca. ACTICLATE CAP is classified as Category C. First trimester: Category D; tetracyclines can cause fetal harm including inhibited bone growth and discoloration of teeth (yellow-gray-brown). Second and third trimesters: Known t. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.