A.6

Question 1

Drugs acting on GI and GU smooth muscles. Drugs influencing uterine function. Histamine and antihistamines (H1-blockers)

Answer 1

1. Smooth muscle relaxation: Papaveine, Drotaverine, Butylscopolamine, Solifenacin, Oxybutynin.
2. Tocolytic drugs - agents relaxing pregnant uterus: Atosiban, Terbutaline, Mg2+, Ethanol.
3. Agents contracting the pregnant uterus: Oxytocin, Ergotamine, Misoprostol.
4. Agents acting on male reproductive system:
   Tamsulosin
5. Histamine
6. Antihistamines: 1st generation: Diphenyhydramine, Dimetindene, Chloropyramine.
7. Antihistamines: 2nd generation: (Levo)cetrizine, (Des)loratadine, Fexofenadin.

Question 2

Papaveine, Drotaverine

Answer 2

MOA: Ca2+-channel blocker, non-selective PDE inhibitor;
ROA: p.o, parentral;
Effect: SM relaxation;
IND: GI and GU spasms;
SEs: Hypotension, arrhythmias, hepatotoxicity;
Extra: Drotaverine used to enhance cervical dilation during childbirth

Question 3

Butylscopolamine

Answer 3

MOA: Non-selective M-antagonist;
ROA: i.v or i.m;
Effect: SMC relaxation;
IND: Pain+discomfort caused by abdominal cramps or urinary tract spasms;
Extra: No CNS effect compared to scopolamine

Question 4

Solifenacin, Oxybutynin

Answer 4

MOA: M3-antagonist (Gq→Contraction);
ROA: p.o, t.d patch;
Effect: Relax the muscle in the wall of the bladder (solifenacin), decrease detrusor muscle spasms+short acting (6h) (oxybutynin);
IND: Urinary incontinence, bladder spasm (post-operative, neurogenic)

Question 5

Atosiban

Answer 5

MOA: oxytocin receptor antagonist;
ROA: i.v. ;
Effect: block the oxytocin pathway →relaxation;
IND: Prevent preterm labor; SEs: increased rate of infant death

Question 6

Terbutaline

Answer 6

MOA: short-acting β2-agonist (SABA);
ROA: aerosol inhalation, p.o, parentral;
Effect:Gs →cAMP↑→SM relaxation→uterus relaxation+brnchodilation;
IND: prevent preterm labor via uterus relaxation (from 16th week), Asthma, COPD;
SEs: Arrhythmias (may affect both mother&fetus)

Question 7

Mg2+

Answer 7

MOA: Ca2+-ch. blocker;
ROA: i.v.;
IND: Tocolytic agent, Torsades-de-pointes, long QT syndrome, digitalis longus arrhythmias;
SEs: Maternal →fluching, lethargy, headache, pulmonary edema, cardiac arrest. Neonatal → Hypotension, respiratory depression

Question 8

Ethanol

Answer 8

IND: reduces uterine SMC contraction during labor and lactation

Question 9

Oxytocin

Answer 9

MOA: Induces uterine contraction (Gq effect)→oxytocin-R-agonist;
ROA: i.v, intranasal;
Effect: Secreted by post. pituitary gland → Uterus contraction +contraction of myoepithelial cells of breast (milk ejection);
IND: Induction and augmentation of labor, ↓postpartum uterine hemorrhage, induction of lactation;
SEs: Excessive uterine contraction → fetal distress, placental abruption, uterine rupture

Question 10

Ergotamine

Answer 10

MOA: α1/5HT-R agonist;
ROA: parentral;
Effect: Induce vasoconstriction and uterine contraction; IND: Prevent postpartum uterine hemorrhage;
Contra-IND: HTN, pregnancy;
SEs: prolonged tetany of myometrium, increased BP, angina

Question 11

Misoprostol

Answer 11

MOA: PGE1 analog;
ROA: p.o;
Effect: Uterus contraction, gastric mucus secretion; IND: Abortion (from 2nd trimester), induce labor, postpartum hemorrhage, prevent NSAID induced peptic ulcer;
SEs: Bleeding; Extra: Administered with mifepristone

Question 12

Tamsulosin

Answer 12

MOA: α1-selective antagonist (primarily in the GU tract);
ROA: p.o;
Effect: Relax muscle of prostate+bladder neck allowing urine to flow more easily

Question 13

Histamine

Answer 13

Function: Type I hypersenitivity reactions, inflammatory reactions, production of gastric acid, NT and neuromodulator;
Cells secreting/synthesizing HA: CNS neurons, Enterochromaffin cells, Mast cells, Basophils, Eosinophils;
HA-Rs: H1 (Gq), H2 (Gs), H3 (Gi), H4 (Gi)

Question 14

1st generation antihistamines:

Answer 14

Diphenyhydramine,
Dimetindene,
Chloropyramine

Question 15

Diphenyhydramine, Dimetindene, Chloropyramine

Answer 15

MOA: H1-receptor antagonists, also α1-AR, muscarinic, serotonergic antagonists;
ROA: p.o, parentral;
Effect: ↓vascular permeability, ↓nasal+bronchial mucus secretion, ↓bronchoconstriction;
IND: IgE-mediated allergies, asthma bronchiale, anaphylaxis, motion sickness, nausea, vomiting, dizziness, anorexia;
SEs: Sedation, cognitive impairement, Antimuscarinic- dry mouth, blurred vision, glaucoma exacerbation. Antiadrenergic- hypotension;
Extra: 1st generation can easily penetrate BBB→CNS effects

Question 16

2nd generation antihistamines

Answer 16

(Levo)cetrizine,
(Des)loratadine,
Fexofenadin

Question 17

(Levo)cetrizine, (Des)loratadine, Fexofenadin

Answer 17

MOA: H1-R-antagonists;
ROA: p.o, parentrally;
IND: IgE-mediated allergies (hay fever, urticaria, angioedema);
SEs: (milder than 1st gen.) sedation, at high dose→inhibit K+-ch.)
Extra: 2nd gen. does NOT penetrate BBB→ NO CNS effect