Medicines for Children

TL;DR. Children are not small adults: their absorption, distribution, metabolism, and excretion all differ, and they change month by month through infancy. Doses are calculated by weight, not age, and the age bands on a bottle are a rough approximation. Use the device supplied, never a kitchen spoon: dosing errors with household spoons are a documented and common source of harm. Aspirin is contraindicated under 16, codeine under 12, and cough and cold medicines under 6. And the single largest cause of serious paediatric poisoning is the grandparent's handbag.

1. Why children are different

A newborn's higher body water means water-soluble drugs are diluted more. Immature liver enzymes mean drugs cleared by the liver accumulate: this is why chloramphenicol caused "grey baby syndrome" in the 1950s, a fatal circulatory collapse from accumulation because neonates cannot glucuronidate it.

Thin skin and high surface area mean topical medicines are absorbed far more in babies. Potent topical steroids, and even excessive salicylate or antiseptic application, can produce systemic effects.

Children clear many drugs faster per kilogram than adults, which is counterintuitive and is why paediatric doses per kg are often higher.

2. Dosing: the practical rules

Dose by weight, not by age. The age bands on a bottle assume an average-sized child. A small six-year-old and a large six-year-old can differ by 50 percent in weight.

Common paediatric doses (illustrative; follow your product and your clinician):

Concentrations differ and this causes errors. Paracetamol suspension comes as 120 mg/5 mL (infant) and 250 mg/5 mL (six-plus). Giving the volume appropriate for one strength using the other bottle produces a twofold error. Read the concentration every time, especially when switching bottles or when a different adult is dosing.

Use the supplied syringe or measuring device. Studies consistently find that kitchen teaspoons vary from roughly 2 to 9 mL, and that dosing errors with household spoons and cups are common. Oral syringes are more accurate than cups, particularly for small volumes.

Write it down. A shared record of what was given and when prevents the commonest household overdose scenario: two carers each giving a dose.

3. What not to give children

Chloramphenicol eye drops are widely sold and used in children; note they are not licensed for under-2s in some markets without advice.

4. Fever in children

Fever is a functional immune response, not the disease. Current guidance (NICE and equivalents) is clear:

• Treat for the child's comfort and distress, not to normalise the number.
• Antipyretics do not prevent febrile convulsions. This is the single most common misunderstanding, and it drives a great deal of unnecessary medicating and parental anxiety.
• Do not alternate paracetamol and ibuprofen routinely. It produces marginally better temperature control and substantially increases dosing errors. Use one properly; consider the other only if the first is insufficient and the child is distressed.
• Do not tepid-sponge, do not undress or overdress, and encourage fluids.

The "traffic light" red flags requiring urgent assessment:

• Under 3 months with a temperature of 38 °C or above (this is an emergency; babies this young need assessment regardless of how well they look)
• 3 to 6 months with a temperature of 39 °C or above
• A non-blanching rash (does not fade when pressed with a glass)
• Neck stiffness, bulging fontanelle, photophobia, seizure
• Difficulty breathing, grunting, chest recession, rapid breathing
• Very drowsy, difficult to rouse, or a weak, high-pitched, continuous cry
• Mottled, blue, or ashen skin
• Reduced wet nappies or other signs of dehydration
• Fever lasting more than 5 days
• Parental instinct that something is seriously wrong. This is a legitimate clinical signal and should be acted on.

5. Giving medicine to a child who does not want it

Practical, and mostly untaught:

• Oral syringe into the side of the cheek, slowly, in small amounts. Squirting to the back of the throat triggers gagging and coughing.
• Do not pinch the nose or tilt the head back; both increase choking risk.
• Cold and numb: a few minutes on an ice lolly beforehand blunts taste.
• Chase it with a favoured drink or food immediately after.
• Mixing with food or drink is often acceptable and sometimes not: check with a pharmacist, because some drugs are inactivated by dairy or by acid, some must be taken on an empty stomach, and a partly finished yoghurt means a partly taken dose.
• Do not call it sweets. This matters: children who think medicine is a treat are more likely to help themselves later.
• Ask for a different formulation. Many drugs come as liquids, melts, chewables, granules, or suppositories. If a child cannot manage one, another usually exists.
• Praise, do not punish. Struggling with medicine is normal.

6. Poisoning: the biggest paediatric medicine risk

Household medicines are the leading cause of poisoning in young children, and the pattern is consistent enough to plan around.

The commonest scenarios:

• A visitor's handbag or coat pocket left on the floor. Grandparents' medicines are the classic case, because they carry multiple drugs and are unused to childproofing.
• Medicines left on a bedside table or kitchen counter.
• Iron tablets and vitamin gummies, which look exactly like sweets. Iron is a leading cause of fatal childhood poisoning (Chapter 16), and melatonin gummy poisonings have risen sharply.
• Blister packs, which are not childproof.
• Liquid nicotine and e-liquid, which is highly concentrated and rapidly toxic (Chapter 89).
• Button batteries, which are not medicines and belong here anyway: a swallowed button battery can burn through the oesophagus within two hours and kill. This is a genuine emergency requiring immediate hospital assessment, not observation.

