What, When, and How Much — A Practical Guide to Medicating Children

Lead

Late at night, facing the medicine cabinet when a child has a fever, the questions stack up.

"The weight changed — should I recalculate the dose?" "Does syrup absorb differently than powder?" "Is it okay to use the steroid cream every day?" "Does the inhaler still work if they're crying?" These are real operational questions that come with managing a sick child, and the explanation given at the pharmacy often doesn't stick past the moment you're out the door.

This guide walks through the medications most commonly used in children, organized by category: how to think about dosing, what the different formulations mean, and answers to the questions that come up most often. Any prescribing, starting, or changing of medication still requires a physician or pharmacist — this is a framework for understanding, not a substitute.

Fever and Pain Medications

Acetaminophen — the Recommended First Choice

Acetaminophen (paracetamol) is the first-line medication for fever and pain management in children, recommended by both the American Academy of Pediatrics (AAP) and the Japan Pediatric Society [1,4].

Dosing: 10–15 mg per kg of body weight per dose. Maximum four doses per day, spaced at least four hours apart. The 24-hour ceiling is 60 mg/kg/day [1].

Many over-the-counter fever products have different concentrations (for example, 20% vs. 50% powder formulations contain 2.5 times as much active ingredient per gram). When a child grows, it is worth recalculating the mg/kg basis. Writing the number on a sticky note on the medicine cabinet cuts down on late-night confusion.

Formulation choice: Powder, syrup, and suppository all contain the same active compound, but absorption speed differs. Suppositories peak around 30–60 minutes after insertion and are useful when vomiting prevents oral dosing. Syrups are often chosen for ease of administration, but check the expiration date after opening.

Ibuprofen — From Six Months of Age

Ibuprofen can be used in children six months of age and older [1]. The dose is 5–10 mg/kg per dose.

In a large practitioner-based RCT of about 84,000 febrile children, Lesko and Mitchell (1995) found that short-term ibuprofen did not increase the risk of hospitalization for gastrointestinal bleeding, kidney failure, or anaphylaxis compared with acetaminophen [2] (the trial did not assess prolonged use or milder side effects). Ibuprofen does have a somewhat stronger effect on the gastric mucosa and is best avoided in dehydrated children or those with impaired renal function.

A systematic review by Purssell (2011) examined alternating and combined use of the two drugs. It concluded that any added benefit of combining them is clinically marginal and there is little reason to layer drugs for a symptom one drug can handle. Given the added complexity as well, single-agent use is the default [3].

Why Loxoprofen Is Not Used Under 15

Loxoprofen sodium, sold over the counter in Japan, carries a package-insert note that "safety has not been established in preterm infants, neonates, infants, or children," and its use in children under 15 is not recommended.

Historical context: after the association between aspirin and Reye syndrome — an acute encephalopathy and liver injury that can occur when aspirin is used during certain viral illnesses — was documented in the 1970s and 1980s, a broadly cautious posture toward NSAIDs in children has persisted.

Antihistamines

First Generation versus Second Generation

First-generation antihistamines (chlorpheniramine, diphenhydramine, and others) cross the blood-brain barrier and produce sedation and cognitive effects. They may be used short-term in acute urticaria or similar urgent situations, but prolonged or routine use should be avoided.

Second-generation antihistamines (cetirizine, fexofenadine, loratadine, and others) are less sedating and are appropriate for long-term use from preschool age onward. For chronic urticaria and allergic rhinitis requiring regular treatment, second-generation agents are the recommended choice.

Topical Corticosteroids

What "Rank" Means — and Why "Weaker Is Safer" Is Not Quite Right

Topical corticosteroids are classified in Japan by the Japanese Dermatological Association into five potency groups, from strongest (Rank I) to weakest (Rank V).

Many parents worry that daily steroid use will thin the skin. Skin atrophy (thinning) as a side effect is site-, rank-, and duration-dependent; the risk with appropriate short-term use is low [6]. The relevant shift in thinking: using the right rank for the right amount of time outperforms using a weaker rank sparingly and prolonging the course. Less total steroid is often used with the more targeted approach [6].

Proactive therapy means applying a topical corticosteroid twice weekly even during remission, to prevent relapse. A multicenter European trial in adults by Wollenberg et al. (2008) demonstrated that proactive treatment with 0.1% tacrolimus ointment significantly reduced relapse rates after remission [5], and the Japanese guideline includes proactive therapy with topical corticosteroids as well [6].

Antibiotics — Practical Points

Masking the Taste and Taking It as Prescribed

Bitterness is the main reason children refuse antibiotics, particularly amoxicillin–clavulanate and similar combinations. Mixing with chocolate syrup or ice cream works for masking with most antibiotics. Dairy products and yogurt, however, can impair absorption of some agents (tetracyclines in particular), so checking with the pharmacist before mixing is advisable.

Take it as prescribed: Even when symptoms improve, the basic rule is to give the dose and number of days the doctor prescribed, without stopping on your own or saving leftovers [11]. The widely repeated explanation that stopping early breeds resistant bacteria has little direct evidence behind it, and there is an active debate about keeping courses as short as effectively possible [9]. Whether a course can be shortened is the prescriber's call, so if it is on your mind, ask rather than stopping on your own.

