Topical psoriasis/seborrhoea preparation Pregnancy: SPC §4.6 states only: 'No known side effects.'

Coal tar with salicylic acid

Brand names: Coco-Scalp

A topical preparation combining coal tar with salicylic acid, used for chronic scaling skin and scalp conditions, particularly plaque psoriasis and seborrhoeic dermatitis, where thick adherent scale is a feature.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Wet the hair thoroughly, then massage a small amount of the shampoo into the scalp (approximately a quantity the size of a fifty pence piece for short hair, adjusting up depending on length/thickness of hair), leaving on for a few minutes before washing out; if necessary, repeat, producing a rich lather; rinse hair well and dry

Route: Topical - use as a shampoo on the scalp; for external use only, keep away from the eyes

Frequency: Daily if necessary, reducing the frequency of use to once or twice a week as the condition improves; thereafter, occasional use may be necessary

SOURCE: UK SPC (eMC) for Capasal Therapeutic Shampoo, §4.2 (https://www.medicines.org.uk/emc/product/3751/smpc). The SPC gives a single regimen 'For adults, children and the elderly' - no separate paediatric or elderly instruction, no weight-based dose and no numeric maximum quantity. §4.4: for external use only; keep away from the eyes; keep out of the sight and reach of children. Contains 0.15 mg sodium benzoate (E 211) per gram of shampoo, which may cause local irritation and may increase jaundice in newborn babies (up to 4 weeks old). In case of irritation, or if there is no improvement after 4 weeks, or the scalp condition seems to look or feel worse, discontinue treatment and tell your doctor, pharmacist or nurse. The US openFDA record in the bundle is a different product (an OTC therapeutic tar gel/shampoo) and its directions ('use at least twice a week or as directed by a doctor') were not used for this draft.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substances or to any of the excipients

Side effects

None known (SPC §4.8)

Interactions

None known (SPC §4.5)

Clinical monograph

How it works

Coal tar provides anti-inflammatory, antiscaling and antipruritic effects while salicylic acid acts as a keratolytic, softening and removing scale and improving penetration of the coal tar.

Prescribing in practice

Coal tar increases sensitivity to ultraviolet light, so treated areas should be protected from strong sunlight and care taken if phototherapy is also used.
Avoid application to broken, infected or acutely inflamed skin, and keep away from the eyes, as both components can irritate.
Salicylic acid is absorbed through the skin, so avoid extensive or prolonged use, particularly in children, to reduce the risk of salicylate toxicity.

Monitoring

No routine laboratory monitoring is required; review the treated area for irritation and clinical response.

Counselling the patient

Apply as directed, avoid the eyes and surrounding healthy skin, and wash your hands afterwards.
Expect a tar odour and possible staining of fabrics and light hair.
Protect treated skin from strong sunlight and stop if irritation develops.

Evidence & guidelines

Coal tar with salicylic acid is an established keratolytic-antiscaling option for scaling psoriasis and is used within NICE-supported stepped topical therapy.

Reference: Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways