PAST QUESTIONS – V02. Obstetric Pharmacology (Click to Open)
SYLLABUS (Fourth Edition, 2023)
| LEVEL 1 | LEVEL 2 | LEVEL 3 |
|---|---|---|
| Oxytocics | ||
| Tocolytics |
N.B. The Syllabus tables used in our Pharmacopeia seem incomplete, but that is intentional because we have only included groups/classes/drugs which are mentioned directly in the syllabus or have been asked before in the exams.
TRAINEE EXPECTATIONS
- Trainees are expected to understand a drug’s pharmacology in the context of normal physiology, extremes of age (i.e., neonates, paediatrics, and the elderly), obesity, pregnancy (including foetal implications) and critical illness. An understanding of potential toxicity and relevant antidotes is also expected. Agents may be listed in more than one section when they are used for different indications.
- This is not an exhaustive list of all drugs relevant to or important in ICU practice. Each drug or classes of drugs have been assigned a details of understanding level outlined below. This is a guide to the minimum level of knowledge expected for that drug.
- For classes of drugs where examples are not specified, it is suggested a prototypical drug from the class be studied, as well as the relevant variations within the class exploring the major differences that exist between the agents in that class.
LEVELS OF UNDERSTANDING
| Level 1 | Level 2 | Level 3 |
|---|---|---|
| For these drugs, a detailed knowledge and comprehension of: | For these drugs a detailed knowledge of: | For these drugs a detailed knowledge of: |
| Class, Indications, and dose | ||
| Mechanism of Action | ||
| Pharmacodynamics and Adverse effects | ||
| Pharmacokinetics | Important pharmacokinetic differences or considerations when using in ICU | |
| Pharmaceutics | ||
CICMWrecks Tables (Click to Open)
MASTER TABLE
Pharmacopeia - Oxytocics & Tocolytics
| OXYTOCIN | ERGOMETRINE | CARBOPROST | BETA-2 AGONIST SALBUTAMOL | CCB NIFEDIPINE | NSAID INDOMETHACIN | MAGNESIUM SULPHATE | |
|---|---|---|---|---|---|---|---|
| GROUP | OXYTOCIC | OXYTOCIC | OXYTOCIC | TOCOLYTIC | TOCOLYTIC | TOCOLYTIC | TOCOLYTIC |
| CICM Level of Understanding | Level 3 | Level 3 | Level 3 | Level 3 for Tocolysis Level 2 for Bronchodilation (see in relevant table) | Level 3 for Tocolysis Level 3 for anti-hypertensive (see in relevant table) | Level 3 for Tocolysis (NSAIDs Level 3 for Pain. Indomethacin Not included in that table) | Level 3 for Tocolysis Level 1 for Electrolytes and Buffers |
| INTRODUCTION | Glycopeptide | Ergot Alkaloids | Prostaglandin PG-F-2alpha synthetic analogue | synthetic sympathomimetic amine | dihydropyridine derivative | indole-acetic acid derivative | Electrolyte |
| USES | 1. Induce or augment labor 2. Facilitate delivery of placenta 3. PPH 4. Miscarriage | 1. Prevention and treatment of PPH 2. Termination of pregnancy 3. Facilitate delivery of placenta | 1. Treatment of PPM 2. Termination of pregnancy | uncomplicated preterm labour (Asthma, COPD) | Suppression of threatened or established preterm labour before 34 weeks gestation where not contraindicated. (Angina, HTN, PIH, Raynaud’s, Coronary spasm during angio) | early preterm labor (< 30 wk) or preterm labor associated with polyhydramnios (Other NSAID uses) | Premature Labour (however no evidence that it delays delivery) Helpful in pre-eclampsia (neuroprotection) |
| PHARMACODYNAMICS (PD) | |||||||
| PD: Main Action | 1. Oxytocin GPCR → IP3/DAG increase calcium in uterus promoting uterine contraction 2. Cervical dilation | Uterine contraction, mechanism unknown (likely serotonin mediated) | Most potent oxytocic | ↑ myometrium cAMP (GsPCR) → increased cAMP → uterine SM relaxation | -Inhibition of L-type calcium channels leads to decreases myometrial SM → decreased SM contraction | Decreased synthesis of PGE2 and PGF-2-alpha leading to decreased contraction of smooth muscle | Unclear. Possible explanation: Antagonises Ca2+ activity in uterine muscle cells → relaxation |
| PD: Side Effects / Toxicity | 1. Mild diuretic effect with hyponatraemia if hypotonic fluids used (similar to vasopressin) 2. Hypotension if bolus given (generally 5U slow push) 3. Administration via IV lines as blood/plasma may lead to rapid inactivation by plasma oxytocinase 4. Uterine rupture if excessive doses administered rapidly | 1. Hypertension 2. Peripheral vasoconstriction 3. Headache | 1. Bronchoconstriction 2. Severe hypertension 3. Cardiac collapse | Fetal Tachycardia Maternal Tachycardia/Palpitations/Arrhythmia, tremors, hypokalaemia, hyperlactataemia, hyperglycaemia. | Inhibition of hypoxic pulmonary vasoconstriction, Impaired platlet aggregation, Headache, flushing and dizziness, Peripheral oedema | - Maternal A/E: GIT upsets, renal impairment, asthma - Fetal A/E: constriction of ductus arteriosis, pulmonary hypertension, reversible decrease in renal function (oligohydramnios) | Toxicity: • Somnolence, areflexia, AV and intraventricular conduction disorder • Progressive muscular weakness • Cardiac arrest • Reversal of toxicity with Calcium administration |
| PHARMACOKINETICS (PK) | IV or IM T1/2= 3-5min (rapidly hydrolyzed by plasma oxytocinases) | IM often in combination with oxytocin Uterine contraction seen within minutes of IM and lasts 6 hours Metabolized by liver and excreted in bile | IM, IV or intra-myometrium | IV infusion: 10mcg/minute and uptitrate slowly to 10mcg/min Should not be used together with Nifedipine | PO Loading – 20mg, further 2 doses 30minly if contractions persist Maintenance 20-40mg QID for up to 48hrs Should not be used together with Salbutamol | Loading: 50-100 mg PR Maintenance: 25-50mg PO Q6-8hrly | Based on protocol: Loading ~4gm → Infusion 2-4gm/hr Monitoring: cardiac, clinical, serum levels Potential hypotension when used with nifedipine. Care with indomethacin. |
Search bar: To search for something particular within the table.
Recent Comments