Wednesday, April 3, 2019

Counselling Points for Oral Griseofulvin


How to take ?
  • This medicine should be taken immediately after meals / (especially) with a fatty meal (peanuts or ice cream) to increase absorption, or with food or milk to avoid GI upset.
  • This medicine must be taken at regular intervals. Do not stop taking it unless instructed by the doctor.


Precautions
  • Inform your doctor if you have allergies to penicillin (risk of cross allergy - however, known penicillin-sensitive patients have been treated successfully without complications).
  • Maintain good hygiene as this is important in managing fungal infections.
  • Avoid alcohol while on this medicine; otherwise you may experience severe flushing, headache, nausea, vomiting and stomach cramps (disulfiram-like reaction).

Potential Side Effects
  • Griseofulvin may cause dizziness. If affected, do not drive, operate machinery, or take part in any activity in which you need to be alert.
  • Other side effects may include any of the following: diarrhoea, tiredness, difficulty sleeping, vomiting, nausea, stomach discomfort and headache.
  • This medicine may cause your skin to be more sensitive to sunlight. Avoid direct and prolonged exposure to the sun and other forms of ultraviolet (UV) light like tanning beds or sun lamps.
  • Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following: [watchout for TEN / SJS]
  • numbness or tingling sensation in the hands and feet
  • severe diarrhoea or diarrhoea with severe stomach cramps or bloody stools 
  • blistering of the skin, mouth, eyes and genitals 
  • fever with persistent sore throat or mouth ulcers, unusual bleeding or bruising


Pregnancy & Breastfeeding
  • Women: Do not take Griseofulvin if you are breastfeeding, pregnant or planning to have a baby soon. If you become pregnant while being treated with this medicine, alert your doctor immediately. Effective contraception required during and for at least 1 month after administration to women (important: effectiveness of oral contraceptives may be reduced, additional contraceptive precautions e.g. barrier method, required).
  • Men: Should avoid fathering a child during and for at least 6 months after administration as may damage sperm cells.


Additional comments on griseofulvin & pregnancy:

In terms of data on pregnancy category:

(1)  Some claimed Pregnancy Category X – as above.

(2)  Some claimed Pregnancy Category C – e.g.:
·         *  Briggs 10th Edi:
o   Limited human data, probably compatible. Although the animal reproductive data suggest risk, the human pregnancy experience is too limited for a complete assessment of the embryo–fetal risk. However, griseofulvin is best avoided during organogenesis because the use of an antifungal agent is seldom essential during this time.
o   A Hungarian retrospective study based on the Hungarian case–control cohort compared 38 151 normal pregnancies and 22 843 pregnancies with birth defects in relation to their exposure to griseofulvin (reported in 7 and 21 cases, respectively).63It did not appear to be associated with any birth defect or with any excess of conjoined twins.
o   Griseofulvin is classified as category C by the FDA. It is carcinogenic, embryotoxic and teratogenic in rodents. Human data are too limited to allow its use in pregnancy, especially in the first trimester.

(3)  Micromedex: Australia categorises griseofulvin as B3:
Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed.
Studies in animals have shown evidence of an increased occurrence of fetal damage, the significance of which is considered uncertain in humans.


References:
5.     BNF 76 [2018/19]
6.     Lexicomp - Griseofulvin: Drug Information
7.     Briggs 10th Edition
8.     Micromedex
[All references accessed on 3 April 2019]