Ganglionic Stimulants

GANGLIONIC STIMULANTS

Selective nicotinic  Nonselective/muscarinic

agonists                agonists

Nicotine (small dose)      Acetylcholine

Lobeline                Carbachol

Dimethyl phenyl   Pilocarpine

piperazinium (DMPP)    Anticholinesterases

iodide                    MCN 343A

Tetramethyl ammonium

(TMA)

Nicotine (from Nicotiana tabacum) is important in the context of smoking or chewing tobacco, but there is no clinical application of ganglionic stimulants, because no useful purpose can be served by stimulating both sympathetic and parasympathetic ganglia concurrently.

Nicotine transdermal has recently become available for treatment of nicotine dependence and as an aid to smoking cessation. It ameliorates the symptoms of nicotine withdrawal, but does not completely suppress craving, because the peak nicotine blood levels that occur after smoking are not reproduced by the patch.

NICOTINELLTTS 10, 20, 30 cm2 patches releasing 7, 14, 21 mg nicotine per 24 hr respectively.

In those smoking >20 cigarettes every day—start with 30 cm2 patch, shift to smaller patches every 5–8 days, treat for 3–4 weeks (max. 12 weeks). Headache, insomnia, flu like symptoms, dyspepsia, loose motion and local irritation are the side effects. Cardiac arrhythmias and ischaemic heart disease are the contraindications.

Varenicline This N_N subtype nicotinic receptor partial agonist is under clinical development for smoking cessation. Controlled trials have found it to reduce craving as well as nicotine withdrawal symptoms in those who stop smoking. Abstinence rates after one year were higher than placebo and comparable to bupropion (see No. 33).

Rimonabant A selective cannabinoid receptor1 (CB1) antagonist which is being tried as antismoking and anti-obesity drug. It appears to have the potential to help smoking cessation as well as maintain smoking abstinence.