Description of Oxytocics, Tocolytics and Related Medicines – PST04211 Basic Pharmacology

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NTA Level 4 • Semester 2 • PST04211

Description of Oxytocics, Tocolytics and Related Medicines

Basic Pharmacology • Source Session/Topic 43
Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability.

Session 43: Description of Oxytocics, Tocolytics and

Related Medicines

Total Session Time: 120 minutes

Prerequisites

• None

Learning Tasks

By the end of this session students are expected to be able to:

• List indications of essential oxytocics, tocolytics and related preparations
• List contraindication of essential oxytocics, tocolytics and related preparations
• Describe dose, dosage and course of essential oxytocics, tocolytics and related

preparations

• List common side effects and adverse effects of essential oxytocics, tocolytics and related

preparations

• Describe interactions and precautions of essential oxytocics, tocolytics and related

preparations

Resources Needed:

• Flip charts, marker pens, and masking tape
• Black/white board and chalk/whiteboard markers
• Computer and projector

SESSION OVERVIEW

Activity/

Step Time Content

Method

1 05 minutes Presentation Introduction, Learning tasks

Presentation/ Clinical Indications of Oxytocics, Tocolytics

2 20 minutes

Buzzing and Related Preparation

Presentation/ Contraindications of Oxytocics, Tocolytics

3 20 minutes

brainstorming and Related Preparation

Dose, Dosage and Course of Oxytocics,

4 30 minutes Presentation

Tocolytics and Related Preparation

Presentation/ Common Side Effects and Adverse Effects of

5 20 minutes

brainstorming Oxytocics, Tocolytics and Related Preparation

Interaction and Precaution of Oxytocics,

6 15 minutes Presentation

Tocolytics and Related Preparation

7 05 minutes Presentation Key Points

8 05 minutes Presentation Evaluation

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SESSION CONTENTS

STEP 1: Presentation of Session Title and Learning tasks (5 minutes)

READ or ASK students to read the learning objectives and clarify

ASK students if they have any questions before continuing.

STEP 2: Clinical Indications of Essential Oxytocics, Tocolytics and Related

Preparations (20 minutes)

Activity: Buzzing (5 minutes)

ASK students to pair up and buzz on the following question for 2 minutes

• What are the clinical indications of essential oxytocics, tocolytics and related

preparations?

ALLOW few pairs to respond and let other pairs to add on points not mentioned

WRITE their response on the flip chart/board

CLARIFY and SUMMARIZE by using the content below

• According to Tanzania Standard treatment guideline, essential oxytocics, tocolytics and

related preparations include salbutamol, ergometrine, oxytocin, misoprostol and

magnesium sulphate

Salbutamol

• Salbutamol is used for myometrial relaxation
• It is used in selected cases in attempt to inhibit premature labor once it has begun.

Ergometrine

• Its main action is the production of intense contractions
• It is used in the active management of the third stage of labor, and to prevent or treat

postpartum or postabortal haemorrhage caused by uterine atony

• Ergometrine maleate or methylergometrine maleate have been used in a provocation test

for the diagnosis of Prinzmetal's angina

Oxytocin

• Synthetic oxytocin is the most widely used drug for stimulating uterine contractions

following the rapture of membranes during labor

• It is also used to augment abnormal labor that is protracted or displays arrest disorder.
• Oxytocics used in the immediate postpartum period, including the control of uterine

hemorrhage after vaginal or cesarean delivery (Postpartum Haemorrhage – PPH)

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Misoprostol

• It is commonly used for labor induction
• It causes uterine contractions and the ripening (effacement or thinning) of the cervix
• It is also used to prevent and treat stomach ulcers, and treat postpartum bleeding due to

insufficient contraction of the uterus

Magnesium Sulphate

• Used as a tocolytics to stop preterm labor and for severe pre-eclampsia

STEP 3: Contraindication of Essential Oxytocics, Tocolytics and Related

Preparation (20 minutes)

Activity: Brainstorming (5 minutes)

Ask students to brainstorm on the following question:

• What are the contraindications of essential oxytocics, tocolytics and related

preparation?

ALLOW few students to respond

WRITE their responses on the flip chart/ board

CLARIFY and SUMMARISE by using the content below

Salbutamol

• Salbutamol is contraindicated in the suppression of labor in women with heart disease,

eclampsia or severe pre- eclampsia, antepartum haemorrhage or placenta previa

• It should be used with caution in women with diabetes, hypertension or hyperthyroidism

Oxytocin

• Oxytocin is contraindicated in women, for whom vaginal delivery is contraindicated

because of conditions such as unfavorable foetal position (e.g. transverse lie) or placenta

previa – a condition in which the placenta grows over the cervix, blocking the baby‘s exit

