RETARCILINE

A medication used to treat head lice infections.

Ulesfia (benzyl alcohol) lotion is indicated for the topical treatment of head lice infestation in patients 6 months of age and older.

Lotion does not have ovicidal activity.

G benzathine has an extremely low solubility and, thus, the drug is slowly released from intramuscular injection sites.

The drug is hydrolyzed to penicillin G. This combination of hydrolysis and slow absorption results in blood serum levels much lower but much more prolonged than other parenteral penicillins.

Intramuscular administration of 300,000 units of penicillin G benzathine in adults results in blood levels of 0.03 to 0.05 units per mL, which are maintained for to 5 days.

Similar blood levels may persist for 10 days following administration of 600,000 units and for 14 days following administration of 1,200,000 units.

Blood concentrations of 0.003 units per mL may still be detectable 4 weeks following administration of 1,200,000 units.

Approximately 60% of penicillin G is bound to serum protein.

The drug is distributed throughout the body tissues in widely varying amounts.

Highest levels are found in the kidneys with lesser amounts in the liver, skin, and intestines.

G penetrates into all other tissues and the spinal fluid to a lesser degree.

With normal kidney function, the drug is excreted rapidly by tubular excretion.

In neonates and young infants and in individuals with impaired kidney function, excretion is considerably delayed.

G exerts a bactericidal action against penicillin-susceptible microorganisms during the stage of active multiplication.

It acts through the inhibition of biosynthesis of cell-wall peptidoglycan, rendering the cell wall osmotically unstable.

Penicillin is not active against penicillinase-producing bacteria or against organisms resistant to beta-lactams because of alterations in the penicillin-binding proteins.

Resistance to penicillin G has not been reported in Streptococcus pyogenes.

Penicillin has been shown to be active against most isolates of the following bacteria, both in vitro and in clinical infections as described in the INDICATIONS AND USAGE section.

Gram-positive bacteria

Beta-hemolytic streptococci (groups A, B, C, G, H, L and M).

Benzyl alcohol inhibits lice from closing their respiratory spiracles, allowing the vehicle to obstruct the spiracles and causing the lice to asphyxiate.

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mg/kg (rat, oral) LD50 400 mg/kg IPR-RAT LD50 2000 mg/kg SKN-RBT LD50 53 mg/kg IVN-RAT LD50 2500 mg/kg ORL-GPG LD50.

Prior to administration of this drug, carefully read the WARNINGS, ADVERSE REACTIONS, and DOSAGE AND ADMINISTRATION sections of the labeling.

G benzathine should only be prescribed for the indications listed in this insert.

HYPERSENSITIVITY (ANAPHYLACTIC) REACTIONS HAVE BEEN REPORTED IN PATIENTS ON PENICILLIN THERAPY.

THESE REACTIONS ARE MORE LIKELY TO OCCUR IN INDIVIDUALS WITH A HISTORY OF PENICILLIN HYPERSENSITIVITY AND/OR A HISTORY OF SENSITIVITY TO MULTIPLE ALLERGENS.

THERE HAVE BEEN REPORTS OF INDIVIDUALS WITH A HISTORY OF PENICILLIN HYPERSENSITIVITY WHO HAVE EXPERIENCED SEVERE REACTIONS WHEN TREATED WITH CEPHALOSPORINS.

L-A, CAREFUL INQUIRY SHOULD BE MADE CONCERNING PREVIOUS HYPERSENSITIVITY REACTIONS TO PENICILLINS, CEPHALOSPORINS, OR OTHER ALLERGENS.

OCCURS, BICILLIN L-A SHOULD BE DISCONTINUED AND APPROPRIATE THERAPY INSTITUTED.

SERIOUS ANAPHYLACTIC REACTIONS REQUIRE IMMEDIATE EMERGENCY TREATMENT WITH EPINEPHRINE.

OXYGEN, INTRAVENOUS STEROIDS AND AIRWAY MANAGEMENT, INCLUDING INTUBATION, SHOULD ALSO BE ADMINISTERED AS INDICATED.

Severe cutaneous adverse reactions

Severe cutaneous adverse reactions (SCAR), such as Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP) have been reported in patients taking penicillin G (the active moiety in Bicillin L-A).

SCAR is suspected, Bicillin L-A should be discontinued immediately and an alternative treatment should be considered.

Clostridioides difficile associated diarrhea

Clostridioides difficile associated-diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including Bicillin L-A, and may range in severity from mild diarrhea to fatal colitis.

Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile.

C. difficile produces toxins A and B which contribute to the development of CDAD.

Hypertoxin producing strains of

C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy.

CDAD must be considered in all patients who present with diarrhea following antibacterial use.

Careful medical history is necessary since

CDAD has been reported to occur over two months after the administration of antibacterial agents.

If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued.

Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile, and surgical evaluation should be instituted as clinically indicated.

Do not inject into or near an artery or nerve.

See administration instructions below.

Injection into or near a nerve may result in permanent neurological damage.

Inadvertent intravascular administration, including inadvertent direct intra-arterial injection or injection immediately adjacent to arteries, of Bicillin L-A and other penicillin preparations has resulted in severe neurovascular damage, including transverse myelitis with permanent paralysis, gangrene requiring amputation of digits and more proximal portions of extremities, and necrosis and sloughing at and surrounding the injection site consistent with the diagnosis of Nicolau syndrome.

