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Generic Name: Pyrvinium

Primary: AP200{03}

Commonly used brand name(s): Vanquin.

Another commonly used name is
viprynium .
Note: For a listing of dosage forms and brand names by country availability, see Dosage Forms section(s).

*Not commercially available in the U.S.


Anthelmintic (oral-local)—


Note: Because pyrvinium is not commercially available in the U.S., the use of brackets in this monograph reflects the lack of labeled (approved) indications for this medication.


[Enterobiasis (treatment)]—Pyrvinium is used in the treatment of enterobiasis caused by Enterobius vermicularis (pinworm). {07} However, pyrvinium has generally been replaced by other anthelmintics (e.g., mebendazole or pyrantel).


Physicochemical characteristics:
Molecular weight—

Mechanism of action/Effect:

Appears to prevent the parasite from utilizing exogenous carbohydrates.


Not appreciably absorbed from gastrointestinal tract. {01} {05}

    Fecal (unchanged).

Precautions to Consider


Studies in humans have not been done. Problems in humans have not been documented. Since pyrvinium is not absorbed, it is the preferred medication for the treatment of pinworm infections in pregnant women. {06}

Studies in animals have not been done.


It is not known whether pyrvinium is excreted in breast milk.{07} However, problems in humans have not been documented.


Gastrointestinal upset occurs more frequently in older children who have received large doses. {01} {05}

Because of limited experience, caution is recommended in the treatment of children weighing less than 10 kg.{07}


No information is available on the relationship of age to the effects of pyrvinium in geriatric patients.

Medical considerations/Contraindications
The medical considerations/contraindications included have been selected on the basis of their potential clinical significance (reasons given in parentheses where appropriate)— not necessarily inclusive (» = major clinical significance).

Risk-benefit should be considered when the following medical problems exist
Hypersensitivity to pyrvinium

Patient monitoring
The following may be especially important in patient monitoring (other tests may be warranted in some patients, depending on condition; » = major clinical significance):

» Perianal examinations    (cellophane tape swabs of the perianal area to detect the presence of ova may be required prior to and starting 1 week following treatment with pyrvinium, especially in patients with persisting symptoms; swabs should be taken every morning, for at least 3 days, prior to defecation and bathing, to determine efficacy or provide proof of cure; perianal examinations may also be required to ascertain the absence of adult worms in the perianal area; no patient should be considered cured unless perianal swabs have been negative for 7 consecutive days)


Side/Adverse Effects
The following side/adverse effects have been selected on the basis of their potential clinical significance (possible signs and symptoms in parentheses where appropriate)—not necessarily inclusive:

Those indicating need for medical attention
Incidence rare {04} {05}
Hypersensitivity (skin rash)

Those indicating need for medical attention only if they continue or are bothersome
Incidence rare {04} {05}
Gastrointestinal disturbances (diarrhea; nausea and vomiting; stomach cramps)
photosensitivity (increased sensitivity of skin to sunlight)

Those not indicating need for medical attention {04}
Bright red discoloration of stools and vomit

Patient Consultation
As an aid to patient consultation, refer to Advice for the Patient, Pyrvinium (Oral)

In providing consultation, consider emphasizing the following selected information (» = major clinical significance):

Before using this medication
»   Conditions affecting use, especially:
Hypersensitivity to pyrvinium

Proper use of this medication
No special preparations (e.g., dietary restrictions or fasting, concurrent medications, purging, or cleansing enemas) required before, during, or immediately after therapy

Proper administration technique

Treating all household members concurrently; treating again in 2 to 3 weeks

» Compliance with therapy; second course may be required

» Proper dosing

» Proper storage

Precautions while using this medication
Checking with physician if no improvement within a few days

» Possible skin photosensitivity; avoiding unprotected exposure to sun; using protective clothing; using a sun block product that includes protection against both UVA-caused photosensitivity reactions and UVB-caused sunburn reaction; avoiding use of sunlamp, tanning bed, or tanning booth

Washing (not shaking) all bedding and nightclothes after treatment to prevent reinfection; other measures may be recommended by some physicians

Side/adverse effects
For 24 to 48 hours or longer, produces bright red stools, which may stain clothing

Signs of side effects, especially hypersensitivity

General Dosing Information
No special preparations (e.g., dietary restrictions or fasting, concurrent medications, purging, or cleansing enemas) are required before, during, or immediately after treatment with pyrvinium.

Because of the high probability of transfer of pinworms, it is usually recommended that all members of the household be treated concurrently. {05} Retreatment is recommended 2 to 3 weeks following initial treatment.

Gastrointestinal upset occurs more frequently in older children and adults who have received large doses. {05}{07}

Oral Dosage Forms

Note: The dosing and strengths of the dosage forms are expressed in terms of pyrvinium base (not the pamoate salt).


Usual adult and adolescent dose
Enterobiasis (treatment)
Oral, 5 mg (base) per kg of body weight as a single dose. {04}{11} Repeat in two to three weeks if necessary.{07}{11}

Usual adult prescribing limits
Enterobiasis—Up to a maximum of 350 mg (base) in a single dose{11}, regardless of body weight.

Usual pediatric dose
See Usual adult and adolescent dose ; {04}{11} or

Oral, 150 mg (base) per square meter of body surface as a single dose, repeated in two or three weeks.{09}

Note: Caution is recommended in children weighing less than 10 kg.

Strength(s) usually available
Not commercially available.


10 mg per mL (Rx) [Vanquin (alcohol-, gluten-, lactose-, paraben-, sulfite-, and tartrazine-free){07}]{04}

Packaging and storage:
Store below 40 °C (104 °F), preferably between 15 and 30 °C (59 and 86 °F), unless otherwise specified by manufacturer. Store in a tight, light-resistant container. Protect from freezing.

Auxiliary labeling:
   • Avoid too much sun or use of sunlamp.
   • May discolor stools.
   • Shake well.

Note: Attach label supplied by manufacturer to bottle.
When dispensing, include a calibrated liquid-measuring device.
Make sure that dose for each member of family is clearly understood.

Revised: 03/17/2000

  1. Povan package insert, PD, PDR 1986, p 1384.
  1. F&C D-List, 1986.
  1. USP DI 1989, VA Medication Classification System, p 2472.
  1. CPS 1988, Vanquin (PD), p 979.
  1. Package insert, Povan (PD), Rev 9/80, Rec 4/85.
  1. Panel comment, 2/91.
  1. Product Information: Vanquin, pyrvinium pamoate. Warner-Lambert Consumer Healthcare, Scarborough, Canada. PI reviewed 2/2000.
  1. Brown HW, Neva FA. Basic clinical parasitology. 5th ed. Norwalk: Appleton-Century-Crofts; 1983. p. 105-42.
  1. Shirkey HC, editor. Pediatric therapy. 5th ed. Saint Louis: The C.V. Mosby Company; 1975. p. 1200-1.
  1. Panelist comments, 2000 revision.
  1. Manufacturer comments, (Warner-Lambert Consumer Healthcare—Canada), 2000 revision.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.