Ergometrine

• Ergometrine maleate is contra-indicated for the induction of labor or for use during the

first stage of labor

• Ergometrine maleate has been associated with acute attacks of porphyria and is

considered unsafe in porphyric patients

Misoprostol

• Misoprostol is contraindicated in Pregnancy when used to reduce risk of NSAID-induced

ulcers and to individuals with hypersensitivity to misoprostol, prostaglandins, or

prostaglandin analogues

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Magnesium sulphate

• Magnesium sulphate is contraindicated in the patients with the following conditions:-

o Hypersensitivity, myocardial damage, diabetic coma, heart block, hypermagnesemia,

hypercalcemia

• Administration during 2 hours preceding delivery for mothers with toxemia of pregnancy

STEP 4: Dose, Dosage and Course of Essentail Oxytocics, Tocolytics and

Related Preparation (30 minutes)

Salbutamol

• 10 micrograms per minute of Salbutamol is given and gradually increasing to 45

micrograms per minute until contraction has ceased and then reduce gradually

• Alternatively, give by IM injection 100 -250 micrograms and repeat according to the

patient response and subsequently, give orally 4mg every 6 to 8 hours as maintenance

dose

• Salbutamol is administered by IV infusion using dextrose 5% until 12 to 48 hour after

contractions have ceased, followed by oral maintenance therapy

Oxytocin

• For induction of labor use: Oxytocin IV the dose will depend on parity

o Primigravida:

 Oxytocin IV 5 IU in 500mls of fluid titrate at 15, 30, 60 drops per minute until

desired uterine contractions are attained

o Multiparous:

 Oxytocin IV Starts with low dose eg 1.25 IU in 500mls of fluid titrate as above.

Regulate the dose according to response

 If no progress of labor is achieved give; Oxytocin (IV) Initially 1 unit then 4 units

in 1 litre Normal Saline at 15, 30, 60 drops per minute until regular contractions

lasting for more than 40 secondly are maintained

• When 4 units are not enough to cause maintained constructions, and it is first pregnancy,

the dose can be increased to 16, 32 then 64 units in litre of Normal Saline each time

increasing the delivery rate through 15, 30 and 60 drop per minute

Ergometrine

• Ergometrine maleate alone is used for prevention or treatment of postpartum or

postabortal haemorrhage in a usual intramuscular dose of 200 micrograms

• A dose of ergometrine maleate 500 micrograms and oxytocin 5 units is injected

intramuscularly after delivery of the anterior shoulder, or, at the latest, immediately after

delivery of the infant; contractions are reported to occur within 2 to 7 minutes.

• Single doses of 250 to 500 micrograms have also been used
• In the treatment of mild secondary postpartum haemorrhage, ergometrine maleate has

been given by mouth in a dose of 500 micrograms three times daily for 2 to 7 days

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Misoprostal

• For induction of labor
o 25 mcg (1/4 of 100-mcg oral tablet) intravaginally initially, then repeat at intervals not

to exceed q3-6hr

o Not to be used in patients with previous cesarean delivery or major uterine surgery

• Postpartum Hemorrhage (Off-label)
o Prophylaxis: 600 mcg PO within 1 minute of delivery
o Treatment: 800 mcg PO once; use caution if prophylactic dose already given and

adverse effects present or observed

o Use only in settings where oxytocin not available

Magnesium Sulphate

• For management of Severe pre-eclampsia
o Magnesium sulphate is used together with normal saline, nifedipine 10-20 mg 12 hrly
and Hydralazine 10 mg (I.V) slowly in the following dose

o Magnesium sulphate 4gm (IV) in 20 mls of normal saline for 10-15 min followed by

5gm of 50% MgSO4 in each buttock; Followed by 4gm of MgSO4 in 250 mls of

normal Saline to run over 4hrs. Maintenance dose: 4gm of MgSO4 (IM alternative

buttock) 4hourly for 24hrs

o MgSO4 regimen should continue until 24 hrs after the last fit

STEP 5: Common Side Effects and Adverse Effects of Essential Oxytocics,

Tocolytics and Related Preparation (20 minutes)

Activity: Brainstorming (5 minutes)

Ask students to brainstorm on the following question:

• What are the side effects and adverse effects of essential oxytocics, tocolytics and

related preparation?

