Pyrethrum Extract

For the treatment of head, body, or pubic lice in adults, the dosage is determined by the amount of product needed to completely saturate the affected area.

• Head Lice: Apply a sufficient quantity (typically 1 to 2 ounces depending on hair length) to dry hair and scalp. The hair must be completely wet with the product.
• Pubic Lice: Apply to the pubic hair and surrounding skin until the area is thoroughly saturated.
• Body Lice: After a thorough cleaning of the body, apply to the affected skin areas. Note that for body lice, clothing and bedding must also be treated or discarded as the parasites live in the fabric.

Pyrethrum Extract is generally considered safe for children, but age restrictions apply:

• Children 2 Years and Older: Use the same application method as adults, ensuring the product does not get into the child's eyes, nose, or mouth.
• Infants under 2 Years: Safety and efficacy have not been established. Do not use Pyrethrum Extract on infants without direct consultation with a pediatrician.
• Children with Asthma: Use with extreme caution, as the botanical nature of the extract can trigger respiratory reactions.

Renal Impairment

No dosage adjustment is required for patients with kidney disease, as systemic absorption is minimal. However, patients should avoid extensive application to broken skin.

Hepatic Impairment

No dosage adjustment is required for patients with liver disease for topical use.

Elderly Patients

No specific dosage adjustments are needed for geriatric patients; however, caregivers should assist with application to ensure thorough coverage and to prevent accidental slips in the shower or falls during the rinsing process.

Proper application is critical for the success of the treatment:

1. 1Apply to Dry Hair: Unlike regular shampoo, Pyrethrum Extract should be applied to completely dry hair. Water can dilute the medication and reduce its effectiveness.
2. 2Saturation: Use enough product to ensure the hair and skin are soaking wet. Pay special attention to the area behind the ears and the nape of the neck.
3. 3Wait Time: Leave the medication on the hair or skin for exactly 10 minutes. Do not leave it on longer, as this increases the risk of skin irritation without increasing the kill rate.
4. 4Rinse: Add a small amount of warm water, form a lather, and rinse thoroughly.
5. 5Nit Removal: While the hair is damp, use a fine-tooth 'nit comb' to remove dead lice and eggs. This is a crucial step for aesthetic and diagnostic purposes.
6. 6The Second Treatment: You MUST repeat the entire process in 7 to 10 days. This is non-negotiable, as the first treatment does not kill unhatched eggs.

If you forget to perform the second treatment on day 7, perform it as soon as you remember. If more than 10-12 days have passed since the first treatment, newly hatched lice may have already begun laying new eggs, and you may need to restart the entire two-dose cycle. Consult your doctor for guidance.

Overdose via topical application is rare but can lead to severe skin irritation or chemical burns.

• Signs of Accidental Ingestion: Nausea, vomiting, tremors, dizziness, or seizures.
• Emergency Measures: If swallowed, call a Poison Control Center (1-800-222-1222 in the USA) or seek emergency medical attention immediately. Do not induce vomiting unless told to do so by a professional.

> Important: Follow your healthcare provider's dosing instructions. Do not adjust your dose or application frequency without medical guidance.

Most patients tolerate Pyrethrum Extract well, but localized skin reactions are common due to the nature of the chemical action and the presence of the synergist. Common side effects include:

• Pruritus (Itching): Many patients experience increased itching immediately after application. This is often a reaction to the lice dying or a mild irritant effect of the shampoo.
• Erythema (Redness): The skin or scalp may appear slightly red or flushed for several hours after treatment.
• Mild Burning Sensation: A slight tingling or warm sensation on the scalp is frequently reported.

These effects are usually transient and should resolve within 24 hours of rinsing the product.

• Contact Dermatitis: Some individuals may develop a localized rash or small bumps at the site of application. This is more common in individuals with sensitive skin.
• Xeroderma (Dry Skin): The alcohols or surfactants in the formulation can strip natural oils, leading to temporary dryness or flaking of the scalp.
• Edema (Swelling): Mild swelling of the scalp or forehead may occur in sensitive individuals.

• Anaphylaxis: A severe, life-threatening allergic reaction is rare but possible, particularly in those with known flower allergies.
• Paresthesia: Numbness or a 'pins and needles' sensation that persists beyond the initial treatment period.
• Corneal Irritation: If the product accidentally enters the eyes, it can cause severe pain, redness, and temporary blurred vision.

