Gamma Benzene Hexachloride (Lindane)

Usage

• Gamma Benzene Hexachloride (GBH), also known as Lindane, is prescribed for the treatment of scabies (infestation with the mite Sarcoptes scabiei) and pediculosis (lice infestation). It is an insecticide and acts as a scabicide and pediculicide.
• Pharmacological Classification: Antiparasitic, Ectoparasiticide.
• Mechanism of Action: GBH penetrates the exoskeleton of parasites (mites and lice) and stimulates their nervous systems, leading to seizures and death. It also has ovicidal activity.

Alternate Names

• Lindane
• Gamma-hexachlorocyclohexane (γ-HCH)
• Kwell, G-Well (brand names)
• Scabi, Gambex, Quellada (brand names)

How It Works

• Pharmacodynamics: GBH targets the nervous system of parasites, causing hyperexcitation and death. It is directly absorbed through the exoskeleton of mites and lice. In humans, systemic absorption can occur, especially with prolonged or excessive application, leading to neurotoxic effects.
• Pharmacokinetics: Approximately 10% of topically applied lindane is absorbed systemically. Absorption is enhanced by oils and damaged skin. It is metabolized in the liver and excreted primarily in the urine.
• Mode of Action: GBH acts by interfering with neuronal membrane function in the parasite. While the exact mechanism is not fully elucidated, it is thought to disrupt GABA-mediated chloride channels, leading to uncontrolled neuronal firing.
• Elimination Pathways: Primarily renal excretion after hepatic metabolism.

Dosage

Standard Dosage

Adults:

• Scabies: Apply a thin layer of 1% lotion or cream to the entire body from the neck down, including the soles of the feet. Wash off thoroughly after 8-12 hours. Up to 60ml may be needed for larger individuals.
• Pediculosis (Head Lice): Apply 1-2 oz (30-60 ml) of 1% shampoo to dry hair. Leave on for 4 minutes, lather with water, rinse thoroughly, and remove nits with a fine-toothed comb.

Children:

• Scabies: Similar to adult dosing, adjusting the amount based on body size (e.g., half of a 2-ounce container for children under 6 years). Do not apply to the face.
• Pediculosis: Similar to adult dosing, but do not exceed 2 oz. of shampoo.

Special Cases:

• Elderly Patients: Use with caution due to increased risk of neurotoxicity. Lower doses may be considered.
• Patients with Renal Impairment: Caution is advised, although specific dose adjustments are not well-defined.
• Patients with Hepatic Dysfunction: Use with caution, as GBH is metabolized in the liver.
• Patients with Comorbid Conditions: Use with extreme caution in patients with pre-existing seizure disorders, HIV, head trauma, CNS tumors, severe hepatic cirrhosis, or those using medications that lower the seizure threshold.

Clinical Use Cases

GBH is not typically used in the settings listed (Intubation, Surgical Procedures, Mechanical Ventilation, ICU Use, Emergency Situations). Its use is limited to topical treatment of scabies and lice.

Dosage Adjustments

Dose adjustments are based primarily on body size and age. Patients with a history of seizures or other neurological conditions should avoid GBH.

Side Effects

Common Side Effects

• Skin irritation, burning, itching, dryness, rash at the application site
• Dizziness

Rare but Serious Side Effects

• Seizures
• Aplastic anemia
• Neurotoxicity (ataxia, headache, restlessness, paresthesia)

Long-Term Effects

• Chronic skin irritation
• Potential for hematological effects with prolonged use

Adverse Drug Reactions (ADR)

• Seizures, neurotoxicity, aplastic anemia

Contraindications

• Premature infants
• Uncontrolled seizure disorders
• Hypersensitivity to GBH
• Broken or severely inflamed skin
• Patients weighing less than 50kg

Drug Interactions

• Drugs that lower the seizure threshold (antidepressants, antipsychotics) may increase the risk of seizures.
• Oils and oil-based products can increase absorption and toxicity of GBH.

Pregnancy and Breastfeeding

• Pregnancy Safety Category: C (Animal studies showed adverse effects. Data in pregnant women limited.) GBH should generally be avoided during pregnancy.
• Breastfeeding: GBH can be excreted in breast milk. It is generally not recommended during breastfeeding.

Drug Profile Summary

• Mechanism of Action: Disrupts neuronal function in parasites, leading to their death.
• Side Effects: Skin irritation, dizziness, seizures (rare).
• Contraindications: Premature infants, seizure disorders, hypersensitivity.
• Drug Interactions: Drugs lowering seizure threshold, oils.
• Pregnancy & Breastfeeding: Generally avoided.
• Dosage: Apply thinly to affected area for scabies (8-12 hours) or as shampoo for lice (4 minutes).
• Monitoring Parameters: Observe for signs of skin irritation or neurotoxicity.

Popular Combinations

GBH is not generally used in combination with other drugs.

Precautions

• General Precautions: Avoid contact with eyes and mucous membranes. Do not apply to broken skin.
• Specific Populations: Avoid use in premature infants, pregnant or breastfeeding women, and patients with seizure disorders. Use with caution in children, the elderly, and individuals weighing <50 kg.
• Lifestyle Considerations: No specific lifestyle restrictions.

FAQs (Frequently Asked Questions)

Q1: What is the recommended dosage for Gamma Benzene Hexachloride?

A: For scabies, apply a thin layer to the skin from the neck down and wash off after 8-12 hours. For lice, apply 1-2 oz of shampoo to dry hair for 4 minutes, then lather and rinse.

Q2: What are the common side effects of Gamma Benzene Hexachloride?

A: Common side effects include skin irritation, itching, burning, and dryness at the application site, as well as dizziness.

Q3: Is Gamma Benzene Hexachloride safe to use during pregnancy?

A: GBH is generally avoided during pregnancy due to potential risks to the fetus. Consult a physician for alternatives.

Q4: Can Gamma Benzene Hexachloride be used in children?

A: It can be used in children, but with caution and under the supervision of a physician. Dosage should be adjusted based on body size.

Q5: What are the contraindications for Gamma Benzene Hexachloride?

A: Contraindications include premature infants, uncontrolled seizure disorders, hypersensitivity to GBH, and broken skin.

Q6: How does Gamma Benzene Hexachloride work?

A: GBH penetrates the exoskeleton of parasites, affecting their nervous systems and causing seizures and death.

Q7: What should I do if I accidentally ingest Gamma Benzene Hexachloride?

A: Seek immediate medical attention.

Q8: Can Gamma Benzene Hexachloride be used for other conditions besides scabies and lice?

A: GBH is only indicated for the treatment of scabies and lice.

Q9: How long does it take for Gamma Benzene Hexachloride to work?

A: A single application is usually sufficient to eradicate scabies and lice, but post-treatment itching can persist.