What Is Ovide Used for?: A Prescription Medication for Lice

October 6, 2025 •

3 min read

According to the CDC, head lice infestation (pediculosis capitis) is the most common parasitic infection among people in the United States and Europe. In cases where other treatments are ineffective, a prescription medication is sometimes needed. Ovide, containing the active ingredient malathion, is a powerful lotion specifically used for these persistent cases of head lice infestation.

Quick Summary

Ovide (malathion) lotion is a prescription topical anti-parasite medication used to treat head lice and their eggs. It works by inhibiting the nervous system of lice, and is often used when lice have developed resistance to other treatments. Use is indicated for patients six years of age and older.

Key Points

Treats Head Lice and Nits: Ovide lotion is a prescription topical treatment specifically indicated for infestations of head lice and their eggs.
Contains Malathion: The active ingredient, malathion, is a powerful organophosphate that kills live lice and some nits by inhibiting their nervous system.
Effective Against Resistant Lice: Ovide is often used when lice have developed resistance to common over-the-counter treatments.
Prescription Only and Age Restricted: Unlike many other products, Ovide is available by prescription only and is approved for individuals 6 years of age and older.
Proper Application is Crucial: The lotion is applied to dry hair and left on for the prescribed duration, followed by shampooing and nit removal.
Flammable Warning: Ovide is highly flammable and must be kept away from all heat sources and open flames during and after application, until hair is completely dry.
Requires Physician Supervision: Due to its potency and safety precautions, Ovide should only be used under the direct supervision and guidance of a healthcare professional.

What is Ovide (Malathion) Lotion?

Ovide is the brand name for malathion, a topical lotion formulated to eradicate head lice and their eggs (nits). As a potent pediculicide, Ovide is typically reserved for cases where over-the-counter treatments have failed due to emerging resistance in some lice populations. Its active ingredient, malathion, is an organophosphate insecticide that has been used for various pest control purposes, including agricultural uses and mosquito control. For medical use, it is prepared in a pharmaceutical-grade, 0.5% lotion with specific ingredients to enhance its efficacy on scalp hair.

How Ovide Kills Lice and Nits

Ovide's powerful action comes from its ability to inhibit cholinesterase, an enzyme essential for the proper functioning of the lice's nervous system. By blocking this enzyme, malathion causes a rapid, massive paralysis in the insects, leading to their death. This mechanism is particularly effective against lice that have developed resistance to pyrethrins and permethrin, the active ingredients in many common over-the-counter lice products.

Additionally, Ovide demonstrates ovicidal activity, meaning it kills some of the lice eggs. This occurs because the compound interferes with the development and eventual hatching of the nymphs. The formulation also contains isopropyl alcohol, which helps to dehydrate the eggs. These combined effects contribute to its efficacy, although the need for retreatment should be discussed with a healthcare provider if live lice persist after an appropriate waiting period.

Proper Application and Safety Precautions

Proper use of Ovide is crucial for both effectiveness and safety, and should only be done under a doctor's supervision.

Here are some general steps for application:

Step 1: Apply Ovide lotion to dry hair and scalp as directed by a healthcare professional. Ensure thorough coverage, particularly in areas where lice are commonly found.
Step 2: Allow the hair to dry naturally and remain uncovered. It is critical to avoid any open flames, cigarettes, or electric heat sources, such as hair dryers, curling irons, or space heaters, as the lotion is flammable.
Step 3: Leave the lotion on the hair for the duration recommended by your doctor, typically several hours.
Step 4: After the recommended time has passed, shampoo and rinse the hair thoroughly. Use a fine-toothed nit comb to remove dead lice and eggs as instructed.

Safety warnings include:

Ovide should not be used on children younger than 6 years of age.
Keep Ovide out of reach of children and avoid contact with eyes, nose, or mouth.
Wash hands immediately after applying the lotion.
If skin irritation is severe, consult a physician.

Ovide vs. Other Common Head Lice Treatments


Feature	Ovide (Malathion)	Permethrin (e.g., Nix)	Spinosad (e.g., Natroba)
Availability	Prescription only	Over-the-counter	Prescription only
Age Restriction	6 years and older	2 months and older	6 months and older
Primary Action	Paralyzes and kills lice and eggs by inhibiting cholinesterase	Kills live lice but is less effective against nits; retreatment is often needed	Kills lice and nits with one application; non-pesticide
Ovicidal Activity	Partially ovicidal	Less effective ovicidal action	Highly ovicidal
Flammability	Highly flammable	Not flammable	Not flammable
Risk of Resistance	Effective against some resistant strains of lice	Widespread resistance reported in some areas	Less common, as it is a non-pesticide
Dwell Time	Varies by prescription, typically several hours	10 minutes	10 minutes

Potential Side Effects

Common side effects associated with Ovide lotion include scalp irritation, stinging, burning, or a temporary increase in dandruff. Less common but more severe reactions can include chemical burns or signs of a systemic reaction, such as skin blistering. If these occur, discontinue use and consult a healthcare provider. Accidental contact with the eyes can cause mild conjunctivitis.

Conclusion

Ovide is a powerful prescription-only treatment for head lice, particularly valuable for infestations resistant to more common over-the-counter products. Its active ingredient, malathion, functions by disrupting the nervous system of lice and is also partially ovicidal, killing some of the eggs. Proper application and adherence to safety precautions, especially regarding flammability, are essential. While it offers a strong solution for persistent lice problems, it is important to follow a doctor's guidance and be aware of potential side effects and safety considerations.

For more information on lice and other ectoparasitic infections, consult the official guidelines from the Centers for Disease Control and Prevention.

Frequently Asked Questions

The active ingredient in Ovide is malathion, an organophosphate insecticide that works by disrupting the nervous system of head lice.

No, Ovide (malathion) is a prescription-strength topical lotion and is not available over-the-counter.

Ovide is typically approved for use in individuals 6 years of age and older. Its use in children younger than 6 is not recommended.

The duration Ovide lotion should be left on the hair is determined by the prescribing healthcare provider, typically for several hours.

No, Ovide is flammable. You should not use any electric heat sources, such as hair dryers, or expose your hair to open flames while the hair is wet with the lotion.

Mild stinging or scalp irritation is a common side effect. However, if irritation is severe or persists, you should wash the area immediately and consult a physician.

If live lice are still visible after the recommended waiting period, a second application of Ovide may be necessary. Always consult your doctor for retreatment instructions.

While primarily indicated for head lice, Ovide is sometimes used off-label to treat pubic lice. It is not generally used for body lice, and any off-label use should be determined by a healthcare provider.