> Warning: Stop using Pyrethrum Extract and call your doctor immediately if you experience any of these symptoms:

• Difficulty Breathing: Wheezing, shortness of breath, or a feeling of chest tightness (this may indicate a cross-reaction in patients with asthma).
• Severe Swelling: Swelling of the face, lips, tongue, or throat.
• Hives: A widespread, itchy, red rash that spreads beyond the area of application.
• Seizures: Though extremely rare and usually associated with ingestion, any neurological changes require emergency care.
• Severe Skin Blistering: If the scalp or skin begins to blister or peel significantly.

Pyrethrum Extract is not intended for long-term or chronic use. Prolonged or repeated use beyond the recommended two-dose schedule can lead to:

• Chronic Dermatitis: Persistent inflammation of the skin.
• Lice Resistance: Overuse can contribute to the development of 'super lice' that are no longer susceptible to pyrethrins.
• Sensitization: Repeated exposure may cause an individual to develop an allergy to the substance where none previously existed.

There are currently no FDA Black Box Warnings for Pyrethrum Extract. However, it is strictly labeled for external use only. Use on the eyelashes or eyebrows requires a specific medical diagnosis, as the risk of ocular toxicity is high. If lice are found on the eyelashes, a specialized ophthalmic ointment (usually petroleum-based) is often preferred over Pyrethrum Extract.

Report any unusual symptoms or persistent irritation to your healthcare provider. If skin irritation persists after the treatment is washed off, a mild topical steroid or antihistamine may be recommended by your doctor.

Pyrethrum Extract is a potent chemical agent and must be handled with care. It is for external use only. It must never be swallowed, inhaled, or applied to mucous membranes (the inside of the nose, mouth, or vagina). Always wash your hands thoroughly after applying the medication to yourself or someone else.

No FDA black box warnings for Pyrethrum Extract.

• Allergic Reactions / Anaphylaxis Risk: This is the most significant warning for Pyrethrum Extract. Because it is derived from Chrysanthemums, there is a high risk of cross-sensitivity. If you are allergic to ragweed, marigolds, daisies, or sunflowers, you are at a much higher risk of a severe allergic reaction to Pyrethrum Extract.
• Asthma and Respiratory Risks: There have been documented cases of Pyrethrum Extract triggering asthma attacks or causing difficulty breathing in sensitive individuals, even when applied topically. This is likely due to the inhalation of vapors during the application process.
• Ocular Toxicity: This medication is highly irritating to the eyes. If contact occurs, the eyes should be flushed with large amounts of water for at least 15 minutes. If irritation persists, an urgent ophthalmological exam is required.
• Infection Risk: Lice infestations often cause intense itching, leading to scratching that breaks the skin. Do not apply Pyrethrum Extract to skin that is raw, oozing, or shows signs of secondary bacterial infection (such as pus or crusting) without consulting a doctor first.

No routine lab tests (like blood counts or liver panels) are required for the standard use of Pyrethrum Extract. Monitoring should focus on:

• Visual Inspection: Checking the scalp and hair for live lice 24 hours after treatment.
• Skin Assessment: Monitoring the application site for signs of worsening redness or allergic reaction.
• Respiratory Monitoring: Especially in children with a history of allergies or asthma.

Pyrethrum Extract does not typically cause drowsiness or cognitive impairment. However, if an accidental ingestion occurs or if a patient experiences a severe allergic reaction, they should not drive and should seek emergency assistance.

There are no known direct interactions between topical Pyrethrum Extract and alcohol consumption. However, alcohol can cause vasodilation (widening of blood vessels), which might theoretically increase skin sensitivity or the sensation of itching during treatment.

There is no withdrawal syndrome associated with Pyrethrum Extract. Treatment is discontinued once the two-dose cycle is complete and the infestation is cleared. If the infestation persists after two treatments, do not continue using the product; instead, contact your healthcare provider to discuss alternative treatments like Malathion or Ivermectin.

> Important: Discuss all your medical conditions, especially allergies to flowers or plants, with your healthcare provider before starting Pyrethrum Extract.

Because Pyrethrum Extract is applied topically and has minimal systemic absorption, there are no documented 'absolute' drug-to-drug contraindications that result in systemic toxicity. However, you should not use multiple different lice treatments (e.g., using Pyrethrum and Lindane simultaneously) unless specifically directed by a doctor, as this significantly increases the risk of severe skin irritation and chemical burns.

