DRUG THERAPY DURING PREGNANCY

Developed By

D. Ann Currie , R.N.,M.S.N.

• PHYSIOLOGICAL CHANGES DURING PREGNANCY AND THEIR IMPACT ON DRUG THERAPY

• EVERY SYSTEM IN THE BODY IS EFFECTED BY PREGNANCY

• PHARMACOKENETICS OF DRUGS IS EFFECTED BY PREGNANCY

PHARMACOKENETICS OF DRUGS DURING PREGNANCY

• ABSORPTION- DECREASED GI MOTILITY CAUSES INCREASED DRUG ABSORPTION.

• DISTURBUTION- PROTIEN BINDING IS DECREASED CAUSES INCREASED FREE DRUG TO BE AVAILABLE.

• METABOLISM-INCREASED HEPATIC METABOLISM OCCURS FOR SOME DRUGS

PHARMACOKENETICS

• EXCRETION- IN THE 3RD TRIMESTER INCREASED RENAL BLOOD FLOW & GFR CAUSES SOME DRUGS TO CLEAR THE BODY FASTER.

DRUG THERAPY IN THE CHILDBEARING CLIENT

REQUIRES SPECIAL CONSIDERATIONS

IS CHALLENGING TO PROVIDE EFFECTIVE TX WHILE AVOIDING HARM TO EMBRYO,FETUS OR NEONATE

CENTERED ON RISK/BENEFIT RATIO

EFFECTS OF DRUGS NOT ALWAYS KNOWN

ANY DRUG TAKEN BY THE PREGNANT OR BREASTFEEDING CLIENT HAS THE POTENTIAL TO REACH THE FETUS BY WAY OF MATERNAL CIRCULATION OR

NEONATE BY WAY OF BREASTMILK

EFFECTS OF DRUGS ON THE EMBRYO, FETUS, OR NEONATE

• NO EFFECT.• LITTLE• SERIOUS- FETAL TOXICITY• SPONTANEOUS ABORTION• DEATH• FETAL MALFUNCTION• FETAL MALFORMATIONS.

DRUG THERAPY DURING PREGNACY

• CENTERED ON RISK/BENEFIT RATIO• EFFECTS OF SOME MEDICATION ARE KNOWN• UNKNOWN- NEW MEDICATIONS,

DIFFERENT COMBINATIONS, DEFICIENCY IN MATERNAL METABOLISM

• NO DRUG IS ABSOLUTELY SAFE.

RECENT STUDIES

• 75% OF PREGNANT CLIENTS USE 3-10 DIFFERENT DRUGS(PRESCRIPTION OR OTC’S) OTHER THAN VITAMINS/MINERAL SUPPLEMENTS DURING THEIR PREGNANCY.

• OTC’S WERE USED 4 TIMES THAT OF PRESCRIPTION DRUGS.

TYPES OF DRUGS USED IN THE STUDY BY PREGNANT CLIENTS

• DIETARY SUPPLEMENTS

• ANTIEMETICS• ANTACIDS• TRANQUILIZERS• HYPNOTICS• ANTIBIOBIOTICS• ANTIHISTAMINES

• ANALGESICS• DIURETICS• ETOH• CNS DEPRESSANTS• CNS STIMULANTS

DRUG LEVELS IN THE FETUS REACHED 50-100% OF THE MATERNAL BLOOD LEVELS

SELF TREATMENT WITH DRUGS DURING PREGNANCY

• SELF TX OF MINOR ILLNESSES OR DISCOMFORTS SHOULD BE DISCOURAGED

• *SELFTREATMENT OF ANY ILLNESSES SHOULD BE DISCOURAGED

• WOMEN SHOULD BE INSTRUCTED TO KEEP A COMPLETE RECORD OF ALL MEDICATIONS TAKEN .

THE CHALLENGE OF PROVIDING EFFECTIVE CARE/TX FOR THE

CHILDBEARING CLIENT

• AVOID HARM TO EMBRYO, FETUS, NEONATE.

• DILEMMA UNFORTUNATELY THE RISK OF MOST DRUGS HAVE NOT BEEN ESTABLISHED.

