drugs used in labour

1. DRUG USE IN LABOUR
Kalpana Lamsal
BNS 2nd Year
Roll no:14

2. Contents
• Anticonvulsant drugs
• Anti- Coagulant drugs
• Vitamin K

3. ANTI- CONVULSANT DRUGS
• Convulsion is defined as a group of disorders in which there
are recurrent episodes of altered cerebral function which may
or may not associated with loss of consciousness.
• Convulsion on pregnancy or during labor is due to eclampsia.
• Other causes of convulsion includes:
• Epilepsy
• Meningitis
• Cerebral Malaria
• Cerebral Tumors

4. Contd…
• The optimum treatment of the convulsion requires that the
most appropriate anticonvulsant drug.
• This requires knowledge of specific convulsion syndromes
and also anticonvulsant drug pharmacokinetics before,
during and after pregnancy.
• Any adverse effect that the anticonvulsant drug could have
on the developing child needs to be avoided or minimized
during pregnancy. labor and lactation.

5. Common drugs:
COMMONLY USED DRUGS ARE:
1. MAGNESIUM SULPHATE
2. DIAZEPAM
3. PHENYTOIN

6. MAGNESIUM SULPHATE
• Magnesium sulphate is a minerals or drugs.
• A potent vasodilator
• Laxatives
• Tocolytic agents.

7. Cont…
• Magnesium sulphate is first drug of choice used since many
years to reduce the maternal complication due to eclampsia
and severe pre eclampsia in obstetrics .

8. MECHANISM OF ACTION
• It decreases the acetylcholine release from the nerve ending
and reduce the motor end plate sensitivity to acetylcholine .
It trigger the cerebral vasodilation , dilates uterine artery
inhibit platelet aggregation . This also block the entry of
calcium into synaptic ending.

11. MECHANISM OF ACTION

12. Competitive inhibition to calcium ion either
at motor end plate or at the cell membrane
Reduces calcium influx
Decreases acetylcholine release and its
sensitivity at the motor end plate
Direct depressant action on uterine muscles

13. SIDE EFFECT:
• Muscle weakness
• Respiratory depression
• Somnolence
• Dizziness
• Irritation

14. DOSE
LOADING DOSE
• Magnesium sulphate 20% solution , 4gm IV over 5 minutes.
• Follow promptly with 10gm of 50% magnesium sulphate solution
, 5gm in each buttock as deep IM injection with 1ml 2% xylocaine
in the same syringe .
• If further fits occur, give further 2 ampoules of MgSo4
50%=4ml=2gm IV slowly over 5 minutes

15. MAINTENANCE DOSE
• 5gm magnesium sulphate 50 % + 1ml xylocaine 2% IM every
4hours into alternate buttocks.
• Continue for 24 hours after delivery or last convulsion which
occurs last.

16. Before repeating MgSo4 always monitor for Toxicity
• Respiratory rate<16/minute
• Patellar reflexes absent
• Urine output <30 ml/hour

17. If Respiratory Arrest:
• Assist ventilation with bag and mask or intubation
• Give calcium gluconate 1 gm (10 ml of 10%) IV slowly until
respiration begins.

18. Adverse Effects:
Maternal Effects:
• Flushing, nausea, vomiting, headaches
• Dizziness
• Diaphoresis
• Hypotension

19. Adverse Effects contd….
• Diminished deep tendon reflexes
• Respiratory depression
• Circulatory collapse
• Muscle weaknes,
• Blurred vision
• Intravenous (IV) or intramuscular (IM) site pain or
discomfort

20. Fetal effects:
• Decreased fetal heart rate variability
• Respiratory depression
• Motor depression
• Low APGAR score at birth
• Long bone calcium demineralization
• Osteopenia and fracture

21. NURSING INTERVENTION
• Assess the patient vital signs in every 15 minutes.
• Monitor the level of magnesium
• Monitor the time of contraction and its intensity if using it on
labor.
• Urine output should remain 30ml/hour and if less notify
physician.
• Examine patient reflexes- knee jerk reflex, patellar reflex.
• Make sure the Calcium gluconate is radially available in case of
toxicity.
• Provide seizure precaution- keep patient in single room with
decreased stimuli, padded siderails.

22. NURSING INTERVENTION
• Positioning patient in left lateral recumbent position to
decrease hypotension and increase renal blood flow.
• Evaluate patient mental status, sensorium, memory and
respiratory status.
• Before repeat administration , ensure toxicity.
• Discontinue drugs if respirations are less than 12b/min,
reflexes severely hypotonic, urine output less than
30ml/hour or in the event of mental confusion, lethargy and
fetal distress.