ALLOW few students to respond

WRITE their responses on the flip chart/ board

CLARIFY and SUMMARISE by using the content below

Adverse effects of salbutamol

• Salbutamol may cause possible adverse effect in the mother, this includes tachycardia,

tremor, palpitations, nausea and vomiting, thirsty, restlessness, hypertension, flushing and

hyperglycaemia

• It can cause oedema though rarely and this is usually due to fluid overload and can be

avoided by giving Salbutamol in small volumes of fluid only

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• Myocardial ischaemia is also rare but serious complications

Adverse Effects of oxytocin

• Includes hypertension, arrhythmia and pulmonary oedema
• Hyperstimulation of the uterus is the main complication of oxytocin infusion
• This may lead to uterine rapture, amniotic fluid embolism or foetal distress
• If signs of hyperstimulation are noticed, oxytocin administration should be stopped

immediately

Adverse Effects of ergometrine

• Nausea and vomiting, abdominal pain, diarrhoea, headache, dizziness, tinnitus, chest

pain, palpitations, bradycardia and other cardiac arrhythmias, myocardial infarction,

dyspnoea, and pulmonary oedema have been reported after use of ergometrine

• Bronchospasm has been reported after use of ergometrine
• Hypertension may occur, particularly after rapid intravenous dosage; hypotension has

also been reported. Hypersensitivity reactions, including shock, have occurred

• Ergometrine shows fewer tendencies to produce gangrene than ergotamine, but ergotism

has been reported and symptoms of acute poisoning are similar

Adverse effects of misoprostol

• The most commonly reported adverse effect of taking a misoprostol orally is diarrhea,

abdominal pain, nausea, flatulence, headache, dyspepsia, vomiting, and constipation

Common Side Effects of Intravenous Magnesium sulphate

• Common side effects of intravenous magnesium sulphate includes respiratory paralysis,

hypothermia, pulmonary edema, depressed reflexes, hypotension, flushing, drowsiness,

depressed cardiac function, diaphoresis, hypocalcemia, hypophosphatemia, hyperkalemia,

visual changes

STEP 6: Description of Interaction and Precaution of Essential Oxytocics,

Tocolytics and Related Preparation (20 Minutes)

Oxytocin

• Precautions

o If uterine hyperactivity occurs, discontinue immediately

o Intravenous preparations should be administered by trained personnel

o Risk of severe water intoxication on prolonged administration due to its antidiuretic

effects

o Restricting fluid intake may be warranted

o Uterine hypertonicity, spasm, rupture of the uterus, and tetanic contractions may

occur from high doses

o IM not recommended for labor induction/augmentation

Misoprostol

• Warning

o Patients must seek medical attention if excessive bleeding occurs

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o Administration to pregnant women can cause abortion, premature birth, or birth

defects

o Uterine rupture has been reported when drug is administered to pregnant women to

induce labor or induce abortion beyond 8th week of gestation

o Do not use for reducing risk of NSAID-induced ulcers in women of childbearing

potential unless patient is at high risk for complication from gastric ulcers; may be

prescribed in the following situations:

Magnesium sulphate

• Warnings

o Magnesium sulfate (magnesium sulfate (magnesium sulfate injection) injection)

should be given very cautiously in the presence of serious impairment of renal

function since it is excreted almost entirely by the kidneys

• Precautions

o When barbiturates, narcotics, or other hypnotics (or systemic anesthetics) are to be

given in conjunction with magnesium, their dosage should be adjusted with caution

because of the additive central depressive effects of magnesium

o Hypomagnesemia is usually associated with hypokalemia (potassium levels must be

normalized)

STEP 7: Key points (5 minutes)

• According to Tanzania standard treatment guideline, essential oxytocics, tocolytics and

related preparations include salbutamol, ergometrine, oxytocin, misoprostol and

magnesium sulphate

• Synthetic oxytocin is the most widely used drug for stimulating uterine contractions

following the rapture of membranes during labor

• Common side effects of intravenous magnesium sulphate includes respiratory paralysis,

hypothermia, pulmonary edema, depressed reflexes, hypotension, flushing, drowsiness,

depressed cardiac function, diaphoresis, hypocalcemia, hypophosphatemia, hyperkalemia,

visual changes

STEP 7: Evaluation (5 minutes)

• What are the clinical indications of Oxytocin and Magnesium sulphate?
• What are the common adverse effects of salbutamol, misoprostol and ergometrine?
• What are the contraindications of oxytocin and misoprostol?

PST 04211 Basic Pharmacology NTA Level 4 Semester 2 Facilitator Guide

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References

Ministry Of Health and Social Welfare. (2013). Standard Treatment Guidelines & National

Essential Medicines List Tanzania Mainland (4th ed.). Dar es salaam, Tanzania

government printers.

Robert L. Talbert, Gary C. Yee, Gary R. Matzke, Barbara G. Wells & L. Michael. (2014).

Pharmacotherapy: a pathophysiologic approach (9th ed.). New York, McGraw-Hill

Education.

Sally S.R & Jeanne C.S. 2000. Introductory Clinical Pharmacology (6th ed) New York,

Lippincott Williams and Wilkins.

School of Pharmaceutical sciences.( 2011).Tanzania Pharmaceutical Handbook (2nd ed.).

Dar Es Salaam, ARDHI University press.

The Royal Pharmaceutical Society of Great Britain. (2007). Martindale, the Extra

Pharmacopoeia (5TH ed). London, pharmaceutical press.

PST 04211 Basic Pharmacology NTA Level 4 Semester 2 Facilitator Guide

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