• DESPITE NOT KNOWING DRUG THERAPY DURING PREGNANCY

• CANNOT OR SHOULD NOT BE AVOIDED BECAUSE THE HEALTH OF THE FETUS DEPENDS ON THE HEALTH OF THE MOTHER.

• FOR EXAMPLE: SEIZURES ,DM, MG, SLE,OR INFECTIONS.

BIRTH DEFECTS

• INCIDENCE OF MAJOR STRUCTURAL DEFECTS(ABNORMALITIES) IS ABOUT 6% OF ALL PREGNANCIES.

• 3% ARE CAUSED BY DRUGS OR ENVIRONMENTAL FACTORS/EXPOSURE

• 3% HAVE A UNKNOWN CAUSES

BIRTH DEFECTS

• 1/2 OF THE BIRTH DEFECTS ARE OBVIOUS AT BIRTH.

• 1/2 OF THE BIRTH DEFECTS AREN’T DISCOVERED UNTIL LATER IN LIFE OR DISCOVERED DURING AN AUTOPSY

• INCIDENCE OF MINOR STRUCTURAL ABNORMALIES IS NOT KNOWN.

BIRTH DEFECTS

• INCIDENCE OF FUNCTIONAL ABNORMALITIES IS NOT KNOWN-GROWTH RESTRICTIONS, MENTAL RETARDATION, AND LEARNING DISABLITIES

• SOME ABNORMALITIES HAVE MULTIPLE CAUSES-GENETIC FACTORS, ENVIRONMENTAL FACTORS, CHEMICALS OR DRUGS.

TERATOGENICTERATOGENESIS

• TERAS-”MONSTER”• GENSIS-”PRODUCING”• BIRTH DEFECTS/DISTORTION OF GROSS

ANATOMY.• EXAMPLES- CLEFT LIP/PALATE, CLUBFOOT,

NEURAL TUBAL DEFECTS, MISSING OR MALFORMED LIMBS/FINGERS.

TERATOGENIC

• ALSO-BEHAVORIAL AND/ OR BIOCHEMICAL ABNORMALITIES.

• TERATOGENESIS MAYBE DIRECT-IE-MALFORMATIONS OF STRUCTURES

• OR INDIRECT-SUCH AS INTERFERING WITH O2 OR NUTRIENTS.

TERATOGENIC

• EXAMPLE OF KNOWN TERATOGENIC AGENTS:• ONE TIME EXPOSURE IS THALIDOMIDE-

CAUSES MISSING LIMBS.• CONT. OR PROLONG EXPOSURE IS ETOH-

CAUSES FAS.• SEE HANDOUT FOR OTHER AGENTS.

FETAL EFFECTS FROM DRUGS DEPEND ON SEVERAL FACTORS

• TIME- WHEN DRUG IS TAKEN IN PREGNANCY.

• PREIMPLANTATION/PRESOMITE PERIOD-CONCEPTION TO 2 WEEK

• HIGH DOSE- MAYBE LETHAL/DEATH/ABORTIONS.

• LOW DOSE-MAYBE NOTHING.

• EMBRYONIC PERIOD-3-8 WEEKS *FIRST TRIMESTER*

• GROSS MALFORMATIONS• FETAL PERIOD-9-40 WEEKS(TERM)• FUNCTION PROBLEMS RATHER THAN

GROSS ANATOMY- *LEARNING DEFICITS &/OR BEHAVORIAL ABNORMALIES

WHY IS IDENTIFICATION OF TERATOGENIC AGENTS

SOMETIMES DIFFICULT TO IDENTIFY?

INCIDENCE OF CONGENITAL ANOMALIES IS GENERALLY LOW.

ANIMAL TESTS MAY NOT BE RELIABLE PROLONGED OR INCREASED EXPOSURE

MAYBE REQUIRED. EFFECTS MAYBE DELAYED OR NOT

RECONIZED. BEHAVIORAL EFFECTS ARE DIFFICULT TO

DOCUMENT. CONTOLLED EXPERIMENTS CANNOT BE

DONE ON HUMANS.

DOCUMENTATION IS INCOMPLETE ONLY IN A LIMITED NUMBER OF DRUGS IS

THE TERATOGENIC EFFECTS KNOWN OR PROVEN.

