[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Anthelmintics](https://durgical.com/en/pharmacology/classes/anthelmintics/) › Diethylcarbamazine

# Diethylcarbamazine

## Anthelmintics?

Anthelmintics

Oral antifilarial that clears microfilariae and harms adult worms in lymphatic filariasis and loiasis; dangerous if onchocerciasis is present.

Updated Nov 12, 2026

Also called: DEC, diethylcarbamazine citrate

## Quick facts

**Group**
[Anthelmintics](https://durgical.com/en/pharmacology/classes/anthelmintics/)

**Target**
Filarial microfilariae and adult worms (mechanism not established)

**Used for**
Lymphatic filariasis · Loiasis

**Key effects**
Dizziness · Fever and muscle or joint pain

**Monitor**
Fever · Eye symptoms or confusion

**ATC**
P02CB02

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

Diethylcarbamazine is a piperazine derivative whose exact mechanism is unknown. Microfilariae of Wuchereria bancrofti, Brugia malayi and Loa loa vanish quickly from the blood after a dose, and the drug also damages some adult worms. Most adverse effects come from the host's inflammatory response to the dying parasites, not from the drug itself.

- Microfilariae in the blood become vulnerable (exact mechanism unknown)
- The immune system clears them quickly from the blood
- Some adult worms in lymphatics are also killed
- Dying parasites trigger the inflammatory side effects

## Indications

- Lymphatic filariasis (individual treatment, and with albendazole, or ivermectin and albendazole, in mass drug administration where onchocerciasis is absent) [Lymphatic filariasis →](https://durgical.com/en/conditions/lymphatic-filariasis/)
- Loiasis, with specialist care when the microfilarial load is high
- Tropical pulmonary eosinophilia (longer course)

## Adverse effects

### Common

- Dizziness, nausea and headache
- Fever and muscle or joint pain, more with heavy microfilarial loads
- Painful lymph nodes or lymphatic swelling as adult worms die

### Serious (rare, important)

- Severe skin and eye reactions (Mazzotti reaction) and eye damage in people with onchocerciasis
- Encephalopathy, retinal haemorrhage and kidney failure with high Loa loa loads

## Contraindications

- Onchocerciasis, or possible co-infection, because of severe skin and eye reactions
- High Loa loa microfilarial load, except under specialist care

## Key interactions

**Urine-alkalinising drugs**
Alkaline urine slows elimination and raises levels, increasing both effect and toxicity.

**Albendazole and ivermectin**
Combined in mass treatment for lymphatic filariasis where onchocerciasis and loiasis are absent.

## What is monitored

- Fever, headache and joint pain in the first days (reactions to dying parasites)
- Eye symptoms or confusion, which need urgent assessment
- Microfilarial count before and after treatment

## Administration and safety

- Oral
- Onchocerciasis is ruled out first in anyone exposed in an endemic area
- Loa loa is screened for before treatment in people from Central and West Africa

## Pregnancy and breastfeeding

Available data suggest it is safe in pregnancy; it is still given only after the infection and possible co-infections have been assessed.

## Nursing care

- Ask about travel or residence in areas with onchocerciasis or loiasis
- Warn that fever and aches in the first days usually mean worms are dying, and report eye pain or confusion
- Explain that lymphoedema and hydrocele do not improve with DEC and need limb care or surgery
- Teach mosquito-bite prevention

## Pharmacokinetics

**Absorption**
Rapidly absorbed by mouth.

**Elimination**
Mainly by the kidneys; alkaline urine slows elimination and raises levels, so kidney function and urine pH matter.

## Memory aid

«DEC: Don't Even Consider it in Onchocerciasis»: DEC clears filariae from the blood, but in river blindness it inflames the eyes and skin.

## Test yourself

Think of the answer, then tap the question to see it.

## Why must onchocerciasis be ruled out before giving diethylcarbamazine?

Killing Onchocerca microfilariae in skin and eyes causes a severe reaction (Mazzotti) and can damage the eyes.

## What causes most of DEC's adverse effects?

The host's inflammatory response to dying microfilariae and adult worms, more intense with heavy infection.

## Which complication is feared when DEC is given to someone with a high Loa loa load?

Encephalopathy, which can be fatal, along with retinal haemorrhage and kidney failure.

## Does DEC reverse established lymphoedema or hydrocele?

No. Most affected people no longer have active infection; limb care helps lymphoedema and hydrocele needs surgery.

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[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 3

- [Ivermectin](https://durgical.com/en/pharmacology/ivermectin/)
- [Albendazole](https://durgical.com/en/pharmacology/albendazole/)
- [Moxidectin](https://durgical.com/en/pharmacology/moxidectin/)

## Related conditions 1

- [Lymphatic filariasis](https://durgical.com/en/conditions/lymphatic-filariasis/)

[← Back to the class: Anthelmintics](https://durgical.com/en/pharmacology/classes/anthelmintics/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Clinical Treatment of Lymphatic Filariasis](https://www.cdc.gov/filarial-worms/hcp/clinical-care/index.html) (Centers for Disease Control and Prevention (CDC), 2026); [Lymphatic filariasis](https://www.who.int/news-room/fact-sheets/detail/lymphatic-filariasis) (World Health Organization (WHO), 2026); [eEML - Electronic Essential Medicines List](https://list.essentialmeds.org/?query=diethylcarbamazine) (World Health Organization (WHO), 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/diethylcarbamazine/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/diethylcarbamazine/