Pharmacology: Pregnancy and Lactation

Pregnancy and Drug Use

• Pregnancy includes important phases: Labor and Delivery.
• Drug potency refers to the strength of a medication's effect; high potency signifies safer drugs, while low potency indicates a greater risk.
• Risks associated with drug use in pregnant women must consider maternal disease, necessary dose adjustments, and potential impacts during lactation.

Lactation Considerations

• Nursing mothers must consider the effects of medications on breast-fed infants and milk production.

Reproductive Potential

• Medications can impact fertility and increase the risk of pregnancy loss in both females and males.

Drug Responsiveness

• Variability in drug responsiveness can result from genetic factors, leading to idiosyncratic reactions.
• Hypersensitivity refers to exaggerated allergic responses.
• Tolerance develops when patients no longer experience the same drug effect as originally felt.
• Placebo effect occurs when patients feel relief without actual drug action, influenced by their beliefs about the treatment.

Thai FDA Medicines Classification

• Modern Drugs: Require licensing; includes household remedies like antacids.
• Traditional Drugs: Controlled less strictly; common examples include herbal remedies.
• Drug Classifications:
  • P2: High-risk psychoactive substances (e.g., Ketamine).
  • P3: Lower risk psychoactive substances (e.g., Pentazocine).
  • P4: Even lower risk (e.g., Lorazepam).
  • N2: Narcotic drugs, such as morphine.

Rational Drug Use (RdU)

• Focuses on providing patients with appropriate medications that meet individual needs while minimizing cost and avoiding adverse effects.
• Key components include ensuring medication is medically indicated, assessing efficacy, and managing potential adverse drug reactions (ADRs).

Cardiovascular Drugs

• Norepinephrine:
  • Low doses increase heart rate via beta-1 receptors.
  • High doses cause vasoconstriction, boosting total peripheral resistance (TPR) and blood pressure.
  • ADRs include cardiac arrhythmias and bradycardia.
• Dopamine:
  • Low doses induce vasodilation; intermediate doses increase heart rate; high doses cause vasoconstriction.
  • Therapeutic use includes shock management.

Respiratory Drugs

• Antihistamines (H1): Used for allergic inflammation, block histamine effects.
• Expectorants: Loosen mucus; common examples include Guaifenesin which reduces surface tension of fluids.
• Decongestants: Alpha-adrenergic agonists dilate blood vessels in the nasal area.

Antineoplastic and Immunosuppressant Drugs

• Antineoplastic drugs primarily target cancer, with side effects including bone marrow suppression.
• Immunosuppressants (e.g., corticosteroids) are used to prevent organ transplant rejection and treat autoimmune disorders; they can increase the rate of infections and exacerbate other conditions such as osteoporosis.

Nursing Considerations

• Monitor patients for potential drug reactions and manage interventions to mitigate risks, such as observing for changes in liver function or signs of adverse reactions.
• Educate patients on avoiding specific medications under certain conditions (e.g., patients with kidney disease should avoid magnesium-based laxatives).

General Guidelines

• Antimuscarnic drugs reduce gastric acid production and muscle spasms, but can cause side effects like tachycardia and dry mouth.
• Avoid using laxatives regularly to manage constipation; instead, focus on integrating fiber-rich fruits like bananas and papayas into the diet.