Drugs and their categories in pregnancy and breastfeeding-I

Drug	Pregnancy category	Compatibility with breastfeeding
ibuprofen	C	compatible [Note 10]
ichthammol	unlisted	compatible
idoxuridine	topical use: B1	topical use: caution, insufficient data
iloprost	B3	caution, insufficient data
imipenem+cilastatin	B3	compatible
imipramine	C [Note 6]	compatible
imiquimod	B1	avoid, insufficient data
immunoglobulin, normal	unlisted	compatible
indapamide	C	avoid, insufficient data
indinavir	B3	insufficient data [Note 1]
indomethacin	C	compatible [Note 10]
infliximab	C	compatible
insulin	unlisted	compatible
interferon alfa	B3	caution, insufficient data but low transfer anticipated
interferon beta-1a	D	caution, insufficient data
interferon beta-1b	D	caution, insufficient data
interferon gamma	B3	avoid, insufficient data
ipratropium bromide	B1	compatible
irbesartan	D	avoid, insufficient data
iron preparations	A	compatible
isoniazid	A	caution, monitor infant for hepatitis, vision changes; observe for fatigue, weakness, malaise, anorexia, nausea, vomiting
isoprenaline	A	caution, insufficient data
isosorbide dinitrate	B1	avoid, insufficient data
isosorbide mononitrate	B2	avoid
isotretinoin	systemic use: X topical use: D	systemic use: avoid topical use: avoid
ispaghula	unlisted	compatible
itraconazole	B3	caution, insufficient data
ivermectin	B3	compatible

Note 1: In Australia, breastfeeding is not recommended for HIV-positive women because of the possibility of HIV transmission. Note 2: Human data are inadequate and the safety of these medications in pregnancy is uncertain. Note 3: Antiandrogens have the potential to feminise the male fetus, avoid in pregnancy. Note 4: Tetracyclines are safe for use during the first 18 weeks of pregnancy (16 weeks postconception) after which they may affect the formation of the baby's teeth and cause discolouration. Note 6: Tricyclic antidepressants have been taken by a large number of pregnant women without any proven increase in the frequency of fetal malformation. In full-term neonates, reversible adverse effects have occasionally been observed, but very rarely cause significant problems. Note 7: Although theophylline has a Category A rating, it does cross the placental barrier. The effect on fetal development is not known. Theophylline clearance is significantly decreased in premature infants. Therefore, if this drug is administered to the mother near the time of delivery, the neonate should be monitored closely for the pharmacological effects of theophylline. Hence the use of theophylline in pregnant women should be balanced against the risk of uncontrolled asthma. Note 8: See also: Cleland LG, James MJ, Proudman SM. Fish oil: what the prescriber needs to know. Arthritis Research and Therapy 2006;8(1):202-11. Note 9: See leflunomide regarding preconception advice and cholestyramine washout. Note 10: If an NSAID is required in a breastfeeding patient, diclofenac or ibuprofen is preferred. Note 11: Absorption of eye drops into the maternal circulation is generally low, although there are occasional reports of systemic effects. Nevertheless, significant transfer into milk is unlikely. Note 12: Large molecular weight proteins/polypeptides are unlikely to transfer into milk. In the absence of specific information, adverse effects in the infant are unlikely. Note 13: Early reports of pregnancy outcomes in women treated with beta blockers in pregnancy, particularly dealing with propranolol, described a relatively high incidence of fetal growth restriction. This appears to be the basis for the C classification of the class of drugs. Since these findings were not from randomised studies, but were clinical descriptions of women who had underlying disorders known to be associated with an increased rate of both intrauterine fetal growth restriction and death, it is not possible to determine whether the described outcomes were due to the therapy or to the disorder for which therapy was prescribed. Subsequent evidence has indicated fetal growth restriction in hypertensive pregnant women treated with atenolol, but better fetal growth in women treated with another beta blocker, oxprenolol, than in women treated with methyldopa. This has been attributed to the intrinsic sympathomimetic activity inherent in this drug. No other fetal or neonatal problems have been attributed to beta-blocker therapy in pregnancy, and they are widely prescribed for the treatment of hypertension in this situation.