What to do if a child may have swallowed something:

1. Call emergency services or your poisons centre immediately.
2. Do NOT make them vomit. This is old advice and it causes harm.
3. Take the packet with you.
4. Do not wait for symptoms. Paracetamol in particular produces none for a day (Chapter 65), and by the time symptoms appear the antidote window has largely closed.

Prevention: locked or high cupboards, child-resistant closures (which are resistant, not proof: a determined three-year-old often manages them), never leaving doses out ready, warning visitors about bags, and returning unused medicines to a pharmacy (Chapter 86).

7. Antibiotics and children

Most childhood infections are viral (Chapter 72):

• Ear infections: most resolve without antibiotics; delayed prescribing is standard in many guidelines.
• Sore throat: mostly viral.
• Cough and bronchiolitis: viral. Bronchiolitis in infants is treated supportively; salbutamol does not help it, despite frequently being tried.
• Croup: a single dose of oral dexamethasone is highly effective and is the treatment.

When antibiotics are given, complete the prescribed course and ask before stopping early.

8. Off-label use, and why it is normal

A large proportion of medicines given to children are used off-label or unlicensed, meaning outside the terms of the marketing authorisation, often because trials were never done in children. Historically children were excluded from trials for ethical reasons, which produced the paradox that they were treated with less evidence rather than more.

Regulatory changes (the EU Paediatric Regulation, the US Best Pharmaceuticals for Children Act) now require paediatric investigation plans for new drugs. Off-label prescribing in children is nonetheless routine, legal, and often the best available option; it is a reason to ask questions, not a reason for alarm.

9. Vaccination

Covered fully in Chapter 74. The practical points for parents:

• Keep to the schedule. Timing is designed around when maternal antibodies wane and when disease risk peaks.
• Paracetamol afterwards is fine for discomfort; routine prophylactic paracetamol before vaccination is generally not advised, because it may slightly blunt the antibody response.
• Mild fever and irritability for a day or two are expected.
• Catch-up schedules exist if doses are missed.

10. The bottom line

• Children are not small adults. Dose by weight, and check the concentration on the bottle every time, because paediatric suspensions come in more than one strength.
• Use the supplied syringe. Kitchen spoons vary by a factor of four, and dosing errors are common.
• Aspirin under 16, codeine under 12, cough and cold medicines under 6, honey under 12 months. These are hard rules with bodies behind them.
• Treat fever for comfort, not for the number, and antipyretics do not prevent febrile convulsions. Learn the red flags, and trust parental instinct as a genuine warning sign.
• A visitor's handbag on the floor is the classic poisoning scenario. Iron tablets and gummy vitamins look like sweets, and button batteries are an immediate emergency.
• If a child may have swallowed something: call for help now, do not induce vomiting, take the packet, and do not wait for symptoms.

Sources and notes

Doses, cautions, and interactions follow the British National Formulary and the electronic Medicines Compendium; US figures follow FDA labelling. Paediatric pharmacokinetic differences by developmental stage follow the BNF for Children and standard paediatric pharmacology texts. Grey baby syndrome from chloramphenicol follows the 1950s case literature and is the classic illustration of immature glucuronidation. Weight-based dosing and the inadequacy of age bands follow BNFC guidance. Dosing errors with household spoons and cups follow Yin et al., Pediatrics, 2010 and 2016, which found oral syringes substantially more accurate. Age restrictions follow: aspirin and Reye's syndrome (CDC surveillance and Belay et al., NEJM, 1999); codeine and tramadol (EMA and FDA restrictions following CYP2D6-related deaths); cough and cold medicines under 6 (MHRA 2009 review and FDA advisories); honey and infant botulism (CDC); promethazine under 2 (FDA boxed warning). Fever management, the failure of antipyretics to prevent febrile convulsions, and the traffic-light red flags follow NICE guideline NG143 and CG160. Alternating antipyretics evidence follows Wong et al.'s Cochrane review. Paediatric poisoning epidemiology, including the visitor's-handbag pattern and iron as a leading cause of fatal ingestion, follows national poisons centre reporting. Button battery injury timelines and management follow NHS, RCEM, and the National Capital Poison Center guidance. Off-label paediatric prescribing prevalence follows Conroy et al., BMJ, 2000, and the subsequent EU Paediatric Regulation and US BPCA.

Open questions. A large share of medicines given to children remain unlicensed for that use, so paediatric dosing often rests on extrapolation rather than trial data. How much of paediatric fever treatment is for the child's benefit rather than the parent's anxiety is not measurable.

👉 Next: medicines in pregnancy and older age.