DRUGS IN PREGNANCY

• In short-term tocolysis (maximum 48 hours) before the thirty-second week of pregnancy, this is seldom problematic, although the magnitude of the risks is still a subject of debate.
• Instances in which inhibition of uterine contractions would be appropriate and desirable for good pregnancy outcome include preterm labor, patient transfer to a tertiary care center, fetal distress associated with contractions, hypertonic uterine contractions, placenta previa when mild bleeding is associated with contractions, and when any surgical procedure is contemplated during pregnancy and carries the risk of preterm labor.
• Tocolytic agents can stop uterine contractions and temporarily delay delivery.
• Among the most common agents used as tocolytics are β-adrenergic agents, calcium channel blockers, magnesium sulfate, oxytocin receptor antagonists, and prostaglandin antagonists.
• This group of sympathomimetics includes ritodrine, terbutaline, salbutamol and adrenaline.
• These drugs act, like adrenaline, by stimulating the beta2 receptors which are present in the liver and the smooth muscle and glands of many organs, including the uterus, lungs and gut.
• There is also pronounced action on the beta2 receptors, which stimulate the heart, in a manner similar to adrenaline/epinephrine and noradrenaline (norepinephrine).
• Due to individual differences, doses of Beta2 Adrenoreceptor Agonists are adjusted according to response and side effect monitoring.
• Cardiovascular System: Cardiovascular stimulation such as increase heart rate, pulse pressure and cardiac contractility via beta1 receptors; neonatal tachycardia also occurs.
• Bronchospasm is a potential hypersensitivity response to beta adrenoreceptor agonists.
• Depletion of white cells after several weeks’ administration is a potential hypersensitivity response to beta adrenoreceptor agonists.
• Liver enzyme elevations/abnormalities are potential hypersensitivity responses to beta adrenoreceptor agonists.
• Hyperglycemia may stimulate over-production of fetal insulin, resulting in neonatal hypoglycemia.
• Anaphylaxis is a potential hypersensitivity response to beta adrenoreceptor agonists.
• Hypocalcemia in the neonate has been reported.
• Rash in 3-4 per cent of recipients is a potential hypersensitivity response to beta adrenoreceptor agonists.
• Renin-Angiotensin System: Pulmonary edema, secondary to acute fluid retention, which may or may not be accompanied by bloating.
• Central Nervous System: Tremor, tension, headache, anxiety, nervousness, insomnia, irritability, emotional lability, dizziness, hallucinations and even paranoia.
• Smooth Muscle of Many Organs: Inhibition of the smooth muscle of the GI tract/gut may cause gastric stasis, leading to loss of appetite, nausea and vomiting.
• Mucus-Secreting Glands: Dry mouth, which requires frequent water rinses; drying of lung secretions, which may lead to chest infections.
• Metabolic Processes: Hyperglycemia.
• If the woman is diabetic, there is an appreciable risk of keto-acidosis and subsequent fetal loss.
• Thromboembolic disorders involve overproduction of clots which result in decreased blood flow and total vessel occlusion.
• Control of convulsions may involve either magnesium sulphate or diazepam.
• Manifestations of thromboembolic disorders include hypoxia, anoxia, and even necrosis.
• These disorders are treated by drugs that interfere with normal coagulation process to prevent formation of clots.
• Hemorrhagic disorders are characterized by excessive bleeding.
• These disorders are treated by drugs that promote the clotting process.
• Some conditions that cause hemorrhagic disorders include Hemophilia, which is characterized by genetic lack of clotting factors, Liver disease, which is characterized by non-production of proteins and clotting factors necessary for clot formation, and Bone marrow disorders, which are characterized by insufficient quantity of platelets rendering them ineffective.
• Antiplatelet agents exert their action by decreasing the responsiveness of platelets to stimuli that cause it to clump or aggregate, thereby decreasing the formation of platelet plug.
• Therapeutic action of antiplatelet agents is achieved by blocking receptor sites on the platelet membrane, preventing platelet adhesion and aggregation, and preventing platelet-platelet interaction as well as interaction of platelets to clotting chemicals.
• Antiplatelet agents are primarily indicated for cardiovascular diseases that have potential for development of vessel occlusion, maintenance of arterial and venous grafts, preventing cerebrovascular occlusion, and as an adjunct to thrombolytic therapy for treatment of myocardial infarction.
• One drug in this class, Anagrelide, blocks the production of platelets in the bone marrow.
• Only heparin and warfarin are indicated for children but these drugs alone require careful dose calculation.
• Caution is particularly important to prevent injury when using antiplatelet agents in adults, and it is important that adults are educated on what to do should bleeding occurs as well as what signs of bleeding should be watched out for.
• Other drugs taken should be documented because there are a lot of drug interactions with these drug class.
• Pregnancy renders the mother’s cerebral circulation vulnerable to any hypertensive episode, while, simultaneously, the uterine and placental circulations are unable to autoregulate (adjust) to compensate for hypotension and the associated reduced perfusion pressure.
• High blood pressure (hypertension) complicates about 10 percent of all pregnancies.
• In pregnancy, diastolic BP should normally be below: 75mmHg in the second trimester; 85mmHg in the third trimester.
• There are several different types of high blood pressure during pregnancy, which vary in severity and impact on the body.