Belladonna

Name: Belladonna

What is the most important information I should know about belladonna?

Use caution when driving, operating machinery, or performing other hazardous activities. Belladonna may cause dizziness, drowsiness, or blurred vision. If you experience dizziness, drowsiness, or blurred vision, avoid these activities.

Use alcohol cautiously. Alcohol may increase drowsiness and dizziness while you are taking belladonna.

Avoid becoming overheated in hot weather. Belladonna increases the risk of heat stroke because it causes decreased sweating.

How should I take belladonna?

Take belladonna exactly as directed by your doctor. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you.

Take each dose with a full glass of water.

To ensure that you get a correct dose, measure the liquid form of belladonna with a special dose-measuring spoon or cup, not with a regular tablespoon. If you do not have a dose-measuring device, ask your pharmacist where you can get one.

Store belladonna at room temperature away from moisture and heat.

Belladonna Pharmacokinetics

Absorption

Bioavailability

Well absorbed from the GI tract; however, animal studies have shown differences in the absorption rates of l-hyoscyamine and galenical preparations of belladonna.a

Distribution

Extent

Not known whether belladonna is distributed into milk.b d g h i

Atropine, hyoscyamine, and scopolamine cross the placenta.c

Atropine and hyoscyamine readily cross the blood-brain barrier.c

Elimination

Metabolism

Hydrolyzed to tropine and tropic acid.a

Elimination Route

Excreted in urine and, apparently to a lesser extent, in feces.a

Stability

Storage

Oral

Belladonna Leaf

Tight, light-resistant containers.a

Belladonna Extract

Tight containers at ≤30°C.a

Belladonna Tincture

Tight, light-resistant containers at <40°C (maintain between 15–30°C).a Protect from direct sunlight and excessive heat.a

Belladonna Alkaloids with Phenobarbital Elixir and Immediate- and Extended-release Tablets

Well-closed, light-resistant containers at 20–25°C.b h i Protect from light and moisture.b h i

Rectal

Suppositories

15–30°C.g Do not refrigerate.g

Actions

  • Belladonna is a term applied to the various galenical preparations of the naturally occurring solanaceous alkaloids.a Antimuscarinic activity results principally from the atropine (dl-hyoscyamine) content.a g

  • Competitively inhibits acetylcholine or other cholinergic stimuli at autonomic effectors innervated by postganglionic cholinergic nerves and, to a lesser extent, on smooth muscles that lack cholinergic innervation.c At usual doses, principally antagonizes cholinergic stimuli at muscarinic receptors and has little or no effect on cholinergic stimuli at nicotinic receptors.c

  • Antimuscarinics also have been referred to as anticholinergics (cholinergic blocking agents), but this term is appropriate only when it describes the antagonism of cholinergic stimuli at any cholinergic receptor, whether muscarinic or nicotinic.c

  • Also have been referred to as parasympatholytics because the antagonized functions principally are under the parasympathetic division of the nervous system.c

  • Receptors at various sites are not equally sensitive to inhibition of muscarinic effects.c Relative sensitivity of physiologic functions (proceeding from the most sensitive) is as follows: secretions of the salivary, bronchial, and sweat glands; pupillary dilation, ocular accommodation, and heart rate; contraction of the detrusor muscle of the bladder and smooth muscle of the GI tract; and gastric secretion and motility.c Doses used to decrease gastric secretions are likely to cause dryness of the mouth (xerostomia) and interfere with visual accommodation, and possibly cause difficulty in urinating.c

  • Various antisecretory effects in the GI tract, including reduction of salivation (producing xerostomia) and gastric secretions (only partial reduction in gastric acid secretion).c Prolonged inhibitory effects on the motility of the esophagus, stomach, duodenum, jejunum, ileum, and colon.c

  • Relaxes lower esophageal sphincter with a resultant decrease in lower esophageal sphincter pressure.c

  • Decreases the tone and amplitude of contractions of the ureters and bladder.c May cause urinary retention (e.g., in patients with urinary obstruction).c

  • Can reverse reflex vagal cardiac slowing or asystole such as that induced by inhalation of irritant vapors or by vagal stimulation (e.g., carotid sinus stimulation, pressure on the eyeball).c

  • May cause cutaneous vasodilation, especially at toxic doses (atropine flush).c

  • Reduces secretions from the nose, mouth, pharynx, and bronchi.c Relaxes smooth muscles of the bronchi and bronchioles with a resultant decrease in airway resistance.c

  • Stimulates the medulla and higher cerebral centers and exhibits CNS effects similar to those produced by antimuscarinics used in the treatment of parkinsonian syndrome (e.g., trihexyphenidyl).c

  • Blocks the responses of the sphincter muscle of the iris and the ciliary muscle of the lens to cholinergic stimulation, producing mydriasis and cycloplegia and a resultant decrease in ocular accommodation.c Little effect on IOP except with angle-closure glaucoma where IOP may increase.c

  • Reduces the volume of perspiration by inhibiting sweat-gland secretions.c May suppress sweating sufficiently to increase body temperature.c

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