Anticholinergic drugs Definition: Are drugs that block cholinergic receptors. They oppose their parasympathetic actions to produce actions similar to the sympathetic system’s. Classification PV eee to} Ganglionic Mechanism of action of blockers Antimuscarinic drugs: used to treat muscular i blockers reversible competitive blockade of hypertension, ini . but not any e.g. muscle muscarinic receptors. not +e. muscle Suffix ine: More specific less side effects Atropine eo Lipid soluble feel pic a = — Benztropine and tertiary Good oral Taonesnal oo amines absorption Hyoscine Homatropine Good distribution Cross BBB >have CNS actions Tropicamaide Pirenzepine Atropine& hyoscine can block all muscarinic receptors (non selective), Thus have many ADRs Ipratropium Glycopyrrolate Sensitivity: NT 1. Salivary, bronchial, & sweat glands (the most) Oxybutynin 2. Smooth muscle & heart 3. Gastric glands & Smooth muscle(ered se tom eee) let leme leery Pete) etter la tlie rye Ce Tau Bae lo ae There will be 2 Contraction: 1. Circular muscle of iris > 1. Circular muscle of iris > relaxation(mydriasis) Contraction(miosis) circular 2. Ciliary muscles > 2. Ciliary muscles > relaxation (cycloplegia) Contraction Result in: Result in: + Accommodation for near | * loss of accommodation for near vision, vision Loss of light reflex. + Reduce intraocular pressure | + Increase I.0.P , thus contraindicated in glaucoma. + Tachycardia (increase in heart rate) cvs Bradycardia (decreased H.R.) | + 1 Conduction speed in the AV node of the heart (+ve dromotropic effect) LUTTETS a Contraction of smooth muscles | Relaxation of smooth muscles of urinary bladder. NeTaall Relaxation of sphincter contraction of sphincter Urination Urinary retention Decrease all secretions: {Salivary secretion -> Dry mouth. , Increase of : erat i i i sali pee ee aerial + Sweating — dry skin > Fever and hyperthermia bo bronchial, in infants and children. intestinal secretions . . + Bronchial secretion -> T Viscosity {Lacrimal secretion —> Sandy eye, dry eye Increase peristalsis Decrease peristalsis (¥ GIT motility — Antispasmodic effect) Increase secretion Decrease secretion Contraction of smooth muscles | Relaxation of smooth muscles Relaxation of sphincter Contraction of sphincter Diarrhea constipation 5 1. Bronchoconstriction 1. Relaxation of bronchial muscles MAARAIMRAL 2. Increase bronchial secretion (Bronchodilatation) Bau) 2. Decrease bronchial secretion (T viscosity)Anti-muscarinic drugs: natural alkaloids ATROPINE VS HYOSCINE Atropine (era Cit} Long duration (t,,)_ 4h) Hyoscine (scopolamine) Shorter duration than Atropine More CVS effect Therapeutic dose: 1. J Vasodilation induced by cholinomimetics 2. Cutaneous vasodilation in children by releasing prostaglandins (atropine flush). 3. initial bradycardia followed by tachycardia Toxic dose: atropine flush in adults. Less CVS effect POTENTIAL RELEVANCE: Hyoscine may represent an alternative to atropine as a PRE-ANESTHETIC MEDICATION for preventing bradycardia during operations Less CNS effect CNS depression (Sedation). Antiemetic effect (block vomiting center) Antiparkinsonian effect (block basal ganglia). Toxic dose: Hyperthermia - excitement- hallucination followed by respiratory depression and coma More CNS effect better sedation Better antiemetic action (only Hyoscine is used for motion sickness) * (anti- vomiting) Can produce Amnesia (loss of recent memory) Used as pre- anesthetic Scopolamine or hyoscine is preferable than atropine as antiemetic because it has more effect on CNS. It is also preferable as pre-anesthetic medication as it has amnesic and more sedative action than atropine. Amnesia: a deficit in memory caused by brain damage muscles? Q: Can antimuscarinic drugs reverse the action of neostigmine on skeletal A: No, Because skeletal muscles only have Nicotinic receptors. You Video : Anticholinergic AgentsAnti-muscarinic drugs side effects Side effects of anti-muscarinic drugs, specifically atropine : Remember: effects of a drug other than the desired ones, are regarded as “side effects” are Bowel SOUNDS Anticholinergic x Ay til t® — e ae OT Peel mame hy Bet SUM Pamela clog STATS asc C Brea ote) 5. On the GIT err TiC 6. Secretions Bega) UCR Ly pe etc) re ee care) ee ee any Cue) (increased body temperature) Sel: (dilation of cutaneous blood vessels > ) Anti-muscarinic drugs toxicit Treatment: 1) Gastric lavage. (Washing out the stomach with water or medications) 2) Anticonvulsant. For seizures Drug toxicity is caused by overdose or chronic use ATROPINE OVERDOSE. 