Such severe effects have been reported following injections into the buttock, thigh, and deltoid areas.

Other serious complications of suspected intravascular administration which have been reported include immediate pallor, mottling, or cyanosis of the extremity both distal and proximal to the injection site, followed by bleb formation; severe edema requiring anterior and/or posterior compartment fasciotomy in the lower extremity.

The above-described severe effects and complications have most often occurred in infants and small children.

Prompt consultation with an appropriate specialist is indicated if any evidence of compromise of the blood supply occurs at, proximal to, or distal to the site of injection. 1–9 FOR DEEP INTRAMUSCULAR INJECTION ONLY.

There have been reports of inadvertent intravenous administration of penicillin G benzathine which has been associated with cardiorespiratory arrest and death.

Therefore, do not inject intravenously or admix with other intravenous solutions. See DOSAGE AND ADMINISTRATION section. Administer by DEEP INTRAMUSCULAR INJECTION ONLY in the upper, outer quadrant of the buttock (dorsogluteal) or the ventrogluteal site.

Quadriceps femoris fibrosis and atrophy have been reported following repeated intramuscular injections of penicillin preparations into the anterolateral thigh.

Because of these adverse effects and the vascularity of this region, administration in the anterolateral thigh is not recommended.

history of a previous hypersensitivity reaction to any of the penicillins is a contraindication.

Streptococcal (Group A) Upper Respiratory.

Infections (for example, pharyngitis) Adults—a single injection of 1,200,000 units; older pediatric patients—a single injection of 900,000 units; infants and pediatric patients under 60 lbs.—300,000 to 600,000 units.

Primary, secondary, and latent—2,400,000 units (1 dose).

Late (tertiary and neurosyphilis)—2,400,000 units at 7-day intervals for three doses.

Congenital—under 2 years of age: 50,000 units/kg/body weight; ages to 12 years: adjust dosage based on adult dosage schedule.

Yaws, Bejel, and Pinta —1,200,000 units (1 injection).

Prophylaxis —for rheumatic fever and glomerulonephritis.

Following an acute attack, penicillin G benzathine (parenteral) may be given in doses of 1,200,000 units once a month or 600,000 units every 2 weeks.

METHOD OF ADMINISTRATION BICILLIN L-A IS INTENDED FOR INTRAMUSCULAR INJECTION ONLY.

DO NOT INJECT INTO OR NEAR AN ARTERY OR NERVE, OR INTRAVENOUSLY OR ADMIX WITH OTHER INTRAVENOUS SOLUTIONS. See WARNINGS SECTION. Administer by DEEP INTRAMUSCULAR INJECTION in the upper, outer quadrant of the buttock (dorsogluteal) or the ventrogluteal site.

In neonates, infants and small children, the midlateral aspect of the thigh may be preferable.

Administration in the anterolateral thigh is not recommended due to the adverse effects observed See WARNINGS section, and vascularity of this region.

When doses are repeated, vary the injection site.

Because of the high concentration of suspended material in this product, the needle may be blocked if the injection is not made at a slow, steady rate.

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration whenever solution and container permit.

L-A (penicillin G benzathine injectable suspension) is supplied in packages of 10 disposable syringes as follows: 1 mL size, containing 600,000 units per syringe, (21 gauge, thin-wall 1-inch needle for pediatric use), with 0.11 mEq of sodium per 600,000 units of penicillin G (2.59 mg of sodium per 600,000 units of penicillin G), NDC 60793-700-10. 2 mL size, containing 1,200,000 units per syringe, (21 gauge, thin-wall 1-1/2-inch needle), with 0.22 mEq of sodium per 1,200,000 units of penicillin G (5.17 mg of sodium per 1,200,000 units of penicillin G), NDC 60793-701-10. 4 mL size, containing 2,400,000 units per syringe (18 gauge, × 1–1/2-inch needle), with 0.45 mEq of sodium per 2,400,000 units of penicillin G (10.32 mg of sodium per 2,400,000 units of penicillin G), NDC 60793-702-10.

Store in a refrigerator, 2° to 8°C (36° to 46°F).

Keep from freezing.

Store in a refrigerator, 2° to 8°C (36° to 46°F).

Keep from freezing.

Teratogenic effects Pregnancy

Reproduction studies performed in the mouse, rat, and rabbit have revealed no evidence of impaired fertility or harm to the fetus due to penicillin G. Human experience with the penicillins during pregnancy has not shown any positive evidence of adverse effects on the fetus.

There are, however, no adequate and well-controlled studies in pregnant women showing conclusively that harmful effects of these drugs on the fetus can be excluded.

Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

Soluble penicillin

G (the hydrolysate of penicillin G benzathine) is excreted in breast milk.

Caution should be exercised when penicillin

G benzathine is administered to a nursing woman.

See INDICATIONS AND USAGE and DOSAGE AND ADMINISTRATION sections..

Clinical studies of penicillin

G benzathine did not include sufficient numbers of subjects aged and over to determine whether they respond differently from younger subjects.

Other reported clinical experience has not identified differences in responses between the elderly and younger patients.

In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function.

Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function.