Inhalers and Spacers

Why a Spacer Is Essential Under Age 5

MDIs (metered-dose inhalers) prescribed for asthma or bronchiolitis require proper inspiratory timing to deliver drug to the lungs. The 2024 GINA (Global Initiative for Asthma) guidelines state explicitly that MDI use alone is inappropriate for children under 5, and that a spacer (valved holding chamber) is mandatory [7].

A Cochrane review by Cates et al. (2013; 39 trials including 1,897 children) found that for acute asthma, an MDI given through a spacer worked no worse than a nebulizer. In children, the spacer group also spent less time in the emergency department and had smaller rises in pulse rate and less tremor [8]. These trials were run in emergency and inpatient settings, but they show that an MDI with a spacer can deliver treatment no worse than a nebulizer.

Spacer selection is age-dependent. GINA suggests a face-mask type for ages 0–3 and a mouthpiece type for ages 4–5 [7]. On the common question of whether the inhaler works during crying: inspiration does occur during crying, so the inhaler is not entirely ineffective, but calm breathing is preferable whenever possible.

Suppositories and Eye Drops — Practical Details

Spacing Multiple Suppositories

If an acetaminophen suppository and an antiemetic (such as domperidone) suppository are both needed, absorption sites can overlap. Inserting them 30–60 minutes apart is the standard recommendation.

Minimizing Systemic Absorption of Eye Drops

Closing the eye and applying gentle pressure to the lacrimal sac — the inner corner of the eye — for one to two minutes after instillation (nasolacrimal occlusion) reduces drainage of the drug through the nasolacrimal duct and lowers systemic absorption. In adult volunteers, nasolacrimal occlusion or eyelid closure cut the absorption of a glaucoma drop (timolol) into the blood by more than 60% [10]. When multiple eye drops are prescribed, wait at least five minutes between drops.

Putting It Into Practice

1. Calculate the antipyretic dose by body weight (10–15 mg/kg) and update that number as the child grows. For a 10 kg child, one dose is 100–150 mg. At 20 kg, it becomes 200–300 mg. Writing it on the medicine cabinet means one less mental calculation at midnight.

2. Use topical steroids at the right rank for the right duration. Tentatively applying a weak-rank product thin and prolonged often delivers more total steroid than using the indicated rank properly for a shorter course, with slower clearance of the rash.

3. Make sure any child on inhaled medication has a spacer. Children 3 and under need the face-mask type. Without a spacer, much less of the drug tends to reach the lungs.

Keeping a log of when a medication was started, the dose, its effect, and any suspected side effects makes it easier for the doctor to evaluate the course at the next visit. For children on multiple medications, a record also helps the pharmacist check for interactions.

Summary

The underlying reason parents feel uncertain about medicating children is that three dimensions — weight-based dosing, formulation characteristics, and category-specific usage rules — are all in play at once.

Understanding the mg/kg calculation for acetaminophen, the logic behind topical steroid rank and duration, and the necessity of spacers covers the ground where most day-to-day medication questions arise. When doubt remains, the pharmacist is the most accessible and reliable resource.

References

1. Sullivan JE, Farrar HC; American Academy of Pediatrics, Section on Clinical Pharmacology and Therapeutics; Committee on Drugs. Fever and antipyretic use in children. Pediatrics. 2011;127(3):580–587. PMID: 21357332.
2. Lesko SM, Mitchell AA. An assessment of the safety of pediatric ibuprofen. A practitioner-based randomized clinical trial. JAMA. 1995;273(12):929–933. PMID: 7884951.
3. Purssell E. Systematic review of studies comparing combined treatment with paracetamol and ibuprofen, with either drug alone. Arch Dis Child. 2011;96(12):1175–1179. PMID: 21868405.
4. Japan Pediatric Society. アセトアミノフェン製剤の在庫逼迫に伴う、成人患者への解熱鎮痛薬処方時のご配慮のお願い [Request for consideration when prescribing antipyretic analgesics to adult patients during the acetaminophen shortage] (in Japanese). https://www.jpeds.or.jp/modules/guidelines/index.php?content_id=145 (accessed 2026-09-18)
5. Wollenberg A, Reitamo S, Girolomoni G, et al; European Tacrolimus Ointment Study Group. Proactive treatment of atopic dermatitis in adults with 0.1% tacrolimus ointment. Allergy. 2008;63(7):742–750. PMID: 18592619.
6. Japanese Dermatological Association. Clinical Practice Guidelines for Atopic Dermatitis 2021. Japanese Dermatological Association; 2021.
7. Global Initiative for Asthma (GINA). Global Strategy for Asthma Management and Prevention 2024. GINA; 2024. https://ginasthma.org/
8. Cates CJ, Welsh EJ, Rowe BH. Holding chambers (spacers) versus nebulisers for beta-agonist treatment of acute asthma. Cochrane Database Syst Rev. 2013;(9):CD000052. PMID: 24037768.
9. Llewelyn MJ, Fitzpatrick JM, Darwin E, et al. The antibiotic course has had its day. BMJ. 2017;358:j3418. PMID: 28747365.
10. Zimmerman TJ, Kooner KS, Kandarakis AS, Ziegler LP. Improving the therapeutic index of topically applied ocular drugs. Arch Ophthalmol. 1984;102(4):551–553. PMID: 6704011.
11. Centers for Disease Control and Prevention. Healthy Habits: Antibiotic Do's and Don'ts. https://www.cdc.gov/antibiotic-use/about/index.html (last reviewed 2025-09-23; accessed 2026-09-18)