Some drugs are dangerous throughout all months of pregnancy. The table below lists drugs which definitely should not be given during pregnancy and those which are best to avoid if possible.

Drugs to be Avoided or Used with Caution During Pregnancy

Drug	Avoid	Caution	Comments
Antibiotics
Chloramphenicol		3	Avoid using long courses. Causes 'grey' baby syndrome.
Co-trimoxazole		3	Can cause abnormalities and blood disorders in the baby.
Gentamicin		1,2,3	Only use if really necessary
Griseofulvin	1,2,3		Use topical drugs if really necessary
Metronidazole	1	2,3	Use lower doses (see following page for more details)
Nitrofurantoin		3	May affect the baby's blood if used near to delivery
Streptomycin	1,2,3		Can damage hearing of the baby. Note: treatment for TB should not be interrupted or postponed during pregnancy. Refer to your national TB guidelines for drugs of choice in pregnancy. If isoniazid is used, pyridoxine should also be given to prevent peripheral neuropathy.
Tetracyclines	1,2,3		This includes doxycycline.
Anti-malarials
Halofantrine (Halfan)	1,2,3
Mefloquine (Lariam)	1	2,3	Only use if no other drug is available.
Pyrimethamine/ Sulfadoxine (Fanisdar)		1,2,3	If possible use quinine instead
Quinine			This benefit outweighs the risk. Preventive measures are very important such as sleeping under a net and taking prophylaxis, e.g. chloroquine each week.
Antihelmintics
Albendazole	1,2,3		Known to cause abnormalities in animal studies.
Mebendazole	1	2,3	Consider using piperazine if appropriate
Praziquantel		1,2,3	If possible wait until after delivery
Thiabendazole	1,2,3		Although thiabendazole is no longer on the WHO essential drug list, it may still be widely used.
Analgesics
Aspirin & other	3	1,2	Use paracetamol
NSAID
Anti-epileptics
Carbamazepine		1,2,3	Benefit outweighs the risk.
Phenobarbitone		1,2,3	If possible use only one
Phenytoin		1,2,3	Use drug and monitor blood levels.
Miscellaneous
All cancer drugs	1,2,3		Seek specialist help.
Aminophylline/theophylline		3	May cause irritability in the baby if used near delivery.
Benzodiazepines e.g. diazepam		1,2,3	Avoid regular and prolonged use
Iodine	1,2,3		High doses can cause goitres in the baby.
Vitamin A (Retinol)	1		Large doses may cause abnormalities in the 1st trimester.

1 = first trimester (1-3 months)    
2 = second trimester (4-6 months)
3 = third trimester (7-9 months)
AVOID = do not use at all
CAUTION = only use if the benefit outweighs the risk.
If the drug is not listed above it does not mean it is safe to use in pregnancy.
Please check other literature for more information.
Source : Practical Pharmacy, April-June, 1998, Issue 9

Breast feeding

Most drugs can pass from the mother's blood stream into the mother's milk just like the way they pass from the mother's blood stream into the baby's blood steam. A baby who is being breast fed will thus receive small amounts of drugs that the mother is receiving.

There are certain drugs which do not pass into the mother's milk at all because of their chemical nature and there are others which do pass into the breast milk but in amounts too small to produce any harmful effects on the baby. However, there are certain drugs which produce unwanted effects on the breast fed baby for reduced milk production in the mother. It is always advisable for the mother to consult the doctor before taking any drug, while breast feeding the baby. One must try as far as possible to avoid drugs rather than avoiding breast feeding. When the mother is suffering from chronic conditions, and has to regularly take drugs, and the doctor decides, if she can continue breast feeding or not. In case she is allowed to continue to breast feed her baby, the baby should be closely monitored (observed) by the doctor for any possible harmful effects. It is important to remember that besides very few chronic conditions a mother is never advised to refrain from breast feeding.

Weighing the risks versus benefits in the use of drugs

Source: Practical Pharmacy

Advice on breast feeding varies as the drugs vary and is discussed in this column whenever necessary.

Drugs to be Avoided OR Used with Caution During Breast Feeding

Drug	Avoid	Caution	Comments
Chloramphenicol		X	Only use if no other antibiotic is suitable.
Ciprofloxacin	X
Co-trimoxazole		X	Especially if the baby has jaundice.
Metronidazole		X	Avoid large single doses e.g. 2g daily.
Tetracyclines	X		This includes doxycycline.
Others
Aspirin	X		Use paracetamol instead.
Benzodiazepines e.g. diazepam		X	Avoid repeated doses. May cause weight loss and tiredness in the baby.
Carbimazole	X		May affect the baby's thyroid function.
Cimetidine		X	A significant amount is found in breast milk - not known to be harmful but advisable to avoid using.
Ephedrine		X	May cause irritability and disturbed sleep patterns in the baby.
Iodine (includes cough mixtures with iodine)	X		It appears that iodine is concentrated in breast milk and can severely affect the thyroid gland of the baby. If absolutely necessary to treat the mother then advise to stop breast feeding.
Oestrogens (in oral contraceptives)	X		Reduces the milk supply. Choose an oral contraceptive that contains progesterone only.
Phenobarbitone		X	May cause drowsiness and inhibit the baby's suckling reflex.
Thiazide diuretics e.g. bendrofluazide		X	Large doses may reduce milk supply.

If a drug is not listed in the table it does not mean that it is definitely safe to use. Please check other literature for more details.

Reproduced with thanks from: Practical Pharmacy, April-June 1998, Issue 9.