Cysteamine
Cysteamine is a radiation-protective agent that oxidizes in air to form cystamine. It can be given intravenously or orally to treat radiation sickness. The bitartrate and hydrochloride salt forms are indicated for the treatment of neuropathic cystinosis in patients 6 years old and older.
Mechanism of effect
The free thiol cysteamine depletes cystinotic leukocytes and other cells of cystine, whose accumulation is considered the cause of organ damage in cystinosis. Cysteamine cleaves the disulfide bond with cystine to produce molecules that can escape the metabolic defect in cystinosis and cystinuria.
Pharmacodynamic
People born without the ability to metabolize the amino acid cystine suffer from cystinosis, a rare inherited disorder characterized by the deposition and accumulation of cystine crystals throughout the body. These crystals cause considerable damage, particularly in the kidney and eye. Kidney failure can occur by the age of 10 in untreated patients. Cysteamine prevents the accumulation of cystine crystals and is prescribed to prevent further kidney and eye damage. Cysteamine helps to convert cystine into less harmful chemical forms that can be removed from cells.
Pharmacokinetics
Onset: 1-1.8 hr
Duration: 6-12 hr
Peak plasma time: 1.4 hr
Vd: 156 L
Bioavailability: Rapidly absorbed
Protein Bound: 52% (mainly albumin)
Excretion: Small amount excreted in urine
Dialyzable: PD: yes, HD: no data
Drug indications
Cystinosis, Nephropathic
Corneal cystine crystal accumulation
Dosage
Blood disorders, hepatic impairment, seizures
Withhold if mild/moderate rash develops and restart at lower dose with subsequent titration to therapeutic dose; do not rechallenge if severe skin rash (eg, erythema multiforme bullosa, toxic epidermal necrolysis) develops
Scoliosis, osteopenia, compression fractures accompanied by leg pain and joint hyperextension may occur
Do NOT give whole capsules to <6 years due to risk of aspiration, open capsule & sprinkle on food
Temporarily suspend if serious GI or CNS symptoms
Monitor: Leukocyte cystine levels
May cause abnormal liver function tests
Drug contraindications
Hypersensitivity to cysteamine or penicillamine
Interactions
There are no known drug interactions for cysteamine
Alerts
Blood disorders, hepatic impairment, seizures
Withhold if mild/moderate rash develops and restart at lower dose with subsequent titration to therapeutic dose; do not rechallenge if severe skin rash (eg, erythema multiforme bullosa, toxic epidermal necrolysis) develops
Scoliosis, osteopenia, compression fractures accompanied by leg pain and joint hyperextension may occur
Do NOT give whole capsules to <6 years due to risk of aspiration, open capsule & sprinkle on food
Temporarily suspend if serious GI or CNS symptoms
Monitor: Leukocyte cystine levels
May cause abnormal liver function tests
Points of recommendation
Tell all of your health care providers that you take this medicine (cysteamine capsules). This includes your doctors, nurses, pharmacists, and dentists.
Avoid driving and doing other tasks or actions that call for you to be alert until you see how this medicine (cysteamine capsules) affects you.
Have blood work checked as you have been told by the doctor. Talk with the doctor.
Have your urine checked as you have been told by your doctor.
Have an eye exam as you have been told by your doctor.
Avoid drinking alcohol while taking this medicine (cysteamine capsules).
This medicine may raise the chance of ulcers or bleeding from the stomach or bowel. Talk with the doctor.
Low white blood cell counts have happened with this medicine (cysteamine capsules). This may lead to a higher chance of getting an infection. Call your doctor right away if you have signs of infection like fever, chills, or sore throat.
Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using this medicine (cysteamine capsules) while you are pregnant.
If your child's weight changes, talk with the doctor. The dose of this medicine (cysteamine capsules) may need to be changed.
Use this medicine (cysteamine capsules) as ordered by your doctor. Read all information given to you. Follow all instructions closely.
Swallow whole. Do not chew or crush.
To gain the most benefit, do not miss doses.
Keep taking this medicine (cysteamine capsules) as you have been told by your doctor or other health care provider, even if you feel well.
You may sprinkle contents of capsule on soft food or liquid. Do not chew.
Take a missed dose as soon as you think about it.
If it is less than 2 hours until your next dose, skip the missed dose and go back to your normal time.
Do not take 2 doses at the same time or extra doses.
Ask a Pharmacist