23. NURSING INTERVENTION
• Incase of respiratory arrest assist ventilation.
• Give calcium gluconate 1gm 10 ml of 10% solution iv slowly
until respiration begin to antagonist the effect of mgso4.

24. DIAZEPAM
• It is centrally long acting muscle relaxant drug.
• It acts on GABA receptor complex in limbic system
• It Binds specific benzodiazepine receptor site in limbic system,
thalamus, hypothalamus and brain stem which elevate the
seizure threshold in response electric chemical stimulants.
• It inhibits spinal afferent pathway, producing skeletal muscle
relaxation.

25. Mechanism of Action

26. INDICATION
• Severe pre-eclampsia
• eclampsia

27. Dose
Loading dose :
• Initially 20-40 mg IV slowly over 2 minutes .

28. MAINTAINENCE DOSE
• Diazepam 40 mg in 500ml ringer lactate. The drip rate being
30drops/min to maximum 3 mg/kg over 24 hours.

29. Cont…
SIDE EFFECT :
MOTHER:
• hypotension
• Dizziness
• Drowsiness
• Headache
FETUS : respiratory depressant effect which may last for even
three weeks after delivery .
NEWBORN:Hypotonia, Thermoregulatory problem.

30. Contraindications
• Acute narrow angle glaucoma
• Acute alcohol intoxication
• Lactation

31. Caution
Impaired kidney / liver function

32. NURSING CONSIDERATION
• Assess Blood Pressure in lying and standing position , if systolic
pressure falls 20 mm of Hg hold drug and inform physician .
• Assess blood studies – CBC and hepatic study
• Administer IV large vein .
• Don't give oral drug with milk or food to avoid GI symptoms.
• Evaluate therapeutic response eg: mental status , sensorium ,
sleeping pattern , physical dependence , headache , nausea ,
vomiting

33. Contd…
Teach patient and family about:
• The drug may taken with food .
• Avoid alcohol consumption.

34. PHENYTOIN
• It is centrally acting anticonvulsant drugs.
• It is prescribed for the prevention of focal seizures , generalized
tonic-clonic seizures and for the acute treatment of status
epilepticus
Mechanism of action
Neuron Membrane stabilization by blocking Na+ and Ca++
influx into the neuronal axon. Or inhibits the release of
excitatory amino acids via inhibition of Ca++ influx.

35. DOSE
• Eclampsia
10 mg /kg IV at the rate not more than 50 mg /min
followed 2 hours later by 5mg /kg. Followed by
maintenance dose of about 100mg is given at interval of 6-
8 hours.
• Epilepsy
300-400 mg daily in divided doses.

36. SIDE EFFECT
MATERNAL :
• Hypotension
• Cardiac arrhythmia
• phlebitis at injection site
• GI upset, Headache, vertigo, ataxia, sedation.
FETUS:
• Fetal hydantoin syndrome: syndromic

39. NURSING CONSIDERATION
• BLOOD STUDIES :CBC, platelets, every 2 weeks until
stabilized.
• Discontinue drug if neutrophil less than 1600/mm3
• Administer after diluting with normal saline.
• Evaluate mental status , sensorium , effect ,memory .
Respiratory depression , sore throat , bruising
• Teach patient and about all aspect of drug administration,
when to notify physician.

40. NURSING CONSIDERATION
• Assess blood studies , liver function test during intake
of drug.

42. Anticoagulant drug
• Anticoagulant drugs are not commonly used in pregnancy.
• The ideal anticoagulant drug would prevent pathologic
thrombosis and limit reperfusion injury yet allow a normal
response to vascular injury and limit bleeding

45. Commonly used drugs:
• Heparin
• Warfarin

46. HEPARIN
Heparin is an injectable and rapidly acting anticoagulants. It
cannot be given in oral routes as it destroyed by gastric juices.
MECHANISM OF ACTION:
• The active heparin molecules bind tightly to antithrombin
• Antithrombin markedly inhibit blood coagulation by
inhibiting all factors, especially thrombin and factor Xa,
which prevents conversion of fibrinogen to fibrin.

48. INDICATIONS
• Deep vein thrombosis
• Thromboembolism
• Disseminated intravascular coagulation
• patient with prosthetic valve in the heart.