LACK OF PROOF OF TERATOGENICITY DOES NOT MEAN A DRUG IS SAFE IN PREGNANCY

MAY MEAN THERE IS A LACK OF RESEARCH OR INFORMATION.

PROVING A DRUG IS A TERATOGEN

• 3 CITERIA MUST BR MET:• 1. DRUG MUST CAUSE A CHARACTERISTIC SET

OF MALFORMATIONS.• 2. IT MUST ACT ONLY DURNIG A SPECIFIC

WINDOW OF VULNERABILITY-3-8 WEEKS OF GESTATION

• 3.THE INCIDENCE OF MALFORMATIONS SHOULD INCREASE WITH INCREASED DOSAGE & DURATION OF EXPOSURE.

PLACENTAL DRUG TRANSFER

• THE PLACENTA IS NOT A COMPLETE BARRIER.• SOME DRUGS ARE STOPPED.• SOME DRUGS(IN FACT MOST) ARE NOT.• WAYS DRUGS ARE TRANSFER ACROSS- SIMPLE

DIFFUSION-ACTIVE TRANSPORT.

TRANSFER DEPENDS ON SEVERAL FACTORS

• CHEMICAL PROPERTY OF THE DRUG• MOLECULAR WEIGHT.• PROTEIN BINDING CAPABILITIES.• CHEMICAL CONFIQURATION.• LIPID SOLUBILITY.*• PERIOD OF TIME DRUG REMAINS IN

MATERNAL BLOODSTREAM• HALFLIFE OF THE DRUG.

TRANSFER DEPENDS ON SEVERAL FACTORS

• CONT.• AMOUNT OF THE DRUG.• PATHOLOGICAL PROCESSES OF THE

PLACENTA.• WHEN IN THE PREGNANCY-INCREASED BLOOD

FLOW TO THE PLACENTA IN LAST PART OF PREGNANCY.

MOST DRUGS TRANSFER AND ARE AT 50-100% THAT OF THE

MATERNAL LEVELS * SOME DRUG LEVELS ARE MORE THAN THE

MATERNAL LEVELS

• DRUGS THAT TRANSFER EASILY ARE LIPID SOLUBLE.

• DRUGS THAT ARE DIFFICULT/HARD TO TRANSFER ARE IONIZED DRUGS-HIGHLY POLAR-OR PROTEIN BOUND.

HOW IS DATA COLLECTED ON DRUGS WHICH CAUSE PROBLEMS

IN PREGNANCIES?

• NO HUMAN EXPERIMENTATION• SYSTEMATIC COLLECTION AND ANALYZING

OF DATA ON DRUGS TAKEN BY PREGNANT CLIENTS.

• REPORTING OF INFORMATION BY HEALTH PROFESSIONALS.

• SEE FORM.

THE NURSE’S ROLE AND RESPONSIBILITY IN DRUG THERAPY

IN THE CHILDBEARING CLIENT

• KNOWLEDGE (CURRENT &ACCURATE INFORMATION)-

• PREGNANCY• MEDICAL CONDITIONS• MEDICAL TREATMENTS• DRUGS AND CLIENT

EDUCATION OF PREGNANT/PREPREGNANT CLIENTS

• PROVIDE ACCURATE INFORMATION WITH RATIONALES

• INFORMATION SOULD BE CURRENT AND BASED ON EVIDENCE.

• * ESTABLISH ENVIRONMENT CONDUCIVE TO EXCHANCE OF INFORMATION*- TRUST.

• POTENTIAL HARM/RISKS.

EDUCATION

• BENEFITS• COMMON SUBSTANCES & OTC DRUGS TO

AVOID IN PREGNANCY- ASA,ETOH,INCREASED DOSES OF MULTVITAMINS,CAFFIENE,CIGARETTE SMOKING,ETC.

• AVOID SELF TX-OTC’S, DRUGS FORM MEXICO.

• ADVOCATE FOR CLIENTS AND GENERAL PUBLIC.

• * SUPPORT*• ASSIST WITH COPING IF CLIENT HAS TAKEN

A TERATOGENIC AGENT..WITH GUILT OR FEAR…ASSOCIATED WITH DRUGS TAKEN IN PREGNANCY.

PREGNANT CLIENT’S BILL OF RIGHTS

“RIGHT TO KNOW”

For individual drugs see handout.