PIPERAZINES

Question 1

SUBSTANCES

Answer 1

Piperazine (phosphate, adipate, citrate) Diethylcarbamazine (citrate)

Question 2

MECHANISM OF ACTION

Answer 2

• Block neuromuscular transmission (GABA agonistic effect) in the parasite by hyperpolarizing the nerve membrane, which leads to flaccid paralysis, (reversible vermifugal effect, without killing them!)
• Also block succinate production by the worm.
• The parasites, paralyzed and depleted of energy, are expelled by peristalsis.

Question 3

ANTHELMINTIC SPECTRUM

Answer 3

• The spectrum of activity of Piperazine is largely against ascarid parasites in all animal species. Large doses against hookworms.
• Diethylcarbamazine heartworm prevention in dogs. Has also been used to treat prepatent Dictyocaulus viviparus infections (lungworm infection) in cattle, (relatively ineffective against the adult worms).

Question 4

PHARMACOKINETIC FEATURES

Answer 4

• Piperazine is rapidly absorbed from the GI tract,
• Excretion via kidneys. Piperazine base can be detected in the urine as early as 30 min. after administration. (Residues in eggs.)
• The excretion rate is maximal at 1-8 h, and excretion is practically complete within 24 h.

Question 5

SIDE-EFFECTS

Answer 5

• The safety margin is limited (less in horses, puppies and kittens).
• TI 3-10
• Toxic signs caused by large doses including vomiting, diarrhoea and ataxia.

Question 6

APPLICATION

Answer 6

Piperazine PO
Dogs, Cats, Pigeon 120 (240 hookworm) mg/kg B.W.

Diethylcarbamazine IM/PO
Cattle, IM 22 mg/kg B.W. for 3 consecutive days, or 44 mg/kg once.
Dog, PO 5-10 mg/kg B.W. daily throughout the mosquito season.