3) Cooling blanket. For hyperthermia 4) antidote: 3S em (anti-cholinesterase = reversible c cholinesterase inhibitor) = Mages alee It is given LV slowly Physostigmine is lipid soluble > crosses BBB > blocks the effect of atropine centrallyAntimuscarinic + Pre-anesthetic medication + Antispasmodic " = 1) Atropine . . g * Traveler's diarrhea with opioid (Atropine + a diphenoxylate) § CNS + Pre-anesthetic medication & Hyoscine + Antispasmodic * Motion sickness (anti-vorniting) Benztropine Parkinson's disease — specific on CNS (more lipid soluble) Ben son park) Homatropine Fundus examination of eye Eye Tropicamide + Asthma &COPD Respiratory pulm System Given by inhalation Ipratropium Synthetic atropine substitutes Pirenzepine Stomach Peptic ulcer (blocks M1 at the parietal cells) GlycopyrrolaTe GIT Antispasmodics in intestinal hypermotility OxybUTynin ut + Urinary urgency UT * — Urinary incontinence Try Cortese niscie)} (secondary to thyrotoxicosis ees or cardiac insufficiency) ee Set pressure 4) Prostate hypertrophy Ey Kettles) fest Pesce eee ne Bren aurctis Ceesmuscarinic drugs O oO (trophy 4) (Ipratropium) — OC aipper dt cai - (Pirenzepine) + Oxy the beauty (Oxybutynin) * Wanted atrophy (Atropine) —_ benzene (Benziropine) Made a big scene (IIyoscine) And that made the Ox happy. (4-4) + The trophy camed (Tropicamaide) + Itis at home (Homatropine) ho So he told him to go copy Rolate (Glycopyrrolate) and study for once. And once he did..!! + A short story to remember the names of the drugs: Oxy the buty (Oxybutynin) wanted a trophy (Atropine) so he went to benzene (Benztropine)and told him (Trophy 4!) (Ipratropium)but he was too busy looking for his zipper and said (4:5!) Ge) (Pirenzepine) he made a big scene (Hyoscine), he got angry and tolled him why don’t you go copy Rolate (Glycopyrrolate) and study for once if you really want it that bad. when he did, he told him (the tropi camaide) (Tropicamaide) its at home (Homatropine), and that made him happy.Drugs on the Autonomic nervous system Act on the Sympathetic - System (SNS) | N, y \ nN - * : Adrenergic: Dopamine’s Muscarinic Nicotinic a1, @,B;,B2 receptors (Mi-s) (Nn Nin) Gives Sympathetic effects ~ Antinicotonic Inhibit the eff skeletal muscle via the nicotinic muscle receptor (Nin) Inhibit the nicotinic neuronal receptor (Nj) of both parasympathetic and sympathetic ganglia + Lipid soluble. a | + Good oral absoretion. + Good distribution. jt Cross 88. i SR CT Naturally ‘occurring sinaioias (e.g. Atropine, Hyoscine) + Intestinal spasm as antispasmodics. *_ Pre-anesthetic medication. Therapeutic dose: , vasodilation | Can produce amnesia, —_ Toni dose atropine fish : + RS: Bronchodilator. : ic PAC UP & VIP ps "+! + Parkinson. U atropine effects: Same, but ite asthma. + CNS: (Sedation, Antiemetic, | + Short duration of action. eae Antiparkinsonian). + Less CVS effects. :{ * Urinary urgency. Toxic dose: Hallucination excitation, | + More CNS depressant. || + Peptic ulcer. hyperthermia, (iall'salways sxcted & per). * More antiemetic(Used in: * Vomiting. * CVS: Tachycardia, 7 AV conduction. motion sickness) | q + Constipation. Children in case of atropine. "Ani ! TIOP, sandy eye. 1c ' + Secretion: Dry mouth, fever, * viscosity, I Treatment of tovictye 1 * Glaucoma (angle closure glaucoma) | | sandy eye) | astrclavage || Tachycardia ' ‘+ GIT: Constipation, paralyticileus. + Anticonvulsant, | + Prostate hypertrophy in old patients. | | + UT:Urinary retention. | + Cooling blanket. ' 'PTT ra meu Ue cs Cholinergic Antagonist drugs — Anti-muscarinic + Reversible competitive blockade of muscarinic receptors. Wie TN) atropineg hyoscine can block all muscarinic receptors (not selective). Naturally occurring alkaloids Dyn Pet id Lipid soluble, good oral absorption & distribution, cross BBB. Duration Long Short metic, CNS depressant action. in (block basal ganglia). antiemetic action CNS Toxic dose: Hallucination, excitation, Can produce amnesia. + Passive mydriasis > (due to paralysis of circular muscle) Eye — | + ¥eloplegia (loss of near accommodation) > (due to paralysis of ciliary muscle) t reflex, 1 1.0.P (glaucoma), W Lacrimal secretion -> lead to sandy eye. hyperthermia. (Hall is always excited & hyper) Pre-anesthetic medication, 8 Pre-anesthetic medication Antispasmodic. ‘Motion sickness, antispasmodic. 5 Tachycardia, 7? AV conduction. = , 3] CVS | Therapeutic dose: vasodilation. Cvs effect 2 Toxic dose: atropine flush, {RS _| Relaxation of bronchial muscles (bronchodilator), J Bronchial secretion > 1 viscosity 3 c -—< a Secretions Dry mouth, dry skin leading to fever, increased Viscosity, Sandy eye + Relaxation of smooth muscles, 4 contraction of sphincter leading to Constipation. GIT _| + J crt motility > antispasmodic effect, may cause paralytic ileus, UT Relaxation of smooth muscles, Sphincter contraction -> Urinary retention. + Tachycardia, Glaucoma (angle closure glaucoma), Prostate hypertrophy in old patients, OGG) — Constipation, Children (in case of atropine). Synthetic atropine substitutes CU aC ae ce CeO SL] * Asthma Parkinson's . + COPD — | Antispasmodies | UR2TY 4d Fundus examination of eye | Peptic ulcer nm ntyvcrmotitty | ufgency & isease (by YP Y | incontinence inhalation)