Administrating medications and drug calculations

Administering medications

Sarah Stewart 2012

http://www.flickr.com/photos/47852054@N00/50275040

Responsibilities of the midwife in the administration of medicines

To administer medications according to a prescription

To maintain proper documentation of both prescription and non-prescription drugs

To use proper techniques when administering medications by the various routes


Woman’s or baby’s identity The midwife must verify that

the right woman/baby is receiving the right medicine for whom it is prescribed

Check that the details on the woman’s/baby’s identity band match the medication chart

Ask the woman to verify her personal details, for example name and date of birth


Prescription charts The generic name of the

drug (not the trade name); The dose to be given; The time for

administration; The route of

administration. The prescription should

be legible & unambiguous, signed & dated by the prescribing practitioner.


The prescription chart should be labelled with the name, date of birth and hospital identification number.

Any known allergies. Weight recorded on

the prescription sheet for any weight-related dosages


Checking the medication Policies around appropriate

practitioner and number of practitioners needed to check medication may vary

Exceptions are controlled drugs and medicines for children

Check generic name of the drug

The dose required The time for administration


That the drug has not already been given

That the prescription is legible, signed and dated

The expiry date of the drug

The woman has no known allergy or sensitivity to the drug


Administration of medicines

Medicines should be dispensed into a clean, dry and preferably disposable container

Where liquid preparations are used, these should be measured using syringes specifically designed for this purpose

Informed consent should be sought with assessment of the woman’s knowledge of the medication

Women have the right to refuse this and should be documented where it occurs

The woman should be helped into a comfortable position especially if she has had surgery

If the medication is not due to be taken or if the woman is not ready to take it then it should be returned to the drug cupboard, it MUST NOT be left out for the woman to take later

Medications should be given in the prescribed manner and tablets should never be crushed

6 Rights

Right drug

Right woman/baby

Right time

Right dose

Right route

Right to refuse/decline


Drug calculations


Converting decimals 1kg (kilogram) = 1000 (gram) 1g (gram) = 1000 mg (milligram) 1mg (milligram) = 1000 mcg (microgram) 1mcg (microgram) = 0.0001 mg

To convert:g to mg – x by 1000 g to kg divide 1000mg to mcg x by 1000 mg to g divide 1000kg to g x 1000 mcg to mg divide1000

Change 0.64 grams to mg

Change 1500mg to grams

Change 0.043 mg to micrograms

Change 0.64 grams to mg0.64 / 1000 = 640 mg (move decimal point 3 places to right)

Change 1500mg to grams 1500 x1000 = 1.5g (move decimal point three places to left)

Change 0.043 mg to micrograms 0.043 x1000 = 43 mcg (move decimal point 3 places to right)

A woman you are caring for in the ante natal ward has severe symphysis pubis dysfunction and is prescribed 60 milligrams of Codeine phosphate. 30 milligram tablets are available. How many tablets will you give?

You are asked to administer 400000 micrograms of oral Metronidazole to a woman who has mastitis 1 week after giving birth, but the tablets come as 200 milligram tablets. How many tablets do you require?

You are asked to give a woman an injection of benzylpenicillin to treat her wound infection, 7 days following caesarean section. The prescription says administer 600 milligrams. You have vials of medication with several doses - which vial do you give?

Answer

a. 5 ml vial containing 1 million IU (equivalent to approximately 0.6 g benzylpenicillin)

b. 10 ml vial containing 2 million IU (equivalent to approximately 1.5 g benzylpenicillin sodium)

c. 15 ml vial containing 5 million IU (equivalent to approximately 3 g benzylpenicillin sodium)

d. 30 ml vial containing 10 million IU (equivalent to approximately 6 g benzylpenicillin)

Dose (what you want) X What it is in

Stock (what you have) 1

You are caring for a woman in labour who is very sick so you decide to give her an anti-emetic. The standing order is for the administration of Stemetil 15 mg. You have 2 ml solution which contains 25 mg Stemetil. What volume do you give?

You are asked to give a dose of 75 mg of pethidine to a woman who has just had a c/section. It is available in ampoules containing 100 mg in 2 ml. What volume will you give?

You are required to administer intramuscular Narcan to a new born baby that has been heavily affected by maternal pethidine - his body weight is 3.5 kg. The prescription for Narcan is 0.01mg/kg of the baby's body weight. Narcan presents as 0.02mg/mL. How many mls do you administer?

You are asked to work out the dose for IM Gentimicin for a pregnant woman who has a severe respiratory infection at 36 weeks gestation. The formula is 3mg/kg/day. The woman's weight is 75kg. What is the dose you would give every 8 hours?

You are asked to administer 35 milligrams of Codeine phosphate by subcutaneous injection to a pregnant woman who has cholecystitis at 34 weeks gestation. 50 milligrams in 1 millilitre of liquid for SC Injection is available. How many millilitres will you administer?

Intravenous infusion calculations

Work out IV flow rates

as drops per minute.

Before you start, you

need to know the drop

factor of the giving set

-that can be found on

the packaging


Volume (mls) x drop factor = drops per minute

Time (minutes)

You have been asked to administer 1000 ml IV Saline over 12 hours to Mrs Jones following her c/section. Using a drop factor of 15 drops / ml, how many drops per minute need to be delivered?

A woman you are caring for 2 days following a PPH requires a blood transfusion. She is required to have a unit (450 mls) blood over 3 hours using a blood giving set with a calibration of 10 drops per ml. How many drops per minute do you set the running rate?

Resources

http://www.testandcalc.com

Queensland Health Drug Therapy Protocol for Midwives: http://www.health.qld.gov.au/ph/documents/ehu/dtp-midwives.pdf

Midwifery Essentials. J. Gray & R.Smith. 2008. Elsevier.

http://www.testandcalc.com/

http://www.health.qld.gov.au/ph/documents/ehu/dtp-midwives.pdf

Administrating medications and drug calculations

Health & Medicine

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