Depolarizing neuromuscular

The answer is c. (Hardman, p 1022.) Pyrantel pamoate is an antihelminthic that acts primarily as a depolarizing neuromuscular blocker. In certain worms, a spastic neuromuscular paralysis occurs, resulting in the expulsion of the worms from the intestinal tract of the host. Pyrantel also exerts its effect against parasites via release of acetylcholine and inhibition of cholinesterase. 

Pyrantel is a dmg of first choice for the treatment of a number of round-, thread- and hookworm infestations. However, it has no activity against whipworm. Its mechanism of action is based on triggering the release of acetylcholine in helminths causing a depolarizing neuromuscular blockade that leads to spastic paralysis. 

E. Succinylcholine is the only depolarizing neuromuscular blocking in widespread clinical use, particularly as an aid for intubation. Its administration may produce muscle fasciculation and postoperative muscle pain. It can produce hyperkalemia in patients with muscle damage or prolonged paralysis in patients with atypical plasma cholinesterase. 

Metrifonate is an organophosphorous compound that is effective only in the treatment of S. haematobium The active metabolite, dichlorvos, inactivates acetylcholinesterase and potentiates inhibitory cholinergic effects. The schistosomes are swept away from the bladder to the lungs and are trapped. Therapeutic doses produce no untoward side effects except for mild cholinergic symptoms. It is contraindicated in pregnancy, previous insecticide exposure, or with depolarizing neuromuscular blockers. Metrifonate is not available in the United States. 

Mechanism of Action A depolarizing neuromuscular blocking agent that causes the release of acetylcholine and inhibits cholinesterase. Therapeutic Effect Results in a spastic paralysis of the worm and consequent expulsion from the host s intestinal tract. 

The characteristics of a depolarizing neuromuscular blockade are summarized in Table 27-2 and Figure 27-7. 

Both pyrantel (13a) and morantel (13b) are depolarizing neuromuscular blocking agents that stimulate ganglia and also possess acetylcholine-like actions on smooth muscle. 

Mechanism of action of depolarizing neuromuscular blocking drugs. 

Pyrantel pamoate [pi RAN tel] along with mebendazole is effective in the treatment of infections caused by roundworms, pinworms (see Figure 36.4), and hookworms. Pyrantel pamoate is poorly absorbed orally and exerts its effects in the intestinal tract. It acts as a depolarizing neuromuscular blocking agent, causing persistent... 

A variety of other tropane alkaloids have been isolated of which the most important is anatoxin-A, a highly toxic nACh-R agonist and depolarizing neuromuscular blocking agent deriving from Anabaena cyanobacterium species that can contaminate inland waters. 

Driessen JJ, Vree TB, van Egmond J, Booij LH, Crul JF. Interaction of midazolam with two non-depolarizing neuromuscular blocking drugs in the rat in vivo sciatic nerve-tibialis anterior muscle preparation. Br J Anaesth 1985 57(ll) 1089-94. 

Nicotinic symptoms may be observed initially, but muscarinic signs can be observed concurrently. Later in the course of poisoning, muscarinic signs predominate. Persistent depolarizing neuromuscular blockade may develop after initial resolution of the cholinergic crisis and can cause sudden respiratory failure and death (Reutter, 1999 Weinstein Alibek, 2003). Initial patient diagnoses and treatments are likely to be based on observations of signs and symptoms by the paramedic or other health care professionals at the scene (Table 25.3). Rescuers and health care workers must prevent direct... 

Hughes R, Chappie DJ. Effects on non-depolarizing neuromuscular blocking agents on peripheral autonomic mechanisms in cats. Br J Anaesth 1976 48(2) 59-68. 

Burns are associated with resistance to atracurium (43), as for several other non-depolarizing neuromuscular blocking agents. The EC50 is increased and dose requirements may be increased by up to 2-3 times. The resistance varies with the burn area and the time from injury (SEDA-12, 116), being maximal at 15 0 days in patients repeatedly anesthetized. 

In contrast to reports on other non-depolarizing neuromuscular blocking agents, resistance to atracurium has not been found in patients taking long-term carbamazepine (SEDA-13, 104) (58). 

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