• Other Topical Medications: Avoid applying other medicated creams, ointments, or lotions to the same area where Pyrethrum Extract is being used. Other chemicals may alter the absorption of pyrethrins or cause an unpredictable skin reaction.
• Piperonyl Butoxide Synergism: While this is a planned interaction in the bottle, be aware that any other product containing Piperonyl Butoxide (such as some flea treatments for pets) can increase the potency and toxicity of pyrethrins if they come into contact with the patient.

• Hair Dyes and Perms: Pyrethrum Extract may interact with the chemicals used in recent hair color treatments or permanent waves. It is generally recommended to wait at least 48 to 72 hours after a chemical hair treatment before applying a pediculicide to avoid hair damage or scalp irritation.
• Skin Permeability Enhancers: Products containing high concentrations of alcohol or certain surfactants applied to the skin may increase the systemic absorption of pyrethrins, potentially leading to a higher risk of side effects.

There are no known interactions between Pyrethrum Extract and food, including grapefruit, dairy, or caffeine. Since the medication is not ingested, dietary factors do not influence its metabolism or efficacy.

There are no documented interactions with herbal supplements like St. John's Wort or Ginkgo Biloba. However, patients using other botanical topical treatments (like tea tree oil or neem oil) should stop using them before applying Pyrethrum Extract to prevent cumulative skin irritation.

Pyrethrum Extract is not known to interfere with common laboratory tests, including blood glucose, urinalysis, or cholesterol panels. It does not typically cause false positives on drug screenings.

Management Strategy

1. 1Mechanism: Most interactions with Pyrethrum Extract are pharmacodynamic (additive irritant effects on the skin) rather than pharmacokinetic (interference with enzymes).
2. 2Consequence: The primary risk is 'contact dermatitis' or 'chemical irritation' which can lead to skin breakdown.
3. 3Strategy: Always clean the skin of other products before applying Pyrethrum Extract. Inform your doctor if you are using any prescription-strength skin treatments for conditions like psoriasis or eczema.

> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, even if they are 'natural' or applied to the skin.

Pyrethrum Extract must NEVER be used in the following circumstances:

• Known Hypersensitivity to Pyrethrins: If you have had a previous allergic reaction to any product containing pyrethrum or pyrethrins, do not use this medication. The reaction can become more severe with subsequent exposures.
• Chrysanthemum Allergy: Because the drug is a direct extract of the Chrysanthemum flower, an allergy to this specific plant is an absolute contraindication due to the high risk of anaphylaxis.
• Ragweed Allergy (Severe): Individuals with severe, systemic allergies to ragweed should avoid Pyrethrum Extract. The proteins in ragweed are structurally similar to those in pyrethrum, leading to 'cross-reactivity.'
• Infants under 2 months of age: The skin of very young infants is much thinner and more permeable, and their metabolic pathways are not fully developed to handle even small amounts of absorbed pyrethrins.

Conditions requiring a careful risk-benefit analysis by a physician:

• Pregnancy and Breastfeeding: While systemic absorption is low, the lack of controlled human trials means it should only be used if clearly needed.
• Asthma and Reactive Airway Disease: The risk of bronchospasm (tightening of the airways) must be weighed against the need for treatment. Alternative treatments like Ivermectin lotion may be safer for severe asthmatics.
• Broken or Infected Skin: If the scalp has deep scratches, bleeding, or signs of infection, the risk of systemic absorption increases. A doctor may need to treat the infection before treating the lice.

Patients should be aware of cross-sensitivity with the following substances:

• Pyrethroids: These are synthetic versions of pyrethrins (e.g., Permethrin). If you are allergic to Permethrin, you are likely allergic to Pyrethrum Extract.
• Asteraceae/Compositae Family: This plant family includes sunflowers, daisies, marigolds, and echinacea. Allergies to any of these plants warrant extreme caution.

> Important: Your healthcare provider will evaluate your complete medical history before prescribing or recommending Pyrethrum Extract.

Pyrethrum Extract is classified by the FDA as Pregnancy Category C (under the old system). This means that animal reproduction studies have shown an adverse effect on the fetus in some cases, but there are no adequate and well-controlled studies in humans.

