Full blood and platelet counts should be performed and renal function should be assessed prior to treatment with penicillamine.
Monitoring of blood and platelet counts should be carried out at appropriate intervals, together with urinalysis for detection of haematuria and proteinuria (see section 4.8). Urinalysis should be carried out weekly at first, and following each increase in dose, then monthly, although longer intervals may be adequate for cystinuria and Wilson's disease. Increasing or persistent proteinuria may necessitate withdrawal of therapy.
During the first eight weeks of therapy full blood counts should be carried out weekly or fortnightly and also in the week after any increase in dose, otherwise monthly thereafter. In cystinuria or Wilson's disease, longer intervals may be adequate.
If platelets fall below 120,000 per mm3 or white blood cells below 2,500 per mm3, or if three consecutive falls are noted within the normal range, withdrawal of treatment should be considered. When counts return to normal, treatment may be restarted at a reduced dosage, but should be permanently withdrawn on recurrence of leucopenia or thrombocytopenia. Penicillamine may potentiate the bone marrow suppression caused by clozapine.
Care should be taken and dosage modified, if needed, in patients with renal impairment (see section 4.2).
Especially careful monitoring is necessary in older people since increased toxicity has been observed in this patient population regardless of renal function.
Concomitant use of NSAIDs and other nephrotoxic drugs may increase the risk of renal damage (see section 4.5).
Penicillamine should be used with caution in patients who have had adverse reactions to gold.
Concomitant or previous treatment with gold may increase the risk of side effects with penicillamine treatment. Therefore penicillamine should be used with caution in patients who have previously had adverse reactions to gold and concomitant treatment with gold should be avoided (see section 4.5).
Penicillamine should not be used in patients who are receiving concurrently antimalarial drugs such as hydroxychloroquine phosphate, chloroquine. These drugs having similar hematologic and renal adverse reactions, could act synergistically when used together with penicillamine (See section 4.5).
If concomitant oral iron, digoxin or antacid therapy is indicated, this should not be given within two hours of taking penicillamine (see section 4.5).
Antihistamines, steroid cover, or temporary reduction of dose will control urticarial reactions (see section 4.8).
Reversible loss of taste may occur. Mineral supplements to overcome this are not recommended (see section 4.8).
Haematuria is rare, but if it occurs in the absence of renal stones or other known causes, treatment should be stopped immediately (see section 4.8).
A late rash, described as acquired epidermolysis bullosa and penicillamine dermopathy, may occur after several months or years of therapy. This may necessitate a reduction in dosage (see section 4.8).
Breast enlargement has been reported as a rare complication of penicillamine therapy in both women and men (see section 4.8). Danazol has been used successfully to treat breast enlargement which does not regress on drug discontinuation.
The use of DMARDs, including penicillamine, has been linked to the development of septic arthritis in patients with rheumatoid arthritis, although rheumatoid arthritis is a stronger predictor for the development of septic arthritis than the use of a DMARD (see section 4.8).
Deterioration of the neurological symptoms of Wilson's disease (dystonia, rigidity, tremor, dysarthria) have been reported following introduction of penicillamine in patients treated for this condition. This may be a consequence of mobilisation and redistribution of copper from the liver to the brain (see section 4.8).
Pyridoxine daily may be given to patients on long term therapy, especially if they are on a restricted diet, since penicillamine increases the requirement of this vitamin (see section 4.5).
These tablets contain lactose. Patients with rare hereditary problems of galactose intolerance, total lactase deficiency or glucose-galactose malabsorption should not take this medicine.
This medicine contains less than 1 mmol sodium (23 mg) per tablet, that is to say essentially 'sodium-free'.