49. DOSE
5,000-10,000 IU subcutaneous to be administer 12 hourly
with monitoring during pregnancy.

50. SIDE EFFECT:
Maternal:
• Hemorrhage
• Urticaria With Long Term Use
• Thrombocytopenia
• Osteoporosis
• Alopecia
• Leukopenia
FETAL: It doesn’t cross the placenta

51. NURSING CONSIDERATION
Assess blood studies – hematocrit , platelet , occult blood in
stools.
• Assess partial prothrombin time and blood pressure – sign of
hypertension
• Administer at same time each day to maintain steady blood
level.
• Avoid IM injection that may cause bleeding .
• Evaluate therapeutic response – decrease of deep vein
thrombosis .
• (Protamine sulfate )Antidote of Heparin should be readily
available.

52. Cont…
• Evaluate bleeding gums , petechiae, ecchymosis , black tarry
stool , hematuria , fever , rashes , urticaria.
• Teach patient /family
To avoid use of drugs unless prescribe by physician.
To use soft bristle toothbrush to avoid bleeding gums.
 To comply with instructions.
To report any sign of bleeding –gums under skin , urine , stool.

53. WARFARIN
In the 1950s, warfarin (under the brand name Coumadin) was
introduced as an antithrombotic agent in humans. Warfarin is
one of the most commonly prescribed drugs.
warfarin is bound to plasma albumin.
It has long half-life in plasma (36 hours).

54. MECHANISM OF ACTION:
• Interfere with the synthesis of vitamin K dependent factor (
II, VII, IX,X) results in incomplete clotting.

56. INDICATION:
• Acute deep vein thrombosis
• Pulmonary embolism
DOSE:
10 mg orally for initial 2 days then 3-9 mg daily

57. SIDE EFFECTS:
MATERNAL
• Hemorrhage

58. FETAL:
• Contradi’s Syndrome
• Optic Atrophy
• Microcephaly
• Warfarin Embryopathy (5%)
• Nasal Hypoplasia
• Bone Stippling
• Mental Retardation
• Chondrodysplasia Punctata

59. Toxicity
• Warfarin crosses the placenta readily and can cause a
hemorrhagic disorder in the fetus.
• the drug can cause a serious birth defect characterized by
abnormal bone formation.

60. Cont…
NURSING CONSIDERATION
• Assess blood studies – hematocrit , platelet, occult blood in
stool , prothrombin time.
• Administer at same time , do not give with food.
• Avoid IM injection that may cause bleeding .
• Evaluate therapeutic response – decrease of deep vein
thrombosis .

61. Cont…
• Evaluate bleeding gums , petechiae, ecchymosis , black tarry
stool , hematuria , fever , rashes, urticaria.
Teach patient and family:
• To avoid over the counter prescription unless prescribe by
physician.
• Drug may be held during menstruation
• To use soft – bristle tooth brush.
• To report any sign of bleeding.

62. Vitamin K(phytonadione)
• Vitamin K confers biologic activity upon prothrombin and factors
VII, IX, and X by participating in their post ribosomal
modification.
• Vitamin K is a fat-soluble substance found primarily in leafy
green vegetables.
• The dietary requirement is low because the vitamin is
additionally synthesized by bacteria that colonize in the human
intestine.
• Two natural forms exist: vitamins K1 and K2. Vitamin K1
(phytonadione is found in food. Vitamin K2 (menaquinone) is
found in human tissues and is synthesized by intestinal bacteria.

63. • At birth, newborn does not have bacteria in the colon that is
necessary for synthesizing fat soluble vitamin K.
• Therefore newborn have low level of prothrombin during
first 5 days of life.
• Vitamin K1 is currently administered to all newborns to
prevent the hemorrhagic disease of vitamin K deficiency,
which is especially common in premature infants.

64. Mode of action
• It promotes the hepatic formation of clotting factor II, VII, IX
and X.

65. Indication
• It is used to treat certain bleeding disorder
• It helps liver to produce blood clotting factor.

66. Contraindication
• Hypersensitivity

67. Adverse Reaction
• Pain and edema may occur at injection site.
• Allergic reaction
• urticaria
• Hyperbilirubinemia

68. Doses
• 1 Mg within 1 hour of birth.

69. Nursing Consideration
• Observe for bleeding usually occur on 2nd and 3rd day.
• Observe for local edema.

71. summary

72. References
Katzung, B. (2018). Basic and Clinical Pharmacology (14th ed.). Mc Grow
Hill Education.
Konar,K.(2019).DC Dutta’s Textbook of Obstetrics(9th ed.).New Delhi.
jaypee brothers.
Tuitui, R. (2015). Manual of midwifery II (11th.). Vidyarthi Pustak
Bhandar.
Thapa, R. (2013). A Companion Pocket Book Of Pharmacy (4th ed.).
Taleju Prakashan.
Hossain, S. (2015). Systemic Pharmacology (12th ed.). Bishaw Bani
Prakashoni.

73. Thank You