• Trimester-Specific Risks: There is no evidence of specific teratogenicity (birth defects) in humans. However, during the first trimester, any chemical exposure should be minimized.
• Clinical Recommendation: Healthcare providers typically recommend Pyrethrum Extract during pregnancy only if the benefits outweigh the risks. Topical Permethrin 1% is often considered a first-line alternative with a slightly more robust safety profile in pregnancy.

It is unknown whether pyrethrins or piperonyl butoxide pass into human breast milk. However, because systemic absorption is so low, the amount reaching the milk is likely negligible.

• Precautions: If treating the body or breasts, ensure the medication is thoroughly washed off before nursing to prevent the infant from ingesting the product or inhaling vapors.
• Infant Safety: Monitor the nursing infant for any signs of skin rash or respiratory distress.

• Approved Age: Pyrethrum Extract is generally approved for children 2 years of age and older.
• Safety in Children: Children have a larger surface-area-to-body-weight ratio than adults, meaning they can absorb more of a topical drug relative to their size. Caregivers must be careful not to exceed the recommended 10-minute application time.
• Conditions Not Approved: Do not use for the treatment of lice in the eyelashes of children; this requires a specific medical intervention by a pediatrician or ophthalmologist.

• Skin Integrity: Older adults often have thinner, more fragile skin (atrophy), which may be more prone to irritation or increased absorption.
• Cognitive Concerns: Patients with dementia or significant cognitive impairment should have the medication applied by a caregiver to prevent accidental ingestion or eye contact.
• Polypharmacy: While drug interactions are few, the overall health status of the elderly patient should be considered, particularly respiratory health.

Systemic absorption of topical pyrethrins is less than 1%. Therefore, no dosage adjustments are necessary for patients with chronic kidney disease or those on dialysis. The kidneys are not significantly stressed by the topical application of this extract.

In the rare event that pyrethrins are absorbed systemically, they are metabolized by the liver. In patients with severe hepatic failure (Child-Pugh Class C), there is a theoretical risk of slower clearance of the drug, but this is not considered clinically significant for a one-time or two-time topical application.

> Important: Special populations require individualized medical assessment to ensure the safest possible treatment outcome.

Pyrethrum Extract is a neurotoxicant that targets the nervous system of ectoparasites. The active esters (pyrethrins) act on the voltage-gated sodium channels located along the axons of nerve cells.

1. 1Binding: The pyrethrin molecules bind to the sodium channels while they are in the open state.
2. 2Prolonged Conductance: This binding prevents the channels from closing (inactivating) at the normal rate.
3. 3Repetitive Discharge: This leads to a 'prolonged after-potential,' causing the nerve to fire repeatedly and uncontrollably.
4. 4Knockdown: The parasite loses motor control (the 'knockdown' effect).
5. 5Death: Eventually, the constant firing leads to metabolic exhaustion and death.

Piperonyl Butoxide is added to inhibit the microsomal enzymes (cytochrome P450) in the louse that would otherwise break down the pyrethrins, thus ensuring the parasite cannot recover.

• Onset: The 'knockdown' effect on lice is almost immediate upon contact.
• Duration: The lethal effect occurs within the 10-minute application period, provided the lice are in direct contact with the liquid.
• Tolerance: Some populations of lice have developed 'knockdown resistance' (kdr), which involves genetic mutations in their sodium channels that make them less sensitive to pyrethrins.

| Parameter | Value |

|---|---|

| Bioavailability | < 1% (Topical) |

| Protein Binding | N/A (Negligible systemic levels) |

| Half-life | 1-2 hours (if absorbed) |

| Tmax | N/A (Topical) |

| Metabolism | Hepatic via Oxidation/Hydrolysis |

| Excretion | Renal (Metabolites) |

• Molecular Components: A mixture of Pyrethrin I (C21H28O3), Pyrethrin II (C22H28O5), Cinerin I & II, and Jasmolin I & II.
• Solubility: Insoluble in water; soluble in organic solvents and oils.
• Stability: Pyrethrins are unstable in the presence of light and air (photo-labile), which is why they do not persist in the environment or on the hair for long periods.

Pyrethrum Extract is classified as a Botanical Pediculicide. It is the natural precursor to the synthetic Pyrethroid class of medications, which includes Permethrin. While they share a similar mechanism, Pyrethrum Extract is often preferred by those seeking a naturally derived option, although it typically requires a second application compared